Merge branch 'master' of github.com:MongoEngine/mongoengine into add_validation_to_doc

.gitignore

@@ -1,8 +1,15 @@
-.*
 !.gitignore
 *~
 *.py[co]
 .*.sw[po]
+.cache/
+.coverage
+.coveragerc
+.env
+.idea/
+.pytest_cache/
+.tox/
+.eggs/
 *.egg
 docs/.build
 docs/_build
@@ -13,8 +20,6 @@ env/
 .settings
 .project
 .pydevproject
-tests/test_bugfix.py
 htmlcov/
 venv
 venv3
-scratchpad

.landscape.yml

@@ -5,17 +5,12 @@ pylint:
 
     options:
         additional-builtins:
-            # add xrange and long as valid built-ins. In Python 3, xrange is
+            # add long as valid built-ins.
-            # translated into range and long is translated into int via 2to3 (see
-            # "use_2to3" in setup.py). This should be removed when we drop Python
-            # 2 support (which probably won't happen any time soon).
-            - xrange
             - long
 
 pyflakes:
     disable:
-        # undefined variables are already covered by pylint (and exclude
+        # undefined variables are already covered by pylint (and exclude long)
-        # xrange & long)
         - F821
 
 ignore-paths:

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+fail_fast: false
+repos:
+    - repo: https://github.com/ambv/black
+      rev: 19.10b0
+      hooks:
+        - id: black
+    - repo: https://gitlab.com/pycqa/flake8
+      rev: 3.8.0a2
+      hooks:
+        - id: flake8
+          additional_dependencies:
+            - flake8-import-order

.travis.yml

@@ -1,13 +1,10 @@
 # For full coverage, we'd have to test all supported Python, MongoDB, and
 # PyMongo combinations. However, that would result in an overly long build
 # with a very large number of jobs, hence we only test a subset of all the
-# combinations:
+# combinations.
-# * MongoDB v3.4 & the latest PyMongo v3.x is currently the "main" setup,
+# * Python3.7, MongoDB v3.4 & the latest PyMongo v3.x is currently the "main" setup,
-#   tested against Python v2.7, v3.5, v3.6, and PyPy.
+# Other combinations are tested. See below for the details or check the travis jobs
-# * Besides that, we test the lowest actively supported Python/MongoDB/PyMongo
+
-#   combination: MongoDB v3.4, PyMongo v3.4, Python v2.7.
-# * MongoDB v3.6 is tested against Python v3.6, and PyMongo v3.6, v3.7, v3.8.
-#
 # We should periodically check MongoDB Server versions supported by MongoDB
 # Inc., add newly released versions to the test matrix, and remove versions
 # which have reached their End of Life. See:
@@ -16,65 +13,69 @@
 #
 # Reminder: Update README.rst if you change MongoDB versions we test.
 
-
 language: python
+dist: xenial
 python:
-- 2.7
 - 3.5
 - 3.6
-- pypy
+- 3.7
-
+- 3.8
-dist: xenial
+- pypy3
 
 env:
   global:
-    - MONGODB_3_4=3.4.17
+    - MONGODB_3_4=3.4.19
-    - MONGODB_3_6=3.6.12
+    - MONGODB_3_6=3.6.13
+    - MONGODB_4_0=4.0.13
+
+    - PYMONGO_3_4=3.4
+    - PYMONGO_3_6=3.6
+    - PYMONGO_3_9=3.9
+    - PYMONGO_3_11=3.11
+
+    - MAIN_PYTHON_VERSION=3.7
   matrix:
-    - MONGODB=${MONGODB_3_4} PYMONGO=3.x
+    - MONGODB=${MONGODB_3_4} PYMONGO=${PYMONGO_3_11}
 
 matrix:
-
   # Finish the build as soon as one job fails
   fast_finish: true
 
   include:
-  - python: 2.7
-    env: MONGODB=${MONGODB_3_4} PYMONGO=3.4.x
-  - python: 3.6
-    env: MONGODB=${MONGODB_3_6} PYMONGO=3.x
   - python: 3.7
-    env: MONGODB=${MONGODB_3_6} PYMONGO=3.x
+    env: MONGODB=${MONGODB_3_6} PYMONGO=${PYMONGO_3_6}
-
+  - python: 3.7
+    env: MONGODB=${MONGODB_3_6} PYMONGO=${PYMONGO_3_9}
+  - python: 3.7
+    env: MONGODB=${MONGODB_3_6} PYMONGO=${PYMONGO_3_11}
+  - python: 3.8
+    env: MONGODB=${MONGODB_4_0} PYMONGO=${PYMONGO_3_11}
 
 install:
   # Install Mongo
   - wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-${MONGODB}.tgz
   - tar xzf mongodb-linux-x86_64-${MONGODB}.tgz
   - ${PWD}/mongodb-linux-x86_64-${MONGODB}/bin/mongod --version
-  # Install python dependencies
+  # Install Python dependencies.
   - pip install --upgrade pip
   - pip install coveralls
-  - pip install flake8 flake8-import-order
+  - pip install pre-commit
-  - pip install tox         # tox 3.11.0 has requirement virtualenv>=14.0.0
+  - pip install tox
-  - pip install virtualenv  # virtualenv>=14.0.0 has dropped Python 3.2 support (and pypy3 is based on py32)
+  # tox dryrun to setup the tox venv (we run a mock test).
-  # Install the tox venv
+  - tox -e $(echo py$TRAVIS_PYTHON_VERSION-mg$PYMONGO | tr -d . | sed -e 's/pypypy/pypy/') -- -a "-k=test_ci_placeholder"
-  - tox -e $(echo py$TRAVIS_PYTHON_VERSION-mg$PYMONGO | tr -d . | sed -e 's/pypypy/pypy/') -- -e test
 
 before_script:
   - mkdir ${PWD}/mongodb-linux-x86_64-${MONGODB}/data
   - ${PWD}/mongodb-linux-x86_64-${MONGODB}/bin/mongod --dbpath ${PWD}/mongodb-linux-x86_64-${MONGODB}/data --logpath ${PWD}/mongodb-linux-x86_64-${MONGODB}/mongodb.log --fork
-  - if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then flake8 .; else echo "flake8 only runs on py27"; fi   # Run flake8 for py27
+  # Run pre-commit hooks (black, flake8, etc) on entire codebase
+  - if [[ $TRAVIS_PYTHON_VERSION == $MAIN_PYTHON_VERSION ]]; then pre-commit run -a; else echo "pre-commit checks only runs on py37"; fi
   - mongo --eval 'db.version();'    # Make sure mongo is awake
 
 script:
-  - tox -e $(echo py$TRAVIS_PYTHON_VERSION-mg$PYMONGO | tr -d . | sed -e 's/pypypy/pypy/') -- --with-coverage
+  - tox -e $(echo py$TRAVIS_PYTHON_VERSION-mg$PYMONGO | tr -d . | sed -e 's/pypypy/pypy/') -- -a "--cov=mongoengine"
 
-# For now only submit coveralls for Python v2.7. Python v3.x currently shows
-# 0% coverage. That's caused by 'use_2to3', which builds the py3-compatible
-# code in a separate dir and runs tests on that.
 after_success:
-- if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then coveralls --verbose; fi
+  - if [[ $TRAVIS_PYTHON_VERSION == $MAIN_PYTHON_VERSION ]]; then coveralls --verbose; else echo "coveralls only sent for py37"; fi
 
 notifications:
   irc: irc.freenode.org#mongoengine
@@ -96,11 +97,11 @@ deploy:
   distributions: "sdist bdist_wheel"
 
   # Only deploy on tagged commits (aka GitHub releases) and only for the parent
-  # repo's builds running Python v2.7 along with PyMongo v3.x and MongoDB v3.4.
+  # repo's builds running Python v3.7 along with PyMongo v3.x and MongoDB v3.4.
   # We run Travis against many different Python, PyMongo, and MongoDB versions
   # and we don't want the deploy to occur multiple times).
   on:
     tags: true
     repo: MongoEngine/mongoengine
-    condition: ($PYMONGO = 3.x) && ($MONGODB = 3.4)
+    condition: ($PYMONGO = ${PYMONGO_3_11}) && ($MONGODB = ${MONGODB_3_4})
-    python: 2.7
+    python: 3.7

AUTHORS

@@ -252,3 +252,8 @@ that much better:
  * Paulo Amaral (https://github.com/pauloAmaral)
  * Gaurav Dadhania (https://github.com/GVRV)
  * Yurii Andrieiev (https://github.com/yandrieiev)
+ * Filip Kucharczyk (https://github.com/Pacu2)
+ * Eric Timmons (https://github.com/daewok)
+ * Matthew Simpson (https://github.com/mcsimps2)
+ * Leonardo Domingues (https://github.com/leodmgs)
+ * Agustin Barto (https://github.com/abarto)

CONTRIBUTING.rst

@@ -20,23 +20,43 @@ post to the `user group <http://groups.google.com/group/mongoengine-users>`
 Supported Interpreters
 ----------------------
 
-MongoEngine supports CPython 2.7 and newer. Language
+MongoEngine supports CPython 3.5 and newer as well as Pypy3.
-features not supported by all interpreters can not be used.
+Language features not supported by all interpreters can not be used.
-The codebase is written in python 2 so you must be using python 2
+
-when developing new features. Compatibility of the library with Python 3
+Python3 codebase
-relies on the 2to3 package that gets executed as part of the installation
+----------------------
-build. You should ensure that your code is properly converted by
+
-`2to3 <http://docs.python.org/library/2to3.html>`_.
+Since 0.20, the codebase is exclusively Python 3.
+
+Earlier versions were exclusively Python2, and were relying on 2to3 to support Python3 installs.
+Travis runs the tests against the main Python 3.x versions.
+
 
 Style Guide
 -----------
 
-MongoEngine aims to follow `PEP8 <http://www.python.org/dev/peps/pep-0008/>`_
+MongoEngine's codebase is formatted with `black <https://github.com/python/black>`_, other tools like
-including 4 space indents. When possible we try to stick to 79 character line
+flake8 are also used. Those tools will run as part of the CI and will fail in case the code is not formatted properly.
-limits. However, screens got bigger and an ORM has a strong focus on
+
-readability and if it can help, we accept 119 as maximum line length, in a
+To install all development tools, simply run the following commands:
-similar way as `django does
+
-<https://docs.djangoproject.com/en/dev/internals/contributing/writing-code/coding-style/#python-style>`_
+.. code-block:: console
+
+    $ python -m pip install -r requirements-dev.txt
+
+
+You can install `pre-commit <https://pre-commit.com/>`_ into your git hooks,
+to automatically check and fix any formatting issue before creating a
+git commit.
+
+To enable ``pre-commit`` simply run:
+
+.. code-block:: console
+
+    $ pre-commit install
+
+See the ``.pre-commit-config.yaml`` configuration file for more information
+on how it works.
 
 Testing
 -------
@@ -58,7 +78,7 @@ General Guidelines
   should adapt to the breaking change in docs/upgrade.rst.
 - Write inline documentation for new classes and methods.
 - Write tests and make sure they pass (make sure you have a mongod
-  running on the default port, then execute ``python setup.py nosetests``
+  running on the default port, then execute ``python setup.py test``
   from the cmd line to run the test suite).
 - Ensure tests pass on all supported Python, PyMongo, and MongoDB versions.
   You can test various Python and PyMongo versions locally by executing

README.rst

@@ -26,15 +26,15 @@ an `API reference <https://mongoengine-odm.readthedocs.io/apireference.html>`_.
 
 Supported MongoDB Versions
 ==========================
-MongoEngine is currently tested against MongoDB v3.4 and v3.6. Future versions
+MongoEngine is currently tested against MongoDB v3.4, v3.6 and v4.0. Future versions
 should be supported as well, but aren't actively tested at the moment. Make
 sure to open an issue or submit a pull request if you experience any problems
-with MongoDB version > 3.6.
+with MongoDB version > 4.0.
 
 Installation
 ============
 We recommend the use of `virtualenv <https://virtualenv.pypa.io/>`_ and of
-`pip <https://pip.pypa.io/>`_. You can then use ``pip install -U mongoengine``.
+`pip <https://pip.pypa.io/>`_. You can then use ``python -m pip install -U mongoengine``.
 You may also have `setuptools <http://peak.telecommunity.com/DevCenter/setuptools>`_
 and thus you can use ``easy_install -U mongoengine``. Another option is
 `pipenv <https://docs.pipenv.org/>`_. You can then use ``pipenv install mongoengine``
@@ -42,13 +42,14 @@ to both create the virtual environment and install the package. Otherwise, you c
 download the source from `GitHub <http://github.com/MongoEngine/mongoengine>`_ and
 run ``python setup.py install``.
 
+The support for Python2 was dropped with MongoEngine 0.20.0
+
 Dependencies
 ============
-All of the dependencies can easily be installed via `pip <https://pip.pypa.io/>`_.
+All of the dependencies can easily be installed via `python -m pip <https://pip.pypa.io/>`_.
 At the very least, you'll need these two packages to use MongoEngine:
 
 - pymongo>=3.4
-- six>=1.10.0
 
 If you utilize a ``DateTimeField``, you might also use a more flexible date parser:
 
@@ -58,6 +59,10 @@ If you need to use an ``ImageField`` or ``ImageGridFsProxy``:
 
 - Pillow>=2.0.0
 
+If you need to use signals:
+
+- blinker>=1.3
+
 Examples
 ========
 Some simple examples of what MongoEngine code looks like:
@@ -91,12 +96,11 @@ Some simple examples of what MongoEngine code looks like:
 
     # Iterate over all posts using the BlogPost superclass
     >>> for post in BlogPost.objects:
-    ...     print '===', post.title, '==='
+    ...     print('===', post.title, '===')
     ...     if isinstance(post, TextPost):
-    ...         print post.content
+    ...         print(post.content)
     ...     elif isinstance(post, LinkPost):
-    ...         print 'Link:', post.url
+    ...         print('Link:', post.url)
-    ...     print
     ...
 
     # Count all blog posts and its subtypes
@@ -116,7 +120,8 @@ Some simple examples of what MongoEngine code looks like:
 Tests
 =====
 To run the test suite, ensure you are running a local instance of MongoDB on
-the standard port and have ``nose`` installed. Then, run ``python setup.py nosetests``.
+the standard port and have ``pytest`` installed. Then, run ``python setup.py test``
+or simply ``pytest``.
 
 To run the test suite on every supported Python and PyMongo version, you can
 use ``tox``. You'll need to make sure you have each supported Python version
@@ -125,20 +130,18 @@ installed in your environment and then:
 .. code-block:: shell
 
     # Install tox
-    $ pip install tox
+    $ python -m pip install tox
     # Run the test suites
     $ tox
 
-If you wish to run a subset of tests, use the nosetests convention:
+If you wish to run a subset of tests, use the pytest convention:
 
 .. code-block:: shell
 
     # Run all the tests in a particular test file
-    $ python setup.py nosetests --tests tests/fields/fields.py
+    $ pytest tests/fields/test_fields.py
     # Run only particular test class in that file
-    $ python setup.py nosetests --tests tests/fields/fields.py:FieldTest
+    $ pytest tests/fields/test_fields.py::TestField
-    # Use the -s option if you want to print some debug statements or use pdb
-    $ python setup.py nosetests --tests tests/fields/fields.py:FieldTest -s
 
 Community
 =========

benchmarks/test_basic_doc_ops.py

@@ -1,11 +1,18 @@
 from timeit import repeat
 
 import mongoengine
-from mongoengine import (BooleanField, Document, EmailField, EmbeddedDocument,
+from mongoengine import (
-                         EmbeddedDocumentField, IntField, ListField,
+    BooleanField,
-                         StringField)
+    Document,
+    EmailField,
+    EmbeddedDocument,
+    EmbeddedDocumentField,
+    IntField,
+    ListField,
+    StringField,
+)
 
-mongoengine.connect(db='mongoengine_benchmark_test')
+mongoengine.connect(db="mongoengine_benchmark_test")
 
 
 def timeit(f, n=10000):
@@ -24,46 +31,41 @@ def test_basic():
 
     def init_book():
         return Book(
-            name='Always be closing',
+            name="Always be closing",
             pages=100,
-            tags=['self-help', 'sales'],
+            tags=["self-help", "sales"],
             is_published=True,
-            author_email='alec@example.com',
+            author_email="alec@example.com",
         )
 
-    print('Doc initialization: %.3fus' % (timeit(init_book, 1000) * 10**6))
+    print("Doc initialization: %.3fus" % (timeit(init_book, 1000) * 10 ** 6))
 
     b = init_book()
-    print('Doc getattr: %.3fus' % (timeit(lambda: b.name, 10000) * 10**6))
+    print("Doc getattr: %.3fus" % (timeit(lambda: b.name, 10000) * 10 ** 6))
 
     print(
-        'Doc setattr: %.3fus' % (
+        "Doc setattr: %.3fus"
-            timeit(lambda: setattr(b, 'name', 'New name'), 10000) * 10**6
+        % (timeit(lambda: setattr(b, "name", "New name"), 10000) * 10 ** 6)
-        )
     )
 
-    print('Doc to mongo: %.3fus' % (timeit(b.to_mongo, 1000) * 10**6))
+    print("Doc to mongo: %.3fus" % (timeit(b.to_mongo, 1000) * 10 ** 6))
 
-    print('Doc validation: %.3fus' % (timeit(b.validate, 1000) * 10**6))
+    print("Doc validation: %.3fus" % (timeit(b.validate, 1000) * 10 ** 6))
 
     def save_book():
-        b._mark_as_changed('name')
+        b._mark_as_changed("name")
-        b._mark_as_changed('tags')
+        b._mark_as_changed("tags")
         b.save()
 
-    print('Save to database: %.3fus' % (timeit(save_book, 100) * 10**6))
+    print("Save to database: %.3fus" % (timeit(save_book, 100) * 10 ** 6))
 
     son = b.to_mongo()
     print(
-        'Load from SON: %.3fus' % (
+        "Load from SON: %.3fus" % (timeit(lambda: Book._from_son(son), 1000) * 10 ** 6)
-            timeit(lambda: Book._from_son(son), 1000) * 10**6
-        )
     )
 
     print(
-        'Load from database: %.3fus' % (
+        "Load from database: %.3fus" % (timeit(lambda: Book.objects[0], 100) * 10 ** 6)
-            timeit(lambda: Book.objects[0], 100) * 10**6
-        )
     )
 
     def create_and_delete_book():
@@ -72,9 +74,8 @@ def test_basic():
         b.delete()
 
     print(
-        'Init + save to database + delete: %.3fms' % (
+        "Init + save to database + delete: %.3fms"
-            timeit(create_and_delete_book, 10) * 10**3
+        % (timeit(create_and_delete_book, 10) * 10 ** 3)
-        )
     )
 
 
@@ -92,42 +93,36 @@ def test_big_doc():
 
     def init_company():
         return Company(
-            name='MongoDB, Inc.',
+            name="MongoDB, Inc.",
             contacts=[
-                Contact(
+                Contact(name="Contact %d" % x, title="CEO", address="Address %d" % x)
-                    name='Contact %d' % x,
-                    title='CEO',
-                    address='Address %d' % x,
-                )
                 for x in range(1000)
-            ]
+            ],
         )
 
     company = init_company()
-    print('Big doc to mongo: %.3fms' % (timeit(company.to_mongo, 100) * 10**3))
+    print("Big doc to mongo: %.3fms" % (timeit(company.to_mongo, 100) * 10 ** 3))
 
-    print('Big doc validation: %.3fms' % (timeit(company.validate, 1000) * 10**3))
+    print("Big doc validation: %.3fms" % (timeit(company.validate, 1000) * 10 ** 3))
 
     company.save()
 
     def save_company():
-        company._mark_as_changed('name')
+        company._mark_as_changed("name")
-        company._mark_as_changed('contacts')
+        company._mark_as_changed("contacts")
         company.save()
 
-    print('Save to database: %.3fms' % (timeit(save_company, 100) * 10**3))
+    print("Save to database: %.3fms" % (timeit(save_company, 100) * 10 ** 3))
 
     son = company.to_mongo()
     print(
-        'Load from SON: %.3fms' % (
+        "Load from SON: %.3fms"
-            timeit(lambda: Company._from_son(son), 100) * 10**3
+        % (timeit(lambda: Company._from_son(son), 100) * 10 ** 3)
-        )
     )
 
     print(
-        'Load from database: %.3fms' % (
+        "Load from database: %.3fms"
-            timeit(lambda: Company.objects[0], 100) * 10**3
+        % (timeit(lambda: Company.objects[0], 100) * 10 ** 3)
-        )
     )
 
     def create_and_delete_company():
@@ -136,13 +131,12 @@ def test_big_doc():
         c.delete()
 
     print(
-        'Init + save to database + delete: %.3fms' % (
+        "Init + save to database + delete: %.3fms"
-            timeit(create_and_delete_company, 10) * 10**3
+        % (timeit(create_and_delete_company, 10) * 10 ** 3)
-        )
     )
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     test_basic()
-    print('-' * 100)
+    print("-" * 100)
     test_big_doc()

benchmarks/test_inserts.py

@@ -4,12 +4,14 @@ import timeit
 def main():
     setup = """
 from pymongo import MongoClient
+
 connection = MongoClient()
 connection.drop_database('mongoengine_benchmark_test')
 """
 
     stmt = """
 from pymongo import MongoClient
+
 connection = MongoClient()
 
 db = connection.mongoengine_benchmark_test
@@ -26,10 +28,10 @@ myNoddys = noddy.find()
 [n for n in myNoddys]  # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
-    print('PyMongo: Creating 10000 dictionaries.')
+    print("PyMongo: Creating 10000 dictionaries.")
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
     stmt = """
 from pymongo import MongoClient, WriteConcern
@@ -49,13 +51,14 @@ myNoddys = noddy.find()
 [n for n in myNoddys]  # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
     print('PyMongo: Creating 10000 dictionaries (write_concern={"w": 0}).')
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
     setup = """
 from pymongo import MongoClient
+
 connection = MongoClient()
 connection.drop_database('mongoengine_benchmark_test')
 connection.close()
@@ -78,10 +81,10 @@ myNoddys = Noddy.objects()
 [n for n in myNoddys]  # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
-    print('MongoEngine: Creating 10000 dictionaries.')
+    print("MongoEngine: Creating 10000 dictionaries.")
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
     stmt = """
 for i in range(10000):
@@ -96,10 +99,10 @@ myNoddys = Noddy.objects()
 [n for n in myNoddys]  # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
-    print('MongoEngine: Creating 10000 dictionaries (using a single field assignment).')
+    print("MongoEngine: Creating 10000 dictionaries (using a single field assignment).")
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
     stmt = """
 for i in range(10000):
@@ -112,10 +115,10 @@ myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
     print('MongoEngine: Creating 10000 dictionaries (write_concern={"w": 0}).')
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
     stmt = """
 for i in range(10000):
@@ -128,10 +131,12 @@ myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
-    print('MongoEngine: Creating 10000 dictionaries (write_concern={"w": 0}, validate=False).')
+    print(
+        'MongoEngine: Creating 10000 dictionaries (write_concern={"w": 0}, validate=False).'
+    )
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
     stmt = """
 for i in range(10000):
@@ -144,10 +149,12 @@ myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
 
-    print('-' * 100)
+    print("-" * 100)
-    print('MongoEngine: Creating 10000 dictionaries (force_insert=True, write_concern={"w": 0}, validate=False).')
+    print(
+        'MongoEngine: Creating 10000 dictionaries (force_insert=True, write_concern={"w": 0}, validate=False).'
+    )
     t = timeit.Timer(stmt=stmt, setup=setup)
-    print('{}s'.format(t.timeit(1)))
+    print("{}s".format(t.timeit(1)))
 
 
 if __name__ == "__main__":

docs/changelog.rst

@@ -6,208 +6,264 @@ Changelog
 Development
 ===========
 - (Fill this out as you fix issues and develop your features).
+- When using pymongo >= 3.7, make use of Collection.count_documents instead of Collection.count
+    and Cursor.count that got deprecated in pymongo >= 3.7.
+    This should have a negative impact on performance of count see Issue #2219
+- Fix a bug that made the queryset drop the read_preference after clone().
+- Fix the behavior of Doc.objects.limit(0) which should return all documents (similar to mongodb) #2311
+- Bug fix in ListField when updating the first item, it was saving the whole list, instead of
+    just replacing the first item (as it's usually done) #2392
+
+Changes in 0.20.0
+=================
+- ATTENTION: Drop support for Python2
+- Add Mongo 4.0 to Travis
+- Fix error when setting a string as a ComplexDateTimeField #2253
+- Bump development Status classifier to Production/Stable #2232
+- Improve Queryset.get to avoid confusing MultipleObjectsReturned message in case multiple match are found #630
+- Fixed a bug causing inaccurate query results, while combining ``__raw__`` and regular filters for the same field #2264
+- Add support for the `elemMatch` projection operator in .fields() (e.g BlogPost.objects.fields(elemMatch__comments="test")) #2267
+- DictField validate failed without default connection (bug introduced in 0.19.0) #2239
+- Remove methods that were deprecated years ago:
+    - name parameter in Field constructor e.g `StringField(name="...")`, was replaced by db_field
+    - Queryset.slave_okay() was deprecated since pymongo3
+    - dropDups was dropped with MongoDB3
+    - ``Queryset._ensure_indexes`` and ``Queryset.ensure_indexes``, the right method to use is ``Document.ensure_indexes``
+- Added pre-commit for development/CI #2212
+- Renamed requirements-lint.txt to requirements-dev.txt #2212
+- Support for setting ReadConcern #2255
+
+Changes in 0.19.1
+=================
+- Tests require Pillow < 7.0.0 as it dropped Python2 support
+- DEPRECATION: The interface of ``QuerySet.aggregate`` method was changed, it no longer takes an unpacked list of
+    pipeline steps (*pipeline) but simply takes the pipeline list just like ``pymongo.Collection.aggregate`` does. #2079
+
+Changes in 0.19.0
+=================
+- BREAKING CHANGE: ``class_check`` and ``read_preference`` keyword arguments are no longer available when filtering a ``QuerySet``. #2112
+    - Instead of ``Doc.objects(foo=bar, read_preference=...)`` use ``Doc.objects(foo=bar).read_preference(...)``.
+    - Instead of ``Doc.objects(foo=bar, class_check=False)`` use ``Doc.objects(foo=bar).clear_cls_query(...)``.
+    - This change also renames the private ``QuerySet._initial_query`` attribute to ``_cls_query``.
+- BREAKING CHANGE: Removed the deprecated ``format`` param from ``QuerySet.explain``. #2113
+- BREAKING CHANGE: Renamed ``MongoEngineConnectionError`` to ``ConnectionFailure``. #2111
+    - If you catch/use ``MongoEngineConnectionError`` in your code, you'll have to rename it.
+- BREAKING CHANGE: Positional arguments when instantiating a document are no longer supported. #2103
+    - From now on keyword arguments (e.g. ``Doc(field_name=value)``) are required.
+- BREAKING CHANGE: A ``LazyReferenceField`` is now stored in the ``_data`` field of its parent as a ``DBRef``, ``Document``, or ``EmbeddedDocument`` (``ObjectId`` is no longer allowed). #2182
+- DEPRECATION: ``Q.empty`` & ``QNode.empty`` are marked as deprecated and will be removed in a next version of MongoEngine. #2210
+    - Added ability to check if Q or QNode are empty by parsing them to bool.
+    - Instead of ``Q(name="John").empty`` use ``not Q(name="John")``.
+- Fix updating/modifying/deleting/reloading a document that's sharded by a field with ``db_field`` specified. #2125
+- Only set no_cursor_timeout when requested (fixes an incompatibility with MongoDB 4.2) #2148
+- ``ListField`` now accepts an optional ``max_length`` parameter. #2110
+- Improve error message related to InvalidDocumentError #2180
+- Added BulkWriteError to replace NotUniqueError which was misleading in bulk write insert #2152
+- Added ability to compare Q and Q operations #2204
+- Added ability to use a db alias on query_counter #2194
+- Added ability to specify collations for querysets with ``Doc.objects.collation`` #2024
+- Fix updates of a list field by negative index #2094
+- Switch from nosetest to pytest as test runner #2114
+- The codebase is now formatted using ``black``. #2109
+- Documentation improvements:
+    - Documented how `pymongo.monitoring` can be used to log all queries issued by MongoEngine to the driver.
+
+Changes in 0.18.2
+=================
+- Replace deprecated PyMongo v2.x methods with their v3.x equivalents in the ``SequenceField``. #2097
+- Various code clarity and documentation improvements.
 
 Changes in 0.18.1
 =================
-- Fix a bug introduced in 0.18.0 which was causing `.save()` to update all the fields
+- Fix a bug introduced in 0.18.0 which was causing ``Document.save`` to update all the fields instead of updating only the modified fields. This bug only occurred when using a custom PK. #2082
-    instead of updating only the modified fields. This bug only occurs when using custom pk #2082
+- Add Python 3.7 to Travis CI. #2058
-- Add Python 3.7 in travis #2058
 
 Changes in 0.18.0
 =================
 - Drop support for EOL'd MongoDB v2.6, v3.0, and v3.2.
-- MongoEngine now requires PyMongo >= v3.4. Travis CI now tests against MongoDB v3.4 – v3.6 and PyMongo v3.4 – v3.6 (#2017 #2066).
+- MongoEngine now requires PyMongo >= v3.4. Travis CI now tests against MongoDB v3.4 – v3.6 and PyMongo v3.4 – v3.6. #2017 #2066
-- Improve performance by avoiding a call to `to_mongo` in `Document.save()` #2049
+- Improve performance by avoiding a call to ``to_mongo`` in ``Document.save``. #2049
 - Connection/disconnection improvements:
-    - Expose `mongoengine.connection.disconnect` and `mongoengine.connection.disconnect_all`
+    - Expose ``mongoengine.connection.disconnect`` and ``mongoengine.connection.disconnect_all``.
-    - Fix disconnecting #566 #1599 #605 #607 #1213 #565
+    - Fix disconnecting. #566 #1599 #605 #607 #1213 #565
-    - Improve documentation of `connect`/`disconnect`
+    - Improve documentation of ``connect``/``disconnect``.
-    - Fix issue when using multiple connections to the same mongo with different credentials #2047
+    - Fix issue when using multiple connections to the same mongo with different credentials. #2047
-    - `connect` fails immediately when db name contains invalid characters #2031 #1718
+    - ``connect`` fails immediately when db name contains invalid characters. #2031 #1718
-- Fix the default write concern of `Document.save` that was overwriting the connection write concern #568
+- Fix the default write concern of ``Document.save`` that was overwriting the connection write concern. #568
-- Fix querying on `List(EmbeddedDocument)` subclasses fields #1961 #1492
+- Fix querying on ``List(EmbeddedDocument)`` subclasses fields. #1961 #1492
-- Fix querying on `(Generic)EmbeddedDocument` subclasses fields #475
+- Fix querying on ``(Generic)EmbeddedDocument`` subclasses fields. #475
-- Fix `QuerySet.aggregate` so that it takes limit and skip value into account #2029
+- Fix ``QuerySet.aggregate`` so that it takes limit and skip value into account. #2029
-- Generate unique indices for `SortedListField` and `EmbeddedDocumentListFields` #2020
+- Generate unique indices for ``SortedListField`` and ``EmbeddedDocumentListFields``. #2020
-- BREAKING CHANGE: Changed the behavior of a custom field validator (i.e `validation` parameter of a `Field`). It is now expected to raise a `ValidationError` instead of returning True/False #2050
+- BREAKING CHANGE: Changed the behavior of a custom field validator (i.e ``validation`` parameter of a ``Field``). It is now expected to raise a ``ValidationError`` instead of returning ``True``/``False``. #2050
-- BREAKING CHANGES (associated with connect/disconnect fixes):
+- BREAKING CHANGES (associated with connection/disconnection fixes):
-    - Calling `connect` 2 times with the same alias and different parameter will raise an error (should call `disconnect` first).
+    - Calling ``connect`` 2 times with the same alias and different parameter will raise an error (should call ``disconnect`` first).
-    - `disconnect` now clears `mongoengine.connection._connection_settings`.
+    - ``disconnect`` now clears ``mongoengine.connection._connection_settings``.
-    - `disconnect` now clears the cached attribute `Document._collection`.
+    - ``disconnect`` now clears the cached attribute ``Document._collection``.
-- BREAKING CHANGE: `EmbeddedDocument.save` & `.reload` is no longier exist #1552
+- BREAKING CHANGE: ``EmbeddedDocument.save`` & ``.reload`` no longer exist. #1552
 
 Changes in 0.17.0
 =================
-- Fix .only() working improperly after using .count() of the same instance of QuerySet
+- POTENTIAL BREAKING CHANGE: All result fields are now passed, including internal fields (``_cls``, ``_id``) when using ``QuerySet.as_pymongo``. #1976
-- Fix batch_size that was not copied when cloning a queryset object #2011
+- Document a BREAKING CHANGE introduced in 0.15.3 and not reported at that time. #1995
-- POTENTIAL BREAKING CHANGE: All result fields are now passed, including internal fields (_cls, _id) when using `QuerySet.as_pymongo` #1976
+- DEPRECATION: ``EmbeddedDocument.save`` & ``.reload`` are marked as deprecated and will be removed in a next version of MongoEngine. #1552
-- Document a BREAKING CHANGE introduced in 0.15.3 and not reported at that time (#1995)
+- Fix ``QuerySet.only`` working improperly after using ``QuerySet.count`` of the same instance of a ``QuerySet``.
-- Fix InvalidStringData error when using modify on a BinaryField #1127
+- Fix ``batch_size`` that was not copied when cloning a ``QuerySet`` object. #2011
-- DEPRECATION: `EmbeddedDocument.save` & `.reload` are marked as deprecated and will be removed in a next version of mongoengine #1552
+- Fix ``InvalidStringData`` error when using ``modify`` on a ``BinaryField``. #1127
-- Fix test suite and CI to support MongoDB 3.4 #1445
+- Fix test suite and CI to support MongoDB v3.4. #1445
-- Fix reference fields querying the database on each access if value contains orphan DBRefs
+- Fix reference fields querying the database on each access if value contains orphan DBRefs.
 
-=================
 Changes in 0.16.3
 =================
-- Fix $push with $position operator not working with lists in embedded document #1965
+- Fix ``$push`` with the ``$position`` operator not working with lists in embedded documents. #1965
 
-=================
 Changes in 0.16.2
 =================
-- Fix .save() that fails when called with write_concern=None (regression of 0.16.1) #1958
+- Fix ``Document.save`` that fails when called with ``write_concern=None`` (regression of 0.16.1). #1958
 
-=================
 Changes in 0.16.1
 =================
-- Fix `_cls` that is not set properly in Document constructor (regression) #1950
+- Fix ``_cls`` that is not set properly in the ``Document`` constructor (regression). #1950
-- Fix bug in _delta method - Update of a ListField depends on an unrelated dynamic field update #1733
+- Fix a bug in the ``_delta`` method - update of a ``ListField`` depends on an unrelated dynamic field update. #1733
-- Remove deprecated `save()` method and used `insert_one()` #1899
+- Remove PyMongo's deprecated ``Collection.save`` method and use ``Collection.insert_one`` instead. #1899
 
-=================
 Changes in 0.16.0
 =================
-- Various improvements to the doc
-- Improvement to code quality
 - POTENTIAL BREAKING CHANGES:
-    - EmbeddedDocumentField will no longer accept references to Document classes in its constructor #1661
+    - ``EmbeddedDocumentField`` will no longer accept references to Document classes in its constructor. #1661
-    - Get rid of the `basecls` parameter from the DictField constructor (dead code) #1876
+    - Get rid of the ``basecls`` parameter from the ``DictField`` constructor (dead code). #1876
-    - default value of ComplexDateTime is now None (and no longer the current datetime) #1368
+    - Default value of the ``ComplexDateTime`` field is now ``None`` (and no longer the current datetime). #1368
-- Fix unhashable TypeError when referencing a Document with a compound key in an EmbeddedDocument #1685
+- Fix an unhashable ``TypeError`` when referencing a ``Document`` with a compound key in an ``EmbeddedDocument``. #1685
-- Fix bug where an EmbeddedDocument with the same id as its parent would not be tracked for changes #1768
+- Fix a bug where an ``EmbeddedDocument`` with the same id as its parent would not be tracked for changes. #1768
-- Fix the fact that bulk `insert()` was not setting primary keys of inserted documents instances #1919
+- Fix the fact that a bulk ``QuerySet.insert`` was not setting primary keys of inserted document instances. #1919
-- Fix bug when referencing the abstract class in a ReferenceField #1920
+- Fix a bug when referencing an abstract class in a ``ReferenceField``. #1920
-- Allow modification to the document made in pre_save_post_validation to be taken into account #1202
+- Allow modifications to the document made in ``pre_save_post_validation`` to be taken into account. #1202
-- Replaced MongoDB 2.4 tests in CI by MongoDB 3.2 #1903
+- Replace MongoDB v2.4 tests in Travis CI with MongoDB v3.2. #1903
-- Fix side effects of using queryset.`no_dereference` on other documents #1677
+- Fix side effects of using ``QuerySet.no_dereference`` on other documents. #1677
-- Fix TypeError when using lazy django translation objects as translated choices #1879
+- Fix ``TypeError`` when using lazy Django translation objects as translated choices. #1879
-- Improve 2-3 codebase compatibility #1889
+- Improve Python 2-3 codebase compatibility. #1889
-- Fix the support for changing the default value of ComplexDateTime #1368
+- Fix support for changing the default value of the ``ComplexDateTime`` field. #1368
-- Improves error message in case an EmbeddedDocumentListField receives an EmbeddedDocument instance
+- Improve error message in case an ``EmbeddedDocumentListField`` receives an ``EmbeddedDocument`` instance instead of a list. #1877
-    instead of a list #1877
+- Fix the ``inc`` and ``dec`` operators for the ``DecimalField``. #1517 #1320
-- Fix the Decimal operator inc/dec #1517 #1320
+- Ignore ``killcursors`` queries in ``query_counter`` context manager. #1869
-- Ignore killcursors queries in `query_counter` context manager #1869
+- Fix the fact that ``query_counter`` was modifying the initial profiling level in case it was != 0. #1870
-- Fix the fact that `query_counter` was modifying the initial profiling_level in case it was != 0 #1870
+- Repair the ``no_sub_classes`` context manager + fix the fact that it was swallowing exceptions. #1865
-- Repaired the `no_sub_classes` context manager + fix the fact that it was swallowing exceptions #1865
+- Fix index creation error that was swallowed by ``hasattr`` under Python 2. #1688
-- Fix index creation error that was swallowed by hasattr under python2 #1688
+- ``QuerySet.limit`` function behaviour: Passing 0 as parameter will return all the documents in the cursor. #1611
-- QuerySet limit function behaviour: Passing 0 as parameter will return all the documents in the cursor #1611
+- Bulk insert updates the IDs of the input documents instances. #1919
-- bulk insert updates the ids of the input documents instances #1919
+- Fix a harmless bug related to ``GenericReferenceField`` where modifications in the generic-referenced document were tracked in the parent. #1934
-- Fix an harmless bug related to GenericReferenceField where modifications in the generic-referenced document
+- Improve validation of the ``BinaryField``. #273
-    were tracked in the parent #1934
+- Implement lazy regex compiling in Field classes to improve ``import mongoengine`` performance. #1806
-- Improve validator of BinaryField #273
+- Update ``GridFSProxy.__str__``  so that it would always print both the filename and grid_id. #710
-- Implemented lazy regex compiling in Field classes to improve 'import mongoengine' performance #1806
+- Add ``__repr__`` to ``Q`` and ``QCombination`` classes. #1843
-- Updated GridFSProxy.__str__  so that it would always print both the filename and grid_id #710
+- Fix bug in the ``BaseList.__iter__`` operator (was occuring when modifying a BaseList while iterating over it). #1676
-- Add __repr__ to Q and QCombination #1843
+- Add a ``DateField``. #513
-- fix bug in BaseList.__iter__ operator (was occuring when modifying a BaseList while iterating over it) #1676
+- Various improvements to the documentation.
-- Added field `DateField`#513
+- Various code quality improvements.
 
 Changes in 0.15.3
 =================
--  BREAKING CHANGES: `Queryset.update/update_one` methods now returns an UpdateResult when `full_result=True` is provided and no longer a dict (relates to #1491)
+- ``Queryset.update/update_one`` methods now return an ``UpdateResult`` when ``full_result=True`` is provided and no longer a dict. #1491
--  Subfield resolve error in generic_emdedded_document query #1651 #1652
+- Improve ``LazyReferenceField`` and ``GenericLazyReferenceField`` with nested fields. #1704
--  use each modifier only with $position #1673 #1675
+- Fix the subfield resolve error in ``generic_emdedded_document`` query. #1651 #1652
--  Improve LazyReferenceField and GenericLazyReferenceField with nested fields #1704
+- Use each modifier only with ``$position``. #1673 #1675
--  Fix validation error instance in GenericEmbeddedDocumentField #1067
+- Fix validation errors in the ``GenericEmbeddedDocumentField``. #1067
--  Update cached fields when fields argument is given #1712
+- Update cached fields when a ``fields`` argument is given. #1712
--  Add a db parameter to register_connection for compatibility with connect
+- Add a ``db`` parameter to ``register_connection`` for compatibility with ``connect``.
--  Use insert_one, insert_many in Document.insert #1491
+- Use PyMongo v3.x's ``insert_one`` and ``insert_many`` in ``Document.insert``. #1491
--  Use new update_one, update_many on document/queryset update #1491
+- Use PyMongo v3.x's ``update_one`` and ``update_many`` in ``Document.update`` and ``QuerySet.update``. #1491
--  Use insert_one, insert_many in Document.insert #1491
+- Fix how ``reload(fields)`` affects changed fields. #1371
--  Fix reload(fields) affect changed fields #1371
+- Fix a bug where the read-only access to the database fails when trying to create indexes. #1338
--  Fix Read-only access to database fails when trying to create indexes #1338
 
 Changes in 0.15.0
 =================
-- Add LazyReferenceField and GenericLazyReferenceField to address #1230
+- Add ``LazyReferenceField`` and ``GenericLazyReferenceField``. #1230
 
 Changes in 0.14.1
 =================
-- Removed SemiStrictDict and started using a regular dict for `BaseDocument._data` #1630
+- Remove ``SemiStrictDict`` and start using a regular dict for ``BaseDocument._data``. #1630
-- Added support for the `$position` param in the `$push` operator #1566
+- Add support for the ``$position`` param in the ``$push`` operator. #1566
-- Fixed `DateTimeField` interpreting an empty string as today #1533
+- Fix ``DateTimeField`` interpreting an empty string as today. #1533
-- Added a missing `__ne__` method to the `GridFSProxy` class #1632
+- Add a missing ``__ne__`` method to the ``GridFSProxy`` class. #1632
-- Fixed `BaseQuerySet._fields_to_db_fields` #1553
+- Fix ``BaseQuerySet._fields_to_db_fields``. #1553
 
 Changes in 0.14.0
 =================
-- BREAKING CHANGE: Removed the `coerce_types` param from `QuerySet.as_pymongo` #1549
+- BREAKING CHANGE: Remove the ``coerce_types`` param from ``QuerySet.as_pymongo``. #1549
-- POTENTIAL BREAKING CHANGE: Made EmbeddedDocument not hashable by default #1528
+- POTENTIAL BREAKING CHANGE: Make ``EmbeddedDocument`` not hashable by default. #1528
-- Improved code quality #1531, #1540, #1541, #1547
+- Improve code quality. #1531, #1540, #1541, #1547
 
 Changes in 0.13.0
 =================
-- POTENTIAL BREAKING CHANGE: Added Unicode support to the `EmailField`, see
+- POTENTIAL BREAKING CHANGE: Added Unicode support to the ``EmailField``, see docs/upgrade.rst for details.
-  docs/upgrade.rst for details.
 
 Changes in 0.12.0
 =================
-- POTENTIAL BREAKING CHANGE: Fixed limit/skip/hint/batch_size chaining #1476
+- POTENTIAL BREAKING CHANGE: Fix ``limit``/``skip``/``hint``/``batch_size`` chaining. #1476
-- POTENTIAL BREAKING CHANGE: Changed a public `QuerySet.clone_into` method to a private `QuerySet._clone_into` #1476
+- POTENTIAL BREAKING CHANGE: Change a public ``QuerySet.clone_into`` method to a private ``QuerySet._clone_into``. #1476
-- Fixed the way `Document.objects.create` works with duplicate IDs #1485
+- Fix the way ``Document.objects.create`` works with duplicate IDs. #1485
-- Fixed connecting to a replica set with PyMongo 2.x #1436
+- Fix connecting to a replica set with PyMongo 2.x. #1436
-- Fixed using sets in field choices #1481
+- Fix using sets in field choices. #1481
-- Fixed deleting items from a `ListField` #1318
+- Fix deleting items from a ``ListField``. #1318
-- Fixed an obscure error message when filtering by `field__in=non_iterable`. #1237
+- Fix an obscure error message when filtering by ``field__in=non_iterable``. #1237
-- Fixed behavior of a `dec` update operator #1450
+- Fix behavior of a ``dec`` update operator. #1450
-- Added a `rename` update operator #1454
+- Add a ``rename`` update operator. #1454
-- Added validation for the `db_field` parameter #1448
+- Add validation for the ``db_field`` parameter. #1448
-- Fixed the error message displayed when querying an `EmbeddedDocumentField` by an invalid value #1440
+- Fix the error message displayed when querying an ``EmbeddedDocumentField`` by an invalid value. #1440
-- Fixed the error message displayed when validating unicode URLs #1486
+- Fix the error message displayed when validating Unicode URLs. #1486
-- Raise an error when trying to save an abstract document #1449
+- Raise an error when trying to save an abstract document. #1449
 
 Changes in 0.11.0
 =================
-- BREAKING CHANGE: Renamed `ConnectionError` to `MongoEngineConnectionError` since the former is a built-in exception name in Python v3.x. #1428
+- BREAKING CHANGE: Rename ``ConnectionError`` to ``MongoEngineConnectionError`` since the former is a built-in exception name in Python v3.x. #1428
-- BREAKING CHANGE: Dropped Python 2.6 support. #1428
+- BREAKING CHANGE: Drop Python v2.6 support. #1428
-- BREAKING CHANGE: `from mongoengine.base import ErrorClass` won't work anymore for any error from `mongoengine.errors` (e.g. `ValidationError`). Use `from mongoengine.errors import ErrorClass instead`. #1428
+- BREAKING CHANGE: ``from mongoengine.base import ErrorClass`` won't work anymore for any error from ``mongoengine.errors`` (e.g. ``ValidationError``). Use ``from mongoengine.errors import ErrorClass instead``. #1428
-- BREAKING CHANGE: Accessing a broken reference will raise a `DoesNotExist` error. In the past it used to return `None`. #1334
+- BREAKING CHANGE: Accessing a broken reference will raise a ``DoesNotExist`` error. In the past it used to return ``None``. #1334
-- Fixed absent rounding for DecimalField when `force_string` is set. #1103
+- Fix absent rounding for the ``DecimalField`` when ``force_string`` is set. #1103
 
 Changes in 0.10.8
 =================
-- Added support for QuerySet.batch_size (#1426)
+- Add support for ``QuerySet.batch_size``. (#1426)
-- Fixed query set iteration within iteration #1427
+- Fix a query set iteration within an iteration. #1427
-- Fixed an issue where specifying a MongoDB URI host would override more information than it should #1421
+- Fix an issue where specifying a MongoDB URI host would override more information than it should. #1421
-- Added ability to filter the generic reference field by ObjectId and DBRef #1425
+- Add an ability to filter the ``GenericReferenceField`` by an ``ObjectId`` and a ``DBRef``. #1425
-- Fixed delete cascade for models with a custom primary key field #1247
+- Fix cascading deletes for models with a custom primary key field. #1247
-- Added ability to specify an authentication mechanism (e.g. X.509) #1333
+- Add ability to specify an authentication mechanism (e.g. X.509). #1333
-- Added support for falsey primary keys (e.g. doc.pk = 0) #1354
+- Add support for falsy primary keys (e.g. ``doc.pk = 0``). #1354
-- Fixed QuerySet#sum/average for fields w/ explicit db_field #1417
+- Fix ``QuerySet.sum/average`` for fields w/ an explicit ``db_field``. #1417
-- Fixed filtering by embedded_doc=None #1422
+- Fix filtering by ``embedded_doc=None``. #1422
-- Added support for cursor.comment #1420
+- Add support for ``Cursor.comment``. #1420
-- Fixed doc.get_<field>_display #1419
+- Fix ``doc.get_<field>_display`` methods. #1419
-- Fixed __repr__ method of the StrictDict #1424
+- Fix the ``__repr__`` method of the ``StrictDict`` #1424
-- Added a deprecation warning for Python 2.6
+- Add a deprecation warning for Python v2.6.
 
 Changes in 0.10.7
 =================
-- Dropped Python 3.2 support #1390
+- Drop Python 3.2 support #1390
-- Fixed the bug where dynamic doc has index inside a dict field #1278
+- Fix a bug where a dynamic doc has an index inside a dict field. #1278
-- Fixed: ListField minus index assignment does not work #1128
+- Fix: ``ListField`` minus index assignment does not work. #1128
-- Fixed cascade delete mixing among collections #1224
+- Fix cascade delete mixing among collections. #1224
-- Add `signal_kwargs` argument to `Document.save`, `Document.delete` and `BaseQuerySet.insert` to be passed to signals calls #1206
+- Add ``signal_kwargs`` argument to ``Document.save``, ``Document.delete`` and ``BaseQuerySet.insert`` to be passed to signals calls. #1206
-- Raise `OperationError` when trying to do a `drop_collection` on document with no collection set.
+- Raise ``OperationError`` when trying to do a ``drop_collection`` on document with no collection set.
-- count on ListField of EmbeddedDocumentField fails. #1187
+- Fix a bug where a count on ``ListField`` of ``EmbeddedDocumentField`` fails. #1187
-- Fixed long fields stored as int32 in Python 3. #1253
+- Fix ``LongField`` values stored as int32 in Python 3. #1253
-- MapField now handles unicodes keys correctly. #1267
+- ``MapField`` now handles unicode keys correctly. #1267
-- ListField now handles negative indicies correctly. #1270
+- ``ListField`` now handles negative indicies correctly. #1270
-- Fixed AttributeError when initializing EmbeddedDocument with positional args. #681
+- Fix an ``AttributeError`` when initializing an ``EmbeddedDocument`` with positional args. #681
-- Fixed no_cursor_timeout error with pymongo 3.0+ #1304
+- Fix a ``no_cursor_timeout`` error with PyMongo v3.x. #1304
-- Replaced map-reduce based QuerySet.sum/average with aggregation-based implementations #1336
+- Replace map-reduce based ``QuerySet.sum/average`` with aggregation-based implementations. #1336
-- Fixed support for `__` to escape field names that match operators names in `update` #1351
+- Fix support for ``__`` to escape field names that match operators' names in ``update``. #1351
-- Fixed BaseDocument#_mark_as_changed #1369
+- Fix ``BaseDocument._mark_as_changed``. #1369
-- Added support for pickling QuerySet instances. #1397
+- Add support for pickling ``QuerySet`` instances. #1397
-- Fixed connecting to a list of hosts #1389
+- Fix connecting to a list of hosts. #1389
-- Fixed a bug where accessing broken references wouldn't raise a DoesNotExist error #1334
+- Fix a bug where accessing broken references wouldn't raise a ``DoesNotExist`` error. #1334
-- Fixed not being able to specify use_db_field=False on ListField(EmbeddedDocumentField) instances #1218
+- Fix not being able to specify ``use_db_field=False`` on ``ListField(EmbeddedDocumentField)`` instances. #1218
-- Improvements to the dictionary fields docs #1383
+- Improvements to the dictionary field's docs. #1383
 
 Changes in 0.10.6
 =================
 - Add support for mocking MongoEngine based on mongomock. #1151
-- Fixed not being able to run tests on Windows. #1153
+- Fix not being able to run tests on Windows. #1153
 - Allow creation of sparse compound indexes. #1114
-- count on ListField of EmbeddedDocumentField fails. #1187
 
 Changes in 0.10.5
 =================
@@ -215,12 +271,12 @@ Changes in 0.10.5
 
 Changes in 0.10.4
 =================
-- SaveConditionError is now importable from the top level package. #1165
+- ``SaveConditionError`` is now importable from the top level package. #1165
-- upsert_one method added. #1157
+- Add a ``QuerySet.upsert_one`` method. #1157
 
 Changes in 0.10.3
 =================
-- Fix `read_preference` (it had chaining issues with PyMongo 2.x and it didn't work at all with PyMongo 3.x) #1042
+- Fix ``read_preference`` (it had chaining issues with PyMongo v2.x and it didn't work at all with PyMongo v3.x). #1042
 
 Changes in 0.10.2
 =================
@@ -230,16 +286,16 @@ Changes in 0.10.2
 
 Changes in 0.10.1
 =================
-- Fix infinite recursion with CASCADE delete rules under specific conditions. #1046
+- Fix infinite recursion with cascade delete rules under specific conditions. #1046
-- Fix CachedReferenceField bug when loading cached docs as DBRef but failing to save them. #1047
+- Fix ``CachedReferenceField`` bug when loading cached docs as ``DBRef`` but failing to save them. #1047
-- Fix ignored chained options #842
+- Fix ignored chained options. #842
-- Document save's save_condition error raises `SaveConditionError` exception #1070
+- ``Document.save``'s ``save_condition`` error raises a ``SaveConditionError`` exception. #1070
-- Fix Document.reload for DynamicDocument. #1050
+- Fix ``Document.reload`` for the ``DynamicDocument``. #1050
-- StrictDict & SemiStrictDict are shadowed at init time. #1105
+- ``StrictDict`` & ``SemiStrictDict`` are shadowed at init time. #1105
-- Fix ListField minus index assignment does not work. #1119
+- Fix ``ListField`` negative index assignment not working. #1119
-- Remove code that marks field as changed when the field has default but not existed in database #1126
+- Remove code that marks a field as changed when the field has a default value but does not exist in the database. #1126
-- Remove test dependencies (nose and rednose) from install dependencies list. #1079
+- Remove test dependencies (nose and rednose) from install dependencies. #1079
-- Recursively build query when using elemMatch operator. #1130
+- Recursively build a query when using the ``elemMatch`` operator. #1130
 - Fix instance back references for lists of embedded documents. #1131
 
 Changes in 0.10.0
@@ -250,7 +306,7 @@ Changes in 0.10.0
 - Removed get_or_create() deprecated since 0.8.0. #300
 - Improve Document._created status when switch collection and db #1020
 - Queryset update doesn't go through field validation #453
-- Added support for specifying authentication source as option `authSource` in URI. #967
+- Added support for specifying authentication source as option ``authSource`` in URI. #967
 - Fixed mark_as_changed to handle higher/lower level fields changed. #927
 - ListField of embedded docs doesn't set the _instance attribute when iterating over it #914
 - Support += and *= for ListField #595
@@ -266,7 +322,7 @@ Changes in 0.10.0
 - Fixes some internal _id handling issue. #961
 - Updated URL and Email Field regex validators, added schemes argument to URLField validation. #652
 - Capped collection multiple of 256. #1011
-- Added `BaseQuerySet.aggregate_sum` and `BaseQuerySet.aggregate_average` methods.
+- Added ``BaseQuerySet.aggregate_sum`` and ``BaseQuerySet.aggregate_average`` methods.
 - Fix for delete with write_concern {'w': 0}. #1008
 - Allow dynamic lookup for more than two parts. #882
 - Added support for min_distance on geo queries. #831
@@ -275,10 +331,10 @@ Changes in 0.10.0
 Changes in 0.9.0
 ================
 - Update FileField when creating a new file #714
-- Added `EmbeddedDocumentListField` for Lists of Embedded Documents. #826
+- Added ``EmbeddedDocumentListField`` for Lists of Embedded Documents. #826
 - ComplexDateTimeField should fall back to None when null=True #864
 - Request Support for $min, $max Field update operators #863
-- `BaseDict` does not follow `setdefault` #866
+- ``BaseDict`` does not follow ``setdefault`` #866
 - Add support for $type operator # 766
 - Fix tests for pymongo 2.8+ #877
 - No module named 'django.utils.importlib' (Django dev) #872
@@ -299,13 +355,13 @@ Changes in 0.9.0
 - Stop ensure_indexes running on a secondaries unless connection is through mongos #746
 - Not overriding default values when loading a subset of fields #399
 - Saving document doesn't create new fields in existing collection #620
-- Added `Queryset.aggregate` wrapper to aggregation framework #703
+- Added ``Queryset.aggregate`` wrapper to aggregation framework #703
 - Added support to show original model fields on to_json calls instead of db_field #697
 - Added Queryset.search_text to Text indexes searchs #700
 - Fixed tests for Django 1.7 #696
 - Follow ReferenceFields in EmbeddedDocuments with select_related #690
 - Added preliminary support for text indexes #680
-- Added `elemMatch` operator as well - `match` is too obscure #653
+- Added ``elemMatch`` operator as well - ``match`` is too obscure #653
 - Added support for progressive JPEG #486 #548
 - Allow strings to be used in index creation #675
 - Fixed EmbeddedDoc weakref proxy issue #592
@@ -341,11 +397,11 @@ Changes in 0.9.0
 - Increase email field length to accommodate new TLDs #726
 - index_cls is ignored when deciding to set _cls as index prefix #733
 - Make 'db' argument to connection optional #737
-- Allow atomic update for the entire `DictField` #742
+- Allow atomic update for the entire ``DictField`` #742
 - Added MultiPointField, MultiLineField, MultiPolygonField
 - Fix multiple connections aliases being rewritten #748
 - Fixed a few instances where reverse_delete_rule was written as reverse_delete_rules. #791
-- Make `in_bulk()` respect `no_dereference()` #775
+- Make ``in_bulk()`` respect ``no_dereference()`` #775
 - Handle None from model __str__; Fixes #753 #754
 - _get_changed_fields fix for embedded documents with id field. #925
 
@@ -399,18 +455,15 @@ Changes in 0.8.4
 
 Changes in 0.8.3
 ================
-- Fixed EmbeddedDocuments with `id` also storing `_id` (#402)
+- Fixed EmbeddedDocuments with ``id`` also storing ``_id`` (#402)
 - Added get_proxy_object helper to filefields (#391)
 - Added QuerySetNoCache and QuerySet.no_cache() for lower memory consumption (#365)
 - Fixed sum and average mapreduce dot notation support (#375, #376, #393)
 - Fixed as_pymongo to return the id (#386)
-- Document.select_related() now respects `db_alias` (#377)
+- Document.select_related() now respects ``db_alias`` (#377)
 - Reload uses shard_key if applicable (#384)
 - Dynamic fields are ordered based on creation and stored in _fields_ordered (#396)
-
+- Fixed pickling dynamic documents ``_dynamic_fields`` (#387)
-  **Potential breaking change:** http://docs.mongoengine.org/en/latest/upgrade.html#to-0-8-3
-
-- Fixed pickling dynamic documents `_dynamic_fields` (#387)
 - Fixed ListField setslice and delslice dirty tracking (#390)
 - Added Django 1.5 PY3 support (#392)
 - Added match ($elemMatch) support for EmbeddedDocuments (#379)
@@ -451,7 +504,7 @@ Changes in 0.8.0
 ================
 - Fixed querying ReferenceField custom_id (#317)
 - Fixed pickle issues with collections (#316)
-- Added `get_next_value` preview for SequenceFields (#319)
+- Added ``get_next_value`` preview for SequenceFields (#319)
 - Added no_sub_classes context manager and queryset helper (#312)
 - Querysets now utilises a local cache
 - Changed __len__ behaviour in the queryset (#247, #311)
@@ -480,7 +533,7 @@ Changes in 0.8.0
 - Updated connection to use MongoClient (#262, #274)
 - Fixed db_alias and inherited Documents (#143)
 - Documentation update for document errors (#124)
-- Deprecated `get_or_create` (#35)
+- Deprecated ``get_or_create`` (#35)
 - Updated inheritable objects created by upsert now contain _cls (#118)
 - Added support for creating documents with embedded documents in a single operation (#6)
 - Added to_json and from_json to Document (#1)
@@ -601,7 +654,7 @@ Changes in 0.7.0
 - Fixed UnboundLocalError in composite index with pk field (#88)
 - Updated ReferenceField's to optionally store ObjectId strings
   this will become the default in 0.8 (#89)
-- Added FutureWarning - save will default to `cascade=False` in 0.8
+- Added FutureWarning - save will default to ``cascade=False`` in 0.8
 - Added example of indexing embedded document fields (#75)
 - Fixed ImageField resizing when forcing size (#80)
 - Add flexibility for fields handling bad data (#78)
@@ -697,7 +750,7 @@ Changes in 0.6.8
 ================
 - Fixed FileField losing reference when no default set
 - Removed possible race condition from FileField (grid_file)
-- Added assignment to save, can now do: `b = MyDoc(**kwargs).save()`
+- Added assignment to save, can now do: ``b = MyDoc(**kwargs).save()``
 - Added support for pull operations on nested EmbeddedDocuments
 - Added support for choices with GenericReferenceFields
 - Added support for choices with GenericEmbeddedDocumentFields
@@ -712,7 +765,7 @@ Changes in 0.6.7
 - Fixed indexing on '_id' or 'pk' or 'id'
 - Invalid data from the DB now raises a InvalidDocumentError
 - Cleaned up the Validation Error - docs and code
-- Added meta `auto_create_index` so you can disable index creation
+- Added meta ``auto_create_index`` so you can disable index creation
 - Added write concern options to inserts
 - Fixed typo in meta for index options
 - Bug fix Read preference now passed correctly
@@ -753,7 +806,6 @@ Changes in 0.6.1
 
 Changes in 0.6
 ==============
-
 - Added FutureWarning to inherited classes not declaring 'allow_inheritance' as the default will change in 0.7
 - Added support for covered indexes when inheritance is off
 - No longer always upsert on save for items with a '_id'
@@ -978,7 +1030,6 @@ Changes in v0.1.3
   querying takes place
 - A few minor bugfixes
 
-
 Changes in v0.1.2
 =================
 - Query values may be processed before before being used in queries
@@ -987,7 +1038,6 @@ Changes in v0.1.2
 - Added ``BooleanField``
 - Added ``Document.reload()`` method
 
-
 Changes in v0.1.1
 =================
 - Documents may now use capped collections

docs/code/tumblelog.py

@@ -1,16 +1,19 @@
 from mongoengine import *
 
-connect('tumblelog')
+connect("tumblelog")
+
 
 class Comment(EmbeddedDocument):
     content = StringField()
     name = StringField(max_length=120)
 
+
 class User(Document):
     email = StringField(required=True)
     first_name = StringField(max_length=50)
     last_name = StringField(max_length=50)
 
+
 class Post(Document):
     title = StringField(max_length=120, required=True)
     author = ReferenceField(User)
@@ -18,54 +21,57 @@ class Post(Document):
     comments = ListField(EmbeddedDocumentField(Comment))
 
     # bugfix
-    meta = {'allow_inheritance': True}
+    meta = {"allow_inheritance": True}
 
 
 class TextPost(Post):
     content = StringField()
 
+
 class ImagePost(Post):
     image_path = StringField()
 
+
 class LinkPost(Post):
     link_url = StringField()
 
+
 Post.drop_collection()
 
-john = User(email='jdoe@example.com', first_name='John', last_name='Doe')
+john = User(email="jdoe@example.com", first_name="John", last_name="Doe")
 john.save()
 
-post1 = TextPost(title='Fun with MongoEngine', author=john)
+post1 = TextPost(title="Fun with MongoEngine", author=john)
-post1.content = 'Took a look at MongoEngine today, looks pretty cool.'
+post1.content = "Took a look at MongoEngine today, looks pretty cool."
-post1.tags = ['mongodb', 'mongoengine']
+post1.tags = ["mongodb", "mongoengine"]
 post1.save()
 
-post2 = LinkPost(title='MongoEngine Documentation', author=john)
+post2 = LinkPost(title="MongoEngine Documentation", author=john)
-post2.link_url = 'http://tractiondigital.com/labs/mongoengine/docs'
+post2.link_url = "http://tractiondigital.com/labs/mongoengine/docs"
-post2.tags = ['mongoengine']
+post2.tags = ["mongoengine"]
 post2.save()
 
-print('ALL POSTS')
+print("ALL POSTS")
 print()
 for post in Post.objects:
     print(post.title)
-    #print '=' * post.title.count()
+    # print '=' * post.title.count()
     print("=" * 20)
 
     if isinstance(post, TextPost):
         print(post.content)
 
     if isinstance(post, LinkPost):
-        print('Link:', post.link_url)
+        print("Link:", post.link_url)
 
     print()
 print()
 
-print('POSTS TAGGED \'MONGODB\'')
+print("POSTS TAGGED 'MONGODB'")
 print()
-for post in Post.objects(tags='mongodb'):
+for post in Post.objects(tags="mongodb"):
     print(post.title)
 print()
 
-num_posts = Post.objects(tags='mongodb').count()
+num_posts = Post.objects(tags="mongodb").count()
 print('Found %d posts with tag "mongodb"' % num_posts)

docs/conf.py

@@ -11,7 +11,8 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-import sys, os
+import os
+import sys
 
 import sphinx_rtd_theme
 
@@ -20,29 +21,29 @@ import mongoengine
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
-sys.path.insert(0, os.path.abspath('..'))
+sys.path.insert(0, os.path.abspath(".."))
 
 # -- General configuration -----------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinx.ext.autodoc', 'sphinx.ext.todo']
+extensions = ["sphinx.ext.autodoc", "sphinx.ext.todo"]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
-#source_encoding = 'utf-8'
+# source_encoding = 'utf-8'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = u'MongoEngine'
+project = u"MongoEngine"
-copyright = u'2009, MongoEngine Authors'
+copyright = u"2009, MongoEngine Authors"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -55,68 +56,66 @@ release = mongoengine.get_version()
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
-#language = None
+# language = None
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
-#today = ''
+# today = ''
 # Else, today_fmt is used as the format for a strftime call.
-#today_fmt = '%B %d, %Y'
+# today_fmt = '%B %d, %Y'
 
 # List of documents that shouldn't be included in the build.
-#unused_docs = []
+# unused_docs = []
 
 # List of directories, relative to source directory, that shouldn't be searched
 # for source files.
-exclude_trees = ['_build']
+exclude_trees = ["_build"]
 
 # The reST default role (used for this markup: `text`) to use for all documents.
-#default_role = None
+# default_role = None
 
 # If true, '()' will be appended to :func: etc. cross-reference text.
-#add_function_parentheses = True
+# add_function_parentheses = True
 
 # If true, the current module name will be prepended to all description
 # unit titles (such as .. function::).
-#add_module_names = True
+# add_module_names = True
 
 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
-#show_authors = False
+# show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # A list of ignored prefixes for module index sorting.
-#modindex_common_prefix = []
+# modindex_common_prefix = []
 
 
 # -- Options for HTML output ---------------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  Major themes that come with
 # Sphinx are currently 'default' and 'sphinxdoc'.
-html_theme = 'sphinx_rtd_theme'
+html_theme = "sphinx_rtd_theme"
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-html_theme_options = {
+html_theme_options = {"canonical_url": "http://docs.mongoengine.org/en/latest/"}
-    'canonical_url': 'http://docs.mongoengine.org/en/latest/'
-}
 
 # Add any paths that contain custom themes here, relative to this directory.
 html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-#html_title = None
+# html_title = None
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
-#html_short_title = None
+# html_short_title = None
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-#html_logo = None
+# html_logo = None
 
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
@@ -126,11 +125,11 @@ html_favicon = "favicon.ico"
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-#html_static_path = ['_static']
+# html_static_path = ['_static']
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-#html_last_updated_fmt = '%b %d, %Y'
+# html_last_updated_fmt = '%b %d, %Y'
 
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
@@ -138,69 +137,68 @@ html_use_smartypants = True
 
 # Custom sidebar templates, maps document names to template names.
 html_sidebars = {
-    'index': ['globaltoc.html', 'searchbox.html'],
+    "index": ["globaltoc.html", "searchbox.html"],
-    '**': ['localtoc.html', 'relations.html', 'searchbox.html']
+    "**": ["localtoc.html", "relations.html", "searchbox.html"],
 }
 
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-#html_additional_pages = {}
+# html_additional_pages = {}
 
 # If false, no module index is generated.
-#html_use_modindex = True
+# html_use_modindex = True
 
 # If false, no index is generated.
-#html_use_index = True
+# html_use_index = True
 
 # If true, the index is split into individual pages for each letter.
-#html_split_index = False
+# html_split_index = False
 
 # If true, links to the reST sources are added to the pages.
-#html_show_sourcelink = True
+# html_show_sourcelink = True
 
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-#html_use_opensearch = ''
+# html_use_opensearch = ''
 
 # If nonempty, this is the file name suffix for HTML files (e.g. ".xhtml").
-#html_file_suffix = ''
+# html_file_suffix = ''
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'MongoEnginedoc'
+htmlhelp_basename = "MongoEnginedoc"
 
 
 # -- Options for LaTeX output --------------------------------------------------
 
 # The paper size ('letter' or 'a4').
-latex_paper_size = 'a4'
+latex_paper_size = "a4"
 
 # The font size ('10pt', '11pt' or '12pt').
-#latex_font_size = '10pt'
+# latex_font_size = '10pt'
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
 latex_documents = [
-  ('index', 'MongoEngine.tex', 'MongoEngine Documentation',
+    ("index", "MongoEngine.tex", "MongoEngine Documentation", "Ross Lawley", "manual")
-   'Ross Lawley', 'manual'),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
-#latex_logo = None
+# latex_logo = None
 
 # For "manual" documents, if this is true, then toplevel headings are parts,
 # not chapters.
-#latex_use_parts = False
+# latex_use_parts = False
 
 # Additional stuff for the LaTeX preamble.
-#latex_preamble = ''
+# latex_preamble = ''
 
 # Documents to append as an appendix to all manuals.
-#latex_appendices = []
+# latex_appendices = []
 
 # If false, no module index is generated.
-#latex_use_modindex = True
+# latex_use_modindex = True
 
-autoclass_content = 'both'
+autoclass_content = "both"

docs/faq.rst

@@ -0,0 +1,12 @@
+==========================
+Frequently Asked Questions
+==========================
+
+Does MongoEngine support asynchronous drivers (Motor, TxMongo)?
+---------------------------------------------------------------
+
+No, MongoEngine is exclusively based on PyMongo and isn't designed to support other driver.
+If this is a requirement for your project, check the alternative:  `uMongo`_ and `MotorEngine`_.
+
+.. _uMongo: https://umongo.readthedocs.io/
+.. _MotorEngine: https://motorengine.readthedocs.io/

docs/guide/defining-documents.rst

@@ -352,7 +352,7 @@ Its value can take any of the following constants:
   Deletion is denied if there still exist references to the object being
   deleted.
 :const:`mongoengine.NULLIFY`
-  Any object's fields still referring to the object being deleted are removed
+  Any object's fields still referring to the object being deleted are set to None
   (using MongoDB's "unset" operation), effectively nullifying the relationship.
 :const:`mongoengine.CASCADE`
   Any object containing fields that are referring to the object being deleted
@@ -555,7 +555,6 @@ There are a few top level defaults for all indexes that can be set::
             'index_background': True,
             'index_cls': False,
             'auto_create_index': True,
-            'index_drop_dups': True,
         }
 
 
@@ -574,11 +573,6 @@ There are a few top level defaults for all indexes that can be set::
     in systems where indexes are managed separately. Disabling this will improve
     performance.
 
-:attr:`index_drop_dups` (Optional)
-    Set the default value for if an index should drop duplicates
-    Since MongoDB 3.0 drop_dups is not supported anymore. Raises a Warning
-    and has no effect
-
 
 Compound Indexes and Indexing sub documents
 -------------------------------------------
@@ -714,11 +708,16 @@ subsequent calls to :meth:`~mongoengine.queryset.QuerySet.order_by`. ::
 Shard keys
 ==========
 
-If your collection is sharded, then you need to specify the shard key as a tuple,
+If your collection is sharded by multiple keys, then you can improve shard
-using the :attr:`shard_key` attribute of :attr:`~mongoengine.Document.meta`.
+routing (and thus the performance of your application) by specifying the shard
-This ensures that the shard key is sent with the query when calling the
+key, using the :attr:`shard_key` attribute of
-:meth:`~mongoengine.document.Document.save` or
+:attr:`~mongoengine.Document.meta`. The shard key should be defined as a tuple.
-:meth:`~mongoengine.document.Document.update` method on an existing
+
+This ensures that the full shard key is sent with the query when calling
+methods such as :meth:`~mongoengine.document.Document.save`,
+:meth:`~mongoengine.document.Document.update`,
+:meth:`~mongoengine.document.Document.modify`, or
+:meth:`~mongoengine.document.Document.delete` on an existing
 :class:`~mongoengine.Document` instance::
 
     class LogEntry(Document):
@@ -728,7 +727,8 @@ This ensures that the shard key is sent with the query when calling the
         data = StringField()
 
         meta = {
-            'shard_key': ('machine', 'timestamp',)
+            'shard_key': ('machine', 'timestamp'),
+            'indexes': ('machine', 'timestamp'),
         }
 
 .. _document-inheritance:
@@ -738,7 +738,7 @@ Document inheritance
 
 To create a specialised type of a :class:`~mongoengine.Document` you have
 defined, you may subclass it and add any extra fields or methods you may need.
-As this is new class is not a direct subclass of
+As this new class is not a direct subclass of
 :class:`~mongoengine.Document`, it will not be stored in its own collection; it
 will use the same collection as its superclass uses. This allows for more
 convenient and efficient retrieval of related documents -- all you need do is
@@ -761,6 +761,27 @@ document.::
           Setting :attr:`allow_inheritance` to True should also be used in
           :class:`~mongoengine.EmbeddedDocument` class in case you need to subclass it
 
+When it comes to querying using :attr:`.objects()`, querying `Page.objects()` will query
+both `Page` and `DatedPage` whereas querying `DatedPage` will only query the `DatedPage` documents.
+Behind the scenes, MongoEngine deals with inheritance by adding a :attr:`_cls` attribute that contains
+the class name in every documents. When a document is loaded, MongoEngine checks
+it's :attr:`_cls` attribute and use that class to construct the instance.::
+
+    Page(title='a funky title').save()
+    DatedPage(title='another title', date=datetime.utcnow()).save()
+
+    print(Page.objects().count())         # 2
+    print(DatedPage.objects().count())    # 1
+
+    # print documents in their native form
+    # we remove 'id' to avoid polluting the output with unnecessary detail
+    qs = Page.objects.exclude('id').as_pymongo()
+    print(list(qs))
+    # [
+    #   {'_cls': u 'Page', 'title': 'a funky title'},
+    #   {'_cls': u 'Page.DatedPage', 'title': u 'another title', 'date': datetime.datetime(2019, 12, 13, 20, 16, 59, 993000)}
+    # ]
+
 Working with existing data
 --------------------------
 As MongoEngine no longer defaults to needing :attr:`_cls`, you can quickly and

docs/guide/gridfs.rst

@@ -10,8 +10,9 @@ Writing
 GridFS support comes in the form of the :class:`~mongoengine.fields.FileField` field
 object. This field acts as a file-like object and provides a couple of
 different ways of inserting and retrieving data. Arbitrary metadata such as
-content type can also be stored alongside the files. In the following example,
+content type can also be stored alongside the files. The object returned when accessing a
-a document is created to store details about animals, including a photo::
+FileField is a proxy to `Pymongo's GridFS <https://api.mongodb.com/python/current/examples/gridfs.html#gridfs-example>`_
+In the following example, a document is created to store details about animals, including a photo::
 
     class Animal(Document):
         genus = StringField()
@@ -20,8 +21,8 @@ a document is created to store details about animals, including a photo::
 
     marmot = Animal(genus='Marmota', family='Sciuridae')
 
-    marmot_photo = open('marmot.jpg', 'rb')
+    with open('marmot.jpg', 'rb') as fd:
-    marmot.photo.put(marmot_photo, content_type = 'image/jpeg')
+        marmot.photo.put(fd, content_type = 'image/jpeg')
     marmot.save()
 
 Retrieval
@@ -34,6 +35,20 @@ field. The file can also be retrieved just as easily::
     photo = marmot.photo.read()
     content_type = marmot.photo.content_type
 
+.. note:: If you need to read() the content of a file multiple times, you'll need to "rewind"
+    the file-like object using `seek`::
+
+        marmot = Animal.objects(genus='Marmota').first()
+        content1 = marmot.photo.read()
+        assert content1 != ""
+
+        content2 = marmot.photo.read()    # will be empty
+        assert content2 == ""
+
+        marmot.photo.seek(0)              # rewind the file by setting the current position of the cursor in the file to 0
+        content3 = marmot.photo.read()
+        assert content3 == content1
+
 Streaming
 ---------
 

docs/guide/index.rst

@@ -14,4 +14,5 @@ User Guide
    gridfs
    signals
    text-indexes
+   logging-monitoring
    mongomock

docs/guide/installing.rst

@@ -12,7 +12,7 @@ MongoEngine is available on PyPI, so you can use :program:`pip`:
 
 .. code-block:: console
 
-    $ pip install mongoengine
+    $ python -m pip install mongoengine
 
 Alternatively, if you don't have setuptools installed, `download it from PyPi
 <http://pypi.python.org/pypi/mongoengine/>`_ and run

docs/guide/logging-monitoring.rst

@@ -0,0 +1,80 @@
+==================
+Logging/Monitoring
+==================
+
+It is possible to use `pymongo.monitoring <https://api.mongodb.com/python/current/api/pymongo/monitoring.html>`_ to monitor
+the driver events (e.g: queries, connections, etc). This can be handy if you want to monitor the queries issued by
+MongoEngine to the driver.
+
+To use `pymongo.monitoring` with MongoEngine, you need to make sure that you are registering the listeners
+**before** establishing the database connection (i.e calling `connect`):
+
+The following snippet provides a basic logging of all command events:
+
+.. code-block:: python
+
+    import logging
+    from pymongo import monitoring
+    from mongoengine import *
+
+    log = logging.getLogger()
+    log.setLevel(logging.DEBUG)
+    logging.basicConfig(level=logging.DEBUG)
+
+
+    class CommandLogger(monitoring.CommandListener):
+
+        def started(self, event):
+            log.debug("Command {0.command_name} with request id "
+                     "{0.request_id} started on server "
+                     "{0.connection_id}".format(event))
+
+        def succeeded(self, event):
+            log.debug("Command {0.command_name} with request id "
+                     "{0.request_id} on server {0.connection_id} "
+                     "succeeded in {0.duration_micros} "
+                     "microseconds".format(event))
+
+        def failed(self, event):
+            log.debug("Command {0.command_name} with request id "
+                     "{0.request_id} on server {0.connection_id} "
+                     "failed in {0.duration_micros} "
+                     "microseconds".format(event))
+
+    monitoring.register(CommandLogger())
+
+
+    class Jedi(Document):
+        name = StringField()
+
+
+    connect()
+
+
+    log.info('GO!')
+
+    log.info('Saving an item through MongoEngine...')
+    Jedi(name='Obi-Wan Kenobii').save()
+
+    log.info('Querying through MongoEngine...')
+    obiwan = Jedi.objects.first()
+
+    log.info('Updating through MongoEngine...')
+    obiwan.name = 'Obi-Wan Kenobi'
+    obiwan.save()
+
+
+Executing this prints the following output::
+
+    INFO:root:GO!
+    INFO:root:Saving an item through MongoEngine...
+    DEBUG:root:Command insert with request id 1681692777 started on server ('localhost', 27017)
+    DEBUG:root:Command insert with request id 1681692777 on server ('localhost', 27017) succeeded in 562 microseconds
+    INFO:root:Querying through MongoEngine...
+    DEBUG:root:Command find with request id 1714636915 started on server ('localhost', 27017)
+    DEBUG:root:Command find with request id 1714636915 on server ('localhost', 27017) succeeded in 341 microseconds
+    INFO:root:Updating through MongoEngine...
+    DEBUG:root:Command update with request id 1957747793 started on server ('localhost', 27017)
+    DEBUG:root:Command update with request id 1957747793 on server ('localhost', 27017) succeeded in 455 microseconds
+
+More details can of course be obtained by checking the `event` argument from the `CommandListener`.

docs/guide/mongomock.rst

@@ -21,7 +21,7 @@ or with an alias:
     conn = get_connection('testdb')
 
 Example of test file:
---------
+---------------------
 .. code-block:: python
 
     import unittest
@@ -45,4 +45,4 @@ Example of test file:
             pers.save()
 
             fresh_pers = Person.objects().first()
-            self.assertEqual(fresh_pers.name, 'John')
+            assert fresh_pers.name ==  'John'

docs/guide/querying.rst

@@ -222,6 +222,18 @@ keyword argument::
 
 .. versionadded:: 0.4
 
+Sorting/Ordering results
+========================
+It is possible to order the results by 1 or more keys using :meth:`~mongoengine.queryset.QuerySet.order_by`.
+The order may be specified by prepending each of the keys by "+" or "-". Ascending order is assumed if there's no prefix.::
+
+    # Order by ascending date
+    blogs = BlogPost.objects().order_by('date')    # equivalent to .order_by('+date')
+
+    # Order by ascending date first, then descending title
+    blogs = BlogPost.objects().order_by('+date', '-title')
+
+
 Limiting and skipping results
 =============================
 Just as with traditional ORMs, you may limit the number of results returned or
@@ -349,9 +361,9 @@ Just as with limiting and skipping results, there is a method on a
 You could technically use ``len(User.objects)`` to get the same result, but it
 would be significantly slower than :meth:`~mongoengine.queryset.QuerySet.count`.
 When you execute a server-side count query, you let MongoDB do the heavy
-lifting and you receive a single integer over the wire. Meanwhile, len()
+lifting and you receive a single integer over the wire. Meanwhile, ``len()``
 retrieves all the results, places them in a local cache, and finally counts
-them. If we compare the performance of the two operations, len() is much slower
+them. If we compare the performance of the two operations, ``len()`` is much slower
 than :meth:`~mongoengine.queryset.QuerySet.count`.
 
 Further aggregation
@@ -386,6 +398,25 @@ would be generating "tag-clouds"::
     top_tags = sorted(tag_freqs.items(), key=itemgetter(1), reverse=True)[:10]
 
 
+MongoDB aggregation API
+-----------------------
+If you need to run aggregation pipelines, MongoEngine provides an entry point to `Pymongo's aggregation framework <https://api.mongodb.com/python/current/examples/aggregation.html#aggregation-framework>`_
+through :meth:`~mongoengine.queryset.QuerySet.aggregate`. Check out Pymongo's documentation for the syntax and pipeline.
+An example of its use would be::
+
+        class Person(Document):
+            name = StringField()
+
+        Person(name='John').save()
+        Person(name='Bob').save()
+
+        pipeline = [
+            {"$sort" : {"name" : -1}},
+            {"$project": {"_id": 0, "name": {"$toUpper": "$name"}}}
+            ]
+        data = Person.objects().aggregate(pipeline)
+        assert data == [{'name': 'BOB'}, {'name': 'JOHN'}]
+
 Query efficiency and performance
 ================================
 
@@ -578,7 +609,7 @@ to push values with index::
 .. note::
     Currently only top level lists are handled, future versions of mongodb /
     pymongo plan to support nested positional operators.  See `The $ positional
-    operator <http://www.mongodb.org/display/DOCS/Updating#Updating-The%24positionaloperator>`_.
+    operator <https://docs.mongodb.com/manual/tutorial/update-documents/#Updating-The%24positionaloperator>`_.
 
 Server-side javascript execution
 ================================

docs/index.rst

@@ -7,7 +7,7 @@ MongoDB. To install it, simply run
 
 .. code-block:: console
 
-    $ pip install -U mongoengine
+    $ python -m pip install -U mongoengine
 
 :doc:`tutorial`
   A quick tutorial building a tumblelog to get you up and running with
@@ -23,9 +23,18 @@ MongoDB. To install it, simply run
 :doc:`upgrade`
   How to upgrade MongoEngine.
 
+:doc:`faq`
+  Frequently Asked Questions
+
 :doc:`django`
   Using MongoEngine and Django
 
+MongoDB and driver support
+--------------------------
+
+MongoEngine is based on the PyMongo driver and tested against multiple versions of MongoDB.
+For further details, please refer to the `readme <https://github.com/MongoEngine/mongoengine#mongoengine>`_.
+
 Community
 ---------
 
@@ -73,6 +82,7 @@ formats for offline reading.
     apireference
     changelog
     upgrade
+    faq
     django
 
 Indices and tables
@@ -81,4 +91,3 @@ Indices and tables
 * :ref:`genindex`
 * :ref:`modindex`
 * :ref:`search`
-

docs/tutorial.rst

@@ -18,7 +18,7 @@ location --- running it locally will be easier, but if that is not an option
 then it may be run on a remote server. If you haven't installed MongoEngine,
 simply use pip to install it like so::
 
-    $ pip install mongoengine
+    $ python -m pip install mongoengine
 
 Before we can start using MongoEngine, we need to tell it how to connect to our
 instance of :program:`mongod`. For this we use the :func:`~mongoengine.connect`

docs/upgrade.rst

@@ -52,7 +52,7 @@ rename its occurrences.
 This release includes a major rehaul of MongoEngine's code quality and
 introduces a few breaking changes. It also touches many different parts of
 the package and although all the changes have been tested and scrutinized,
-you're encouraged to thorougly test the upgrade.
+you're encouraged to thoroughly test the upgrade.
 
 First breaking change involves renaming `ConnectionError` to `MongoEngineConnectionError`.
 If you import or catch this exception, you'll need to rename it in your code.
@@ -85,10 +85,10 @@ by default from now on.
 
 The 0.8.7 package on pypi was corrupted.  If upgrading from 0.8.7 to 0.9.0 please follow: ::
 
-    pip uninstall pymongo
+    python -m pip uninstall pymongo
-    pip uninstall mongoengine
+    python -m pip uninstall mongoengine
-    pip install pymongo==2.8
+    python -m pip install pymongo==2.8
-    pip install mongoengine
+    python -m pip install mongoengine
 
 0.8.7
 *****
@@ -153,7 +153,7 @@ inherited classes like so: ::
 
     # 4. Remove indexes
     info = collection.index_information()
-    indexes_to_drop = [key for key, value in info.iteritems()
+    indexes_to_drop = [key for key, value in info.items()
                        if '_types' in dict(value['key'])]
     for index in indexes_to_drop:
         collection.drop_index(index)

mongoengine/__init__.py

@@ -18,12 +18,17 @@ from mongoengine.queryset import *
 from mongoengine.signals import *
 
 
-__all__ = (list(document.__all__) + list(fields.__all__) +
+__all__ = (
-           list(connection.__all__) + list(queryset.__all__) +
+    list(document.__all__)
-           list(signals.__all__) + list(errors.__all__))
+    + list(fields.__all__)
+    + list(connection.__all__)
+    + list(queryset.__all__)
+    + list(signals.__all__)
+    + list(errors.__all__)
+)
 
 
-VERSION = (0, 18, 1)
+VERSION = (0, 20, 0)
 
 
 def get_version():
@@ -31,7 +36,7 @@ def get_version():
 
     For example, if `VERSION == (0, 10, 7)`, return '0.10.7'.
     """
-    return '.'.join(map(str, VERSION))
+    return ".".join(map(str, VERSION))
 
 
 __version__ = get_version()

mongoengine/base/__init__.py

@@ -12,17 +12,22 @@ from mongoengine.base.metaclasses import *
 
 __all__ = (
     # common
-    'UPDATE_OPERATORS', '_document_registry', 'get_document',
+    "UPDATE_OPERATORS",
-
+    "_document_registry",
+    "get_document",
     # datastructures
-    'BaseDict', 'BaseList', 'EmbeddedDocumentList', 'LazyReference',
+    "BaseDict",
-
+    "BaseList",
+    "EmbeddedDocumentList",
+    "LazyReference",
     # document
-    'BaseDocument',
+    "BaseDocument",
-
     # fields
-    'BaseField', 'ComplexBaseField', 'ObjectIdField', 'GeoJsonBaseField',
+    "BaseField",
-
+    "ComplexBaseField",
+    "ObjectIdField",
+    "GeoJsonBaseField",
     # metaclasses
-    'DocumentMetaclass', 'TopLevelDocumentMetaclass'
+    "DocumentMetaclass",
+    "TopLevelDocumentMetaclass",
 )

mongoengine/base/common.py

@@ -1,12 +1,25 @@
 from mongoengine.errors import NotRegistered
 
-__all__ = ('UPDATE_OPERATORS', 'get_document', '_document_registry')
+__all__ = ("UPDATE_OPERATORS", "get_document", "_document_registry")
 
 
-UPDATE_OPERATORS = {'set', 'unset', 'inc', 'dec', 'mul',
+UPDATE_OPERATORS = {
-                    'pop', 'push', 'push_all', 'pull',
+    "set",
-                    'pull_all', 'add_to_set', 'set_on_insert',
+    "unset",
-                    'min', 'max', 'rename'}
+    "inc",
+    "dec",
+    "mul",
+    "pop",
+    "push",
+    "push_all",
+    "pull",
+    "pull_all",
+    "add_to_set",
+    "set_on_insert",
+    "min",
+    "max",
+    "rename",
+}
 
 
 _document_registry = {}
@@ -17,25 +30,33 @@ def get_document(name):
     doc = _document_registry.get(name, None)
     if not doc:
         # Possible old style name
-        single_end = name.split('.')[-1]
+        single_end = name.split(".")[-1]
-        compound_end = '.%s' % single_end
+        compound_end = ".%s" % single_end
-        possible_match = [k for k in _document_registry
+        possible_match = [
-                          if k.endswith(compound_end) or k == single_end]
+            k for k in _document_registry if k.endswith(compound_end) or k == single_end
+        ]
         if len(possible_match) == 1:
             doc = _document_registry.get(possible_match.pop(), None)
     if not doc:
-        raise NotRegistered("""
+        raise NotRegistered(
+            """
             `%s` has not been registered in the document registry.
             Importing the document class automatically registers it, has it
             been imported?
-        """.strip() % name)
+        """.strip()
+            % name
+        )
     return doc
 
 
 def _get_documents_by_db(connection_alias, default_connection_alias):
     """Get all registered Documents class attached to a given database"""
-    def get_doc_alias(doc_cls):
-        return doc_cls._meta.get('db_alias', default_connection_alias)
 
-    return [doc_cls for doc_cls in _document_registry.values()
+    def get_doc_alias(doc_cls):
-            if get_doc_alias(doc_cls) == connection_alias]
+        return doc_cls._meta.get("db_alias", default_connection_alias)
+
+    return [
+        doc_cls
+        for doc_cls in _document_registry.values()
+        if get_doc_alias(doc_cls) == connection_alias
+    ]

mongoengine/base/datastructures.py

@@ -1,30 +1,40 @@
 import weakref
 
 from bson import DBRef
-import six
-from six import iteritems
 
 from mongoengine.common import _import_class
 from mongoengine.errors import DoesNotExist, MultipleObjectsReturned
 
-__all__ = ('BaseDict', 'StrictDict', 'BaseList', 'EmbeddedDocumentList', 'LazyReference')
+__all__ = (
+    "BaseDict",
+    "StrictDict",
+    "BaseList",
+    "EmbeddedDocumentList",
+    "LazyReference",
+)
 
 
 def mark_as_changed_wrapper(parent_method):
-    """Decorators that ensures _mark_as_changed method gets called"""
+    """Decorator that ensures _mark_as_changed method gets called."""
+
     def wrapper(self, *args, **kwargs):
-        result = parent_method(self, *args, **kwargs)   # Can't use super() in the decorator
+        # Can't use super() in the decorator.
+        result = parent_method(self, *args, **kwargs)
         self._mark_as_changed()
         return result
+
     return wrapper
 
 
 def mark_key_as_changed_wrapper(parent_method):
-    """Decorators that ensures _mark_as_changed method gets called with the key argument"""
+    """Decorator that ensures _mark_as_changed method gets called with the key argument"""
+
     def wrapper(self, key, *args, **kwargs):
-        result = parent_method(self, key, *args, **kwargs)   # Can't use super() in the decorator
+        # Can't use super() in the decorator.
+        result = parent_method(self, key, *args, **kwargs)
         self._mark_as_changed(key)
         return result
+
     return wrapper
 
 
@@ -36,12 +46,12 @@ class BaseDict(dict):
     _name = None
 
     def __init__(self, dict_items, instance, name):
-        BaseDocument = _import_class('BaseDocument')
+        BaseDocument = _import_class("BaseDocument")
 
         if isinstance(instance, BaseDocument):
             self._instance = weakref.proxy(instance)
         self._name = name
-        super(BaseDict, self).__init__(dict_items)
+        super().__init__(dict_items)
 
     def get(self, key, default=None):
         # get does not use __getitem__ by default so we must override it as well
@@ -51,18 +61,18 @@ class BaseDict(dict):
             return default
 
     def __getitem__(self, key):
-        value = super(BaseDict, self).__getitem__(key)
+        value = super().__getitem__(key)
 
-        EmbeddedDocument = _import_class('EmbeddedDocument')
+        EmbeddedDocument = _import_class("EmbeddedDocument")
         if isinstance(value, EmbeddedDocument) and value._instance is None:
             value._instance = self._instance
         elif isinstance(value, dict) and not isinstance(value, BaseDict):
-            value = BaseDict(value, None, '%s.%s' % (self._name, key))
+            value = BaseDict(value, None, "{}.{}".format(self._name, key))
-            super(BaseDict, self).__setitem__(key, value)
+            super().__setitem__(key, value)
             value._instance = self._instance
         elif isinstance(value, list) and not isinstance(value, BaseList):
-            value = BaseList(value, None, '%s.%s' % (self._name, key))
+            value = BaseList(value, None, "{}.{}".format(self._name, key))
-            super(BaseDict, self).__setitem__(key, value)
+            super().__setitem__(key, value)
             value._instance = self._instance
         return value
 
@@ -85,9 +95,9 @@ class BaseDict(dict):
     setdefault = mark_as_changed_wrapper(dict.setdefault)
 
     def _mark_as_changed(self, key=None):
-        if hasattr(self._instance, '_mark_as_changed'):
+        if hasattr(self._instance, "_mark_as_changed"):
             if key:
-                self._instance._mark_as_changed('%s.%s' % (self._name, key))
+                self._instance._mark_as_changed("{}.{}".format(self._name, key))
             else:
                 self._instance._mark_as_changed(self._name)
 
@@ -100,39 +110,41 @@ class BaseList(list):
     _name = None
 
     def __init__(self, list_items, instance, name):
-        BaseDocument = _import_class('BaseDocument')
+        BaseDocument = _import_class("BaseDocument")
 
         if isinstance(instance, BaseDocument):
             self._instance = weakref.proxy(instance)
         self._name = name
-        super(BaseList, self).__init__(list_items)
+        super().__init__(list_items)
 
     def __getitem__(self, key):
-        value = super(BaseList, self).__getitem__(key)
+        # change index to positive value because MongoDB does not support negative one
+        if isinstance(key, int) and key < 0:
+            key = len(self) + key
+        value = super().__getitem__(key)
 
         if isinstance(key, slice):
             # When receiving a slice operator, we don't convert the structure and bind
             # to parent's instance. This is buggy for now but would require more work to be handled properly
             return value
 
-        EmbeddedDocument = _import_class('EmbeddedDocument')
+        EmbeddedDocument = _import_class("EmbeddedDocument")
         if isinstance(value, EmbeddedDocument) and value._instance is None:
             value._instance = self._instance
         elif isinstance(value, dict) and not isinstance(value, BaseDict):
             # Replace dict by BaseDict
-            value = BaseDict(value, None, '%s.%s' % (self._name, key))
+            value = BaseDict(value, None, "{}.{}".format(self._name, key))
-            super(BaseList, self).__setitem__(key, value)
+            super().__setitem__(key, value)
             value._instance = self._instance
         elif isinstance(value, list) and not isinstance(value, BaseList):
             # Replace list by BaseList
-            value = BaseList(value, None, '%s.%s' % (self._name, key))
+            value = BaseList(value, None, "{}.{}".format(self._name, key))
-            super(BaseList, self).__setitem__(key, value)
+            super().__setitem__(key, value)
             value._instance = self._instance
         return value
 
     def __iter__(self):
-        for v in super(BaseList, self).__iter__():
+        yield from super().__iter__()
-            yield v
 
     def __getstate__(self):
         self.instance = None
@@ -150,7 +162,7 @@ class BaseList(list):
             # instead, we simply marks the whole list as changed
             changed_key = None
 
-        result = super(BaseList, self).__setitem__(key, value)
+        result = super().__setitem__(key, value)
         self._mark_as_changed(changed_key)
         return result
 
@@ -165,33 +177,19 @@ class BaseList(list):
     __iadd__ = mark_as_changed_wrapper(list.__iadd__)
     __imul__ = mark_as_changed_wrapper(list.__imul__)
 
-    if six.PY2:
-        # Under py3 __setslice__, __delslice__ and __getslice__
-        # are replaced by __setitem__, __delitem__ and __getitem__ with a slice as parameter
-        # so we mimic this under python 2
-        def __setslice__(self, i, j, sequence):
-            return self.__setitem__(slice(i, j), sequence)
-
-        def __delslice__(self, i, j):
-            return self.__delitem__(slice(i, j))
-
-        def __getslice__(self, i, j):
-            return self.__getitem__(slice(i, j))
-
     def _mark_as_changed(self, key=None):
-        if hasattr(self._instance, '_mark_as_changed'):
+        if hasattr(self._instance, "_mark_as_changed"):
-            if key:
+            if key is not None:
                 self._instance._mark_as_changed(
-                    '%s.%s' % (self._name, key % len(self))
+                    "{}.{}".format(self._name, key % len(self))
                 )
             else:
                 self._instance._mark_as_changed(self._name)
 
 
 class EmbeddedDocumentList(BaseList):
-
     def __init__(self, list_items, instance, name):
-        super(EmbeddedDocumentList, self).__init__(list_items, instance, name)
+        super().__init__(list_items, instance, name)
         self._instance = instance
 
     @classmethod
@@ -201,7 +199,7 @@ class EmbeddedDocumentList(BaseList):
         """
         for key, expected_value in kwargs.items():
             doc_val = getattr(embedded_doc, key)
-            if doc_val != expected_value and six.text_type(doc_val) != expected_value:
+            if doc_val != expected_value and str(doc_val) != expected_value:
                 return False
         return True
 
@@ -274,12 +272,10 @@ class EmbeddedDocumentList(BaseList):
         """
         values = self.__only_matches(self, kwargs)
         if len(values) == 0:
-            raise DoesNotExist(
+            raise DoesNotExist("%s matching query does not exist." % self._name)
-                '%s matching query does not exist.' % self._name
-            )
         elif len(values) > 1:
             raise MultipleObjectsReturned(
-                '%d items returned, instead of 1' % len(values)
+                "%d items returned, instead of 1" % len(values)
             )
 
         return values[0]
@@ -293,11 +289,11 @@ class EmbeddedDocumentList(BaseList):
 
     def create(self, **values):
         """
-        Creates a new embedded document and saves it to the database.
+        Creates a new instance of the EmbeddedDocument and appends it to this EmbeddedDocumentList.
 
         .. note::
-            The embedded document changes are not automatically saved
+            the instance of the EmbeddedDocument is not automatically saved to the database.
-            to the database after calling this method.
+            You still need to call .save() on the parent Document.
 
         :param values: A dictionary of values for the embedded document.
         :return: The new embedded document instance.
@@ -358,24 +354,24 @@ class EmbeddedDocumentList(BaseList):
         return len(values)
 
 
-class StrictDict(object):
+class StrictDict:
     __slots__ = ()
-    _special_fields = {'get', 'pop', 'iteritems', 'items', 'keys', 'create'}
+    _special_fields = {"get", "pop", "iteritems", "items", "keys", "create"}
     _classes = {}
 
     def __init__(self, **kwargs):
-        for k, v in iteritems(kwargs):
+        for k, v in kwargs.items():
             setattr(self, k, v)
 
     def __getitem__(self, key):
-        key = '_reserved_' + key if key in self._special_fields else key
+        key = "_reserved_" + key if key in self._special_fields else key
         try:
             return getattr(self, key)
         except AttributeError:
             raise KeyError(key)
 
     def __setitem__(self, key, value):
-        key = '_reserved_' + key if key in self._special_fields else key
+        key = "_reserved_" + key if key in self._special_fields else key
         return setattr(self, key, value)
 
     def __contains__(self, key):
@@ -412,37 +408,42 @@ class StrictDict(object):
         return (key for key in self.__slots__ if hasattr(self, key))
 
     def __len__(self):
-        return len(list(iteritems(self)))
+        return len(list(self.items()))
 
     def __eq__(self, other):
-        return self.items() == other.items()
+        return list(self.items()) == list(other.items())
 
     def __ne__(self, other):
-        return self.items() != other.items()
+        return not (self == other)
 
     @classmethod
     def create(cls, allowed_keys):
-        allowed_keys_tuple = tuple(('_reserved_' + k if k in cls._special_fields else k) for k in allowed_keys)
+        allowed_keys_tuple = tuple(
+            ("_reserved_" + k if k in cls._special_fields else k) for k in allowed_keys
+        )
         allowed_keys = frozenset(allowed_keys_tuple)
         if allowed_keys not in cls._classes:
+
             class SpecificStrictDict(cls):
                 __slots__ = allowed_keys_tuple
 
                 def __repr__(self):
-                    return '{%s}' % ', '.join('"{0!s}": {1!r}'.format(k, v) for k, v in self.items())
+                    return "{%s}" % ", ".join(
+                        '"{!s}": {!r}'.format(k, v) for k, v in self.items()
+                    )
 
             cls._classes[allowed_keys] = SpecificStrictDict
         return cls._classes[allowed_keys]
 
 
 class LazyReference(DBRef):
-    __slots__ = ('_cached_doc', 'passthrough', 'document_type')
+    __slots__ = ("_cached_doc", "passthrough", "document_type")
 
     def fetch(self, force=False):
         if not self._cached_doc or force:
             self._cached_doc = self.document_type.objects.get(pk=self.pk)
             if not self._cached_doc:
-                raise DoesNotExist('Trying to dereference unknown document %s' % (self))
+                raise DoesNotExist("Trying to dereference unknown document %s" % (self))
         return self._cached_doc
 
     @property
@@ -453,7 +454,7 @@ class LazyReference(DBRef):
         self.document_type = document_type
         self._cached_doc = cached_doc
         self.passthrough = passthrough
-        super(LazyReference, self).__init__(self.document_type._get_collection_name(), pk)
+        super().__init__(self.document_type._get_collection_name(), pk)
 
     def __getitem__(self, name):
         if not self.passthrough:
@@ -462,7 +463,7 @@ class LazyReference(DBRef):
         return document[name]
 
     def __getattr__(self, name):
-        if not object.__getattribute__(self, 'passthrough'):
+        if not object.__getattribute__(self, "passthrough"):
             raise AttributeError()
         document = self.fetch()
         try:
@@ -471,4 +472,4 @@ class LazyReference(DBRef):
             raise AttributeError()
 
     def __repr__(self):
-        return "<LazyReference(%s, %r)>" % (self.document_type, self.pk)
+        return "<LazyReference({}, {!r})>".format(self.document_type, self.pk)

mongoengine/base/fields.py

@@ -4,25 +4,22 @@ import weakref
 
 from bson import DBRef, ObjectId, SON
 import pymongo
-import six
-from six import iteritems
 
 from mongoengine.base.common import UPDATE_OPERATORS
-from mongoengine.base.datastructures import (BaseDict, BaseList,
+from mongoengine.base.datastructures import BaseDict, BaseList, EmbeddedDocumentList
-                                             EmbeddedDocumentList)
 from mongoengine.common import _import_class
 from mongoengine.errors import DeprecatedError, ValidationError
 
-__all__ = ('BaseField', 'ComplexBaseField', 'ObjectIdField',
+__all__ = ("BaseField", "ComplexBaseField", "ObjectIdField", "GeoJsonBaseField")
-           'GeoJsonBaseField')
 
 
-class BaseField(object):
+class BaseField:
     """A base class for fields in a MongoDB document. Instances of this class
     may be added to subclasses of `Document` to define a document's schema.
 
     .. versionchanged:: 0.5 - added verbose and help text
     """
+
     name = None
     _geo_index = False
     _auto_gen = False  # Call `generate` to generate a value
@@ -34,14 +31,23 @@ class BaseField(object):
     creation_counter = 0
     auto_creation_counter = -1
 
-    def __init__(self, db_field=None, name=None, required=False, default=None,
+    def __init__(
-                 unique=False, unique_with=None, primary_key=False,
+        self,
-                 validation=None, choices=None, null=False, sparse=False,
+        db_field=None,
-                 **kwargs):
+        required=False,
+        default=None,
+        unique=False,
+        unique_with=None,
+        primary_key=False,
+        validation=None,
+        choices=None,
+        null=False,
+        sparse=False,
+        **kwargs
+    ):
         """
         :param db_field: The database field to store this field in
             (defaults to the name of the field)
-        :param name: Deprecated - use db_field
         :param required: If the field is required. Whether it has to have a
             value or not. Defaults to False.
         :param default: (optional) The default value for this field if no value
@@ -65,11 +71,8 @@ class BaseField(object):
             existing attributes. Common metadata includes `verbose_name` and
             `help_text`.
         """
-        self.db_field = (db_field or name) if not primary_key else '_id'
+        self.db_field = db_field if not primary_key else "_id"
 
-        if name:
-            msg = 'Field\'s "name" attribute deprecated in favour of "db_field"'
-            warnings.warn(msg, DeprecationWarning)
         self.required = required or primary_key
         self.default = default
         self.unique = bool(unique or unique_with)
@@ -82,17 +85,14 @@ class BaseField(object):
         self._owner_document = None
 
         # Make sure db_field is a string (if it's explicitly defined).
-        if (
+        if self.db_field is not None and not isinstance(self.db_field, str):
-            self.db_field is not None and
+            raise TypeError("db_field should be a string.")
-            not isinstance(self.db_field, six.string_types)
-        ):
-            raise TypeError('db_field should be a string.')
 
         # Make sure db_field doesn't contain any forbidden characters.
-        if isinstance(self.db_field, six.string_types) and (
+        if isinstance(self.db_field, str) and (
-            '.' in self.db_field or
+            "." in self.db_field
-            '\0' in self.db_field or
+            or "\0" in self.db_field
-            self.db_field.startswith('$')
+            or self.db_field.startswith("$")
         ):
             raise ValueError(
                 'field names cannot contain dots (".") or null characters '
@@ -102,15 +102,17 @@ class BaseField(object):
         # Detect and report conflicts between metadata and base properties.
         conflicts = set(dir(self)) & set(kwargs)
         if conflicts:
-            raise TypeError('%s already has attribute(s): %s' % (
+            raise TypeError(
-                self.__class__.__name__, ', '.join(conflicts)))
+                "%s already has attribute(s): %s"
+                % (self.__class__.__name__, ", ".join(conflicts))
+            )
 
         # Assign metadata to the instance
         # This efficient method is available because no __slots__ are defined.
         self.__dict__.update(kwargs)
 
         # Adjust the appropriate creation counter, and save our local copy.
-        if self.db_field == '_id':
+        if self.db_field == "_id":
             self.creation_counter = BaseField.auto_creation_counter
             BaseField.auto_creation_counter -= 1
         else:
@@ -128,10 +130,9 @@ class BaseField(object):
         return instance._data.get(self.name)
 
     def __set__(self, instance, value):
-        """Descriptor for assigning a value to a field in a document.
+        """Descriptor for assigning a value to a field in a document."""
-        """
+        # If setting to None and there is a default value provided for this
-        # If setting to None and there is a default
+        # field, then set the value to the default value.
-        # Then set the value to the default value
         if value is None:
             if self.null:
                 value = None
@@ -142,24 +143,29 @@ class BaseField(object):
 
         if instance._initialised:
             try:
-                if (self.name not in instance._data or
+                value_has_changed = (
-                        instance._data[self.name] != value):
+                    self.name not in instance._data
+                    or instance._data[self.name] != value
+                )
+                if value_has_changed:
                     instance._mark_as_changed(self.name)
             except Exception:
-                # Values cant be compared eg: naive and tz datetimes
+                # Some values can't be compared and throw an error when we
-                # So mark it as changed
+                # attempt to do so (e.g. tz-naive and tz-aware datetimes).
+                # Mark the field as changed in such cases.
                 instance._mark_as_changed(self.name)
 
-        EmbeddedDocument = _import_class('EmbeddedDocument')
+        EmbeddedDocument = _import_class("EmbeddedDocument")
         if isinstance(value, EmbeddedDocument):
             value._instance = weakref.proxy(instance)
         elif isinstance(value, (list, tuple)):
             for v in value:
                 if isinstance(v, EmbeddedDocument):
                     v._instance = weakref.proxy(instance)
+
         instance._data[self.name] = value
 
-    def error(self, message='', errors=None, field_name=None):
+    def error(self, message="", errors=None, field_name=None):
         """Raise a ValidationError."""
         field_name = field_name if field_name else self.name
         raise ValidationError(message, errors=errors, field_name=field_name)
@@ -176,11 +182,11 @@ class BaseField(object):
         """Helper method to call to_mongo with proper inputs."""
         f_inputs = self.to_mongo.__code__.co_varnames
         ex_vars = {}
-        if 'fields' in f_inputs:
+        if "fields" in f_inputs:
-            ex_vars['fields'] = fields
+            ex_vars["fields"] = fields
 
-        if 'use_db_field' in f_inputs:
+        if "use_db_field" in f_inputs:
-            ex_vars['use_db_field'] = use_db_field
+            ex_vars["use_db_field"] = use_db_field
 
         return self.to_mongo(value, **ex_vars)
 
@@ -195,8 +201,8 @@ class BaseField(object):
         pass
 
     def _validate_choices(self, value):
-        Document = _import_class('Document')
+        Document = _import_class("Document")
-        EmbeddedDocument = _import_class('EmbeddedDocument')
+        EmbeddedDocument = _import_class("EmbeddedDocument")
 
         choice_list = self.choices
         if isinstance(next(iter(choice_list)), (list, tuple)):
@@ -206,16 +212,12 @@ class BaseField(object):
         # Choices which are other types of Documents
         if isinstance(value, (Document, EmbeddedDocument)):
             if not any(isinstance(value, c) for c in choice_list):
-                self.error(
+                self.error("Value must be an instance of %s" % (choice_list))
-                    'Value must be an instance of %s' % (
-                        six.text_type(choice_list)
-                    )
-                )
         # Choices which are types other than Documents
         else:
             values = value if isinstance(value, (list, tuple)) else [value]
             if len(set(values) - set(choice_list)):
-                self.error('Value must be one of %s' % six.text_type(choice_list))
+                self.error("Value must be one of %s" % str(choice_list))
 
     def _validate(self, value, **kwargs):
         # Check the Choices Constraint
@@ -231,13 +233,17 @@ class BaseField(object):
                     # in favor of having validation raising a ValidationError
                     ret = self.validation(value)
                     if ret is not None:
-                        raise DeprecatedError('validation argument for `%s` must not return anything, '
+                        raise DeprecatedError(
-                                              'it should raise a ValidationError if validation fails' % self.name)
+                            "validation argument for `%s` must not return anything, "
+                            "it should raise a ValidationError if validation fails"
+                            % self.name
+                        )
                 except ValidationError as ex:
                     self.error(str(ex))
             else:
-                raise ValueError('validation argument for `"%s"` must be a '
+                raise ValueError(
-                                 'callable.' % self.name)
+                    'validation argument for `"%s"` must be a ' "callable." % self.name
+                )
 
         self.validate(value, **kwargs)
 
@@ -271,35 +277,41 @@ class ComplexBaseField(BaseField):
             # Document class being used rather than a document object
             return self
 
-        ReferenceField = _import_class('ReferenceField')
+        ReferenceField = _import_class("ReferenceField")
-        GenericReferenceField = _import_class('GenericReferenceField')
+        GenericReferenceField = _import_class("GenericReferenceField")
-        EmbeddedDocumentListField = _import_class('EmbeddedDocumentListField')
+        EmbeddedDocumentListField = _import_class("EmbeddedDocumentListField")
 
         auto_dereference = instance._fields[self.name]._auto_dereference
 
-        dereference = (auto_dereference and
+        dereference = auto_dereference and (
-                       (self.field is None or isinstance(self.field,
+            self.field is None
-                                                         (GenericReferenceField, ReferenceField))))
+            or isinstance(self.field, (GenericReferenceField, ReferenceField))
+        )
 
-        _dereference = _import_class('DeReference')()
+        _dereference = _import_class("DeReference")()
 
-        if (instance._initialised and
+        if (
-                dereference and
+            instance._initialised
-                instance._data.get(self.name) and
+            and dereference
-                not getattr(instance._data[self.name], '_dereferenced', False)):
+            and instance._data.get(self.name)
+            and not getattr(instance._data[self.name], "_dereferenced", False)
+        ):
             instance._data[self.name] = _dereference(
-                instance._data.get(self.name), max_depth=1, instance=instance,
+                instance._data.get(self.name),
-                name=self.name
+                max_depth=1,
+                instance=instance,
+                name=self.name,
             )
-            if hasattr(instance._data[self.name], '_dereferenced'):
+            if hasattr(instance._data[self.name], "_dereferenced"):
                 instance._data[self.name]._dereferenced = True
 
-        value = super(ComplexBaseField, self).__get__(instance, owner)
+        value = super().__get__(instance, owner)
 
         # Convert lists / values so we can watch for any changes on them
         if isinstance(value, (list, tuple)):
-            if (issubclass(type(self), EmbeddedDocumentListField) and
+            if issubclass(type(self), EmbeddedDocumentListField) and not isinstance(
-                    not isinstance(value, EmbeddedDocumentList)):
+                value, EmbeddedDocumentList
+            ):
                 value = EmbeddedDocumentList(value, instance, self.name)
             elif not isinstance(value, BaseList):
                 value = BaseList(value, instance, self.name)
@@ -308,12 +320,13 @@ class ComplexBaseField(BaseField):
             value = BaseDict(value, instance, self.name)
             instance._data[self.name] = value
 
-        if (auto_dereference and instance._initialised and
+        if (
-                isinstance(value, (BaseList, BaseDict)) and
+            auto_dereference
-                not value._dereferenced):
+            and instance._initialised
-            value = _dereference(
+            and isinstance(value, (BaseList, BaseDict))
-                value, max_depth=1, instance=instance, name=self.name
+            and not value._dereferenced
-            )
+        ):
+            value = _dereference(value, max_depth=1, instance=instance, name=self.name)
             value._dereferenced = True
             instance._data[self.name] = value
 
@@ -321,19 +334,19 @@ class ComplexBaseField(BaseField):
 
     def to_python(self, value):
         """Convert a MongoDB-compatible type to a Python type."""
-        if isinstance(value, six.string_types):
+        if isinstance(value, str):
             return value
 
-        if hasattr(value, 'to_python'):
+        if hasattr(value, "to_python"):
             return value.to_python()
 
-        BaseDocument = _import_class('BaseDocument')
+        BaseDocument = _import_class("BaseDocument")
         if isinstance(value, BaseDocument):
             # Something is wrong, return the value as it is
             return value
 
         is_list = False
-        if not hasattr(value, 'items'):
+        if not hasattr(value, "items"):
             try:
                 is_list = True
                 value = {idx: v for idx, v in enumerate(value)}
@@ -342,50 +355,54 @@ class ComplexBaseField(BaseField):
 
         if self.field:
             self.field._auto_dereference = self._auto_dereference
-            value_dict = {key: self.field.to_python(item)
+            value_dict = {
-                          for key, item in value.items()}
+                key: self.field.to_python(item) for key, item in value.items()
+            }
         else:
-            Document = _import_class('Document')
+            Document = _import_class("Document")
             value_dict = {}
             for k, v in value.items():
                 if isinstance(v, Document):
                     # We need the id from the saved object to create the DBRef
                     if v.pk is None:
-                        self.error('You can only reference documents once they'
+                        self.error(
-                                   ' have been saved to the database')
+                            "You can only reference documents once they"
+                            " have been saved to the database"
+                        )
                     collection = v._get_collection_name()
                     value_dict[k] = DBRef(collection, v.pk)
-                elif hasattr(v, 'to_python'):
+                elif hasattr(v, "to_python"):
                     value_dict[k] = v.to_python()
                 else:
                     value_dict[k] = self.to_python(v)
 
         if is_list:  # Convert back to a list
-            return [v for _, v in sorted(value_dict.items(),
+            return [
-                                         key=operator.itemgetter(0))]
+                v for _, v in sorted(value_dict.items(), key=operator.itemgetter(0))
+            ]
         return value_dict
 
     def to_mongo(self, value, use_db_field=True, fields=None):
         """Convert a Python type to a MongoDB-compatible type."""
-        Document = _import_class('Document')
+        Document = _import_class("Document")
-        EmbeddedDocument = _import_class('EmbeddedDocument')
+        EmbeddedDocument = _import_class("EmbeddedDocument")
-        GenericReferenceField = _import_class('GenericReferenceField')
+        GenericReferenceField = _import_class("GenericReferenceField")
 
-        if isinstance(value, six.string_types):
+        if isinstance(value, str):
             return value
 
-        if hasattr(value, 'to_mongo'):
+        if hasattr(value, "to_mongo"):
             if isinstance(value, Document):
                 return GenericReferenceField().to_mongo(value)
             cls = value.__class__
             val = value.to_mongo(use_db_field, fields)
             # If it's a document that is not inherited add _cls
             if isinstance(value, EmbeddedDocument):
-                val['_cls'] = cls.__name__
+                val["_cls"] = cls.__name__
             return val
 
         is_list = False
-        if not hasattr(value, 'items'):
+        if not hasattr(value, "items"):
             try:
                 is_list = True
                 value = {k: v for k, v in enumerate(value)}
@@ -395,48 +412,51 @@ class ComplexBaseField(BaseField):
         if self.field:
             value_dict = {
                 key: self.field._to_mongo_safe_call(item, use_db_field, fields)
-                for key, item in iteritems(value)
+                for key, item in value.items()
             }
         else:
             value_dict = {}
-            for k, v in iteritems(value):
+            for k, v in value.items():
                 if isinstance(v, Document):
                     # We need the id from the saved object to create the DBRef
                     if v.pk is None:
-                        self.error('You can only reference documents once they'
+                        self.error(
-                                   ' have been saved to the database')
+                            "You can only reference documents once they"
+                            " have been saved to the database"
+                        )
 
                     # If its a document that is not inheritable it won't have
                     # any _cls data so make it a generic reference allows
                     # us to dereference
-                    meta = getattr(v, '_meta', {})
+                    meta = getattr(v, "_meta", {})
-                    allow_inheritance = meta.get('allow_inheritance')
+                    allow_inheritance = meta.get("allow_inheritance")
                     if not allow_inheritance and not self.field:
                         value_dict[k] = GenericReferenceField().to_mongo(v)
                     else:
                         collection = v._get_collection_name()
                         value_dict[k] = DBRef(collection, v.pk)
-                elif hasattr(v, 'to_mongo'):
+                elif hasattr(v, "to_mongo"):
                     cls = v.__class__
                     val = v.to_mongo(use_db_field, fields)
                     # If it's a document that is not inherited add _cls
                     if isinstance(v, (Document, EmbeddedDocument)):
-                        val['_cls'] = cls.__name__
+                        val["_cls"] = cls.__name__
                     value_dict[k] = val
                 else:
                     value_dict[k] = self.to_mongo(v, use_db_field, fields)
 
         if is_list:  # Convert back to a list
-            return [v for _, v in sorted(value_dict.items(),
+            return [
-                                         key=operator.itemgetter(0))]
+                v for _, v in sorted(value_dict.items(), key=operator.itemgetter(0))
+            ]
         return value_dict
 
     def validate(self, value):
         """If field is provided ensure the value is valid."""
         errors = {}
         if self.field:
-            if hasattr(value, 'iteritems') or hasattr(value, 'items'):
+            if hasattr(value, "items"):
-                sequence = iteritems(value)
+                sequence = value.items()
             else:
                 sequence = enumerate(value)
             for k, v in sequence:
@@ -449,11 +469,12 @@ class ComplexBaseField(BaseField):
 
             if errors:
                 field_class = self.field.__class__.__name__
-                self.error('Invalid %s item (%s)' % (field_class, value),
+                self.error(
-                           errors=errors)
+                    "Invalid {} item ({})".format(field_class, value), errors=errors
+                )
         # Don't allow empty values if required
         if self.required and not value:
-            self.error('Field is required and cannot be empty')
+            self.error("Field is required and cannot be empty")
 
     def prepare_query_value(self, op, value):
         return self.to_mongo(value)
@@ -483,10 +504,9 @@ class ObjectIdField(BaseField):
     def to_mongo(self, value):
         if not isinstance(value, ObjectId):
             try:
-                return ObjectId(six.text_type(value))
+                return ObjectId(str(value))
             except Exception as e:
-                # e.message attribute has been deprecated since Python 2.6
+                self.error(str(e))
-                self.error(six.text_type(e))
         return value
 
     def prepare_query_value(self, op, value):
@@ -494,9 +514,9 @@ class ObjectIdField(BaseField):
 
     def validate(self, value):
         try:
-            ObjectId(six.text_type(value))
+            ObjectId(str(value))
         except Exception:
-            self.error('Invalid Object ID')
+            self.error("Invalid ObjectID")
 
 
 class GeoJsonBaseField(BaseField):
@@ -506,72 +526,73 @@ class GeoJsonBaseField(BaseField):
     """
 
     _geo_index = pymongo.GEOSPHERE
-    _type = 'GeoBase'
+    _type = "GeoBase"
 
     def __init__(self, auto_index=True, *args, **kwargs):
         """
         :param bool auto_index: Automatically create a '2dsphere' index.\
             Defaults to `True`.
         """
-        self._name = '%sField' % self._type
+        self._name = "%sField" % self._type
         if not auto_index:
             self._geo_index = False
-        super(GeoJsonBaseField, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
 
     def validate(self, value):
         """Validate the GeoJson object based on its type."""
         if isinstance(value, dict):
-            if set(value.keys()) == {'type', 'coordinates'}:
+            if set(value.keys()) == {"type", "coordinates"}:
-                if value['type'] != self._type:
+                if value["type"] != self._type:
-                    self.error('%s type must be "%s"' %
+                    self.error('{} type must be "{}"'.format(self._name, self._type))
-                               (self._name, self._type))
+                return self.validate(value["coordinates"])
-                return self.validate(value['coordinates'])
             else:
-                self.error('%s can only accept a valid GeoJson dictionary'
+                self.error(
-                           ' or lists of (x, y)' % self._name)
+                    "%s can only accept a valid GeoJson dictionary"
+                    " or lists of (x, y)" % self._name
+                )
                 return
         elif not isinstance(value, (list, tuple)):
-            self.error('%s can only accept lists of [x, y]' % self._name)
+            self.error("%s can only accept lists of [x, y]" % self._name)
             return
 
-        validate = getattr(self, '_validate_%s' % self._type.lower())
+        validate = getattr(self, "_validate_%s" % self._type.lower())
         error = validate(value)
         if error:
             self.error(error)
 
     def _validate_polygon(self, value, top_level=True):
         if not isinstance(value, (list, tuple)):
-            return 'Polygons must contain list of linestrings'
+            return "Polygons must contain list of linestrings"
 
         # Quick and dirty validator
         try:
             value[0][0][0]
         except (TypeError, IndexError):
-            return 'Invalid Polygon must contain at least one valid linestring'
+            return "Invalid Polygon must contain at least one valid linestring"
 
         errors = []
         for val in value:
             error = self._validate_linestring(val, False)
             if not error and val[0] != val[-1]:
-                error = 'LineStrings must start and end at the same point'
+                error = "LineStrings must start and end at the same point"
             if error and error not in errors:
                 errors.append(error)
         if errors:
             if top_level:
-                return 'Invalid Polygon:\n%s' % ', '.join(errors)
+                return "Invalid Polygon:\n%s" % ", ".join(errors)
             else:
-                return '%s' % ', '.join(errors)
+                return "%s" % ", ".join(errors)
 
     def _validate_linestring(self, value, top_level=True):
         """Validate a linestring."""
         if not isinstance(value, (list, tuple)):
-            return 'LineStrings must contain list of coordinate pairs'
+            return "LineStrings must contain list of coordinate pairs"
 
         # Quick and dirty validator
         try:
             value[0][0]
         except (TypeError, IndexError):
-            return 'Invalid LineString must contain at least one valid point'
+            return "Invalid LineString must contain at least one valid point"
 
         errors = []
         for val in value:
@@ -580,29 +601,30 @@ class GeoJsonBaseField(BaseField):
                 errors.append(error)
         if errors:
             if top_level:
-                return 'Invalid LineString:\n%s' % ', '.join(errors)
+                return "Invalid LineString:\n%s" % ", ".join(errors)
             else:
-                return '%s' % ', '.join(errors)
+                return "%s" % ", ".join(errors)
 
     def _validate_point(self, value):
         """Validate each set of coords"""
         if not isinstance(value, (list, tuple)):
-            return 'Points must be a list of coordinate pairs'
+            return "Points must be a list of coordinate pairs"
         elif not len(value) == 2:
-            return 'Value (%s) must be a two-dimensional point' % repr(value)
+            return "Value (%s) must be a two-dimensional point" % repr(value)
-        elif (not isinstance(value[0], (float, int)) or
+        elif not isinstance(value[0], (float, int)) or not isinstance(
-              not isinstance(value[1], (float, int))):
+            value[1], (float, int)
-            return 'Both values (%s) in point must be float or int' % repr(value)
+        ):
+            return "Both values (%s) in point must be float or int" % repr(value)
 
     def _validate_multipoint(self, value):
         if not isinstance(value, (list, tuple)):
-            return 'MultiPoint must be a list of Point'
+            return "MultiPoint must be a list of Point"
 
         # Quick and dirty validator
         try:
             value[0][0]
         except (TypeError, IndexError):
-            return 'Invalid MultiPoint must contain at least one valid point'
+            return "Invalid MultiPoint must contain at least one valid point"
 
         errors = []
         for point in value:
@@ -611,17 +633,17 @@ class GeoJsonBaseField(BaseField):
                 errors.append(error)
 
         if errors:
-            return '%s' % ', '.join(errors)
+            return "%s" % ", ".join(errors)
 
     def _validate_multilinestring(self, value, top_level=True):
         if not isinstance(value, (list, tuple)):
-            return 'MultiLineString must be a list of LineString'
+            return "MultiLineString must be a list of LineString"
 
         # Quick and dirty validator
         try:
             value[0][0][0]
         except (TypeError, IndexError):
-            return 'Invalid MultiLineString must contain at least one valid linestring'
+            return "Invalid MultiLineString must contain at least one valid linestring"
 
         errors = []
         for linestring in value:
@@ -631,19 +653,19 @@ class GeoJsonBaseField(BaseField):
 
         if errors:
             if top_level:
-                return 'Invalid MultiLineString:\n%s' % ', '.join(errors)
+                return "Invalid MultiLineString:\n%s" % ", ".join(errors)
             else:
-                return '%s' % ', '.join(errors)
+                return "%s" % ", ".join(errors)
 
     def _validate_multipolygon(self, value):
         if not isinstance(value, (list, tuple)):
-            return 'MultiPolygon must be a list of Polygon'
+            return "MultiPolygon must be a list of Polygon"
 
         # Quick and dirty validator
         try:
             value[0][0][0][0]
         except (TypeError, IndexError):
-            return 'Invalid MultiPolygon must contain at least one valid Polygon'
+            return "Invalid MultiPolygon must contain at least one valid Polygon"
 
         errors = []
         for polygon in value:
@@ -652,9 +674,9 @@ class GeoJsonBaseField(BaseField):
                 errors.append(error)
 
         if errors:
-            return 'Invalid MultiPolygon:\n%s' % ', '.join(errors)
+            return "Invalid MultiPolygon:\n%s" % ", ".join(errors)
 
     def to_mongo(self, value):
         if isinstance(value, dict):
             return value
-        return SON([('type', self._type), ('coordinates', value)])
+        return SON([("type", self._type), ("coordinates", value)])

mongoengine/base/metaclasses.py

@@ -1,18 +1,19 @@
+import itertools
 import warnings
 
-import six
-from six import iteritems, itervalues
-
 from mongoengine.base.common import _document_registry
 from mongoengine.base.fields import BaseField, ComplexBaseField, ObjectIdField
 from mongoengine.common import _import_class
 from mongoengine.errors import InvalidDocumentError
-from mongoengine.queryset import (DO_NOTHING, DoesNotExist,
+from mongoengine.queryset import (
-                                  MultipleObjectsReturned,
+    DO_NOTHING,
-                                  QuerySetManager)
+    DoesNotExist,
+    MultipleObjectsReturned,
+    QuerySetManager,
+)
 
 
-__all__ = ('DocumentMetaclass', 'TopLevelDocumentMetaclass')
+__all__ = ("DocumentMetaclass", "TopLevelDocumentMetaclass")
 
 
 class DocumentMetaclass(type):
@@ -21,49 +22,51 @@ class DocumentMetaclass(type):
     # TODO lower complexity of this method
     def __new__(mcs, name, bases, attrs):
         flattened_bases = mcs._get_bases(bases)
-        super_new = super(DocumentMetaclass, mcs).__new__
+        super_new = super().__new__
 
         # If a base class just call super
-        metaclass = attrs.get('my_metaclass')
+        metaclass = attrs.get("my_metaclass")
         if metaclass and issubclass(metaclass, DocumentMetaclass):
             return super_new(mcs, name, bases, attrs)
 
-        attrs['_is_document'] = attrs.get('_is_document', False)
+        attrs["_is_document"] = attrs.get("_is_document", False)
-        attrs['_cached_reference_fields'] = []
+        attrs["_cached_reference_fields"] = []
 
         # EmbeddedDocuments could have meta data for inheritance
-        if 'meta' in attrs:
+        if "meta" in attrs:
-            attrs['_meta'] = attrs.pop('meta')
+            attrs["_meta"] = attrs.pop("meta")
 
         # EmbeddedDocuments should inherit meta data
-        if '_meta' not in attrs:
+        if "_meta" not in attrs:
             meta = MetaDict()
             for base in flattened_bases[::-1]:
                 # Add any mixin metadata from plain objects
-                if hasattr(base, 'meta'):
+                if hasattr(base, "meta"):
                     meta.merge(base.meta)
-                elif hasattr(base, '_meta'):
+                elif hasattr(base, "_meta"):
                     meta.merge(base._meta)
-            attrs['_meta'] = meta
+            attrs["_meta"] = meta
-            attrs['_meta']['abstract'] = False  # 789: EmbeddedDocument shouldn't inherit abstract
+            attrs["_meta"][
+                "abstract"
+            ] = False  # 789: EmbeddedDocument shouldn't inherit abstract
 
         # If allow_inheritance is True, add a "_cls" string field to the attrs
-        if attrs['_meta'].get('allow_inheritance'):
+        if attrs["_meta"].get("allow_inheritance"):
-            StringField = _import_class('StringField')
+            StringField = _import_class("StringField")
-            attrs['_cls'] = StringField()
+            attrs["_cls"] = StringField()
 
         # Handle document Fields
 
         # Merge all fields from subclasses
         doc_fields = {}
         for base in flattened_bases[::-1]:
-            if hasattr(base, '_fields'):
+            if hasattr(base, "_fields"):
                 doc_fields.update(base._fields)
 
             # Standard object mixin - merge in any Fields
-            if not hasattr(base, '_meta'):
+            if not hasattr(base, "_meta"):
                 base_fields = {}
-                for attr_name, attr_value in iteritems(base.__dict__):
+                for attr_name, attr_value in base.__dict__.items():
                     if not isinstance(attr_value, BaseField):
                         continue
                     attr_value.name = attr_name
@@ -75,7 +78,7 @@ class DocumentMetaclass(type):
 
         # Discover any document fields
         field_names = {}
-        for attr_name, attr_value in iteritems(attrs):
+        for attr_name, attr_value in attrs.items():
             if not isinstance(attr_value, BaseField):
                 continue
             attr_value.name = attr_name
@@ -84,27 +87,29 @@ class DocumentMetaclass(type):
             doc_fields[attr_name] = attr_value
 
             # Count names to ensure no db_field redefinitions
-            field_names[attr_value.db_field] = field_names.get(
+            field_names[attr_value.db_field] = (
-                attr_value.db_field, 0) + 1
+                field_names.get(attr_value.db_field, 0) + 1
+            )
 
         # Ensure no duplicate db_fields
         duplicate_db_fields = [k for k, v in field_names.items() if v > 1]
         if duplicate_db_fields:
-            msg = ('Multiple db_fields defined for: %s ' %
+            msg = "Multiple db_fields defined for: %s " % ", ".join(duplicate_db_fields)
-                   ', '.join(duplicate_db_fields))
             raise InvalidDocumentError(msg)
 
         # Set _fields and db_field maps
-        attrs['_fields'] = doc_fields
+        attrs["_fields"] = doc_fields
-        attrs['_db_field_map'] = {k: getattr(v, 'db_field', k)
+        attrs["_db_field_map"] = {
-                                  for k, v in doc_fields.items()}
+            k: getattr(v, "db_field", k) for k, v in doc_fields.items()
-        attrs['_reverse_db_field_map'] = {
+        }
-            v: k for k, v in attrs['_db_field_map'].items()
+        attrs["_reverse_db_field_map"] = {
+            v: k for k, v in attrs["_db_field_map"].items()
         }
 
-        attrs['_fields_ordered'] = tuple(i[1] for i in sorted(
+        attrs["_fields_ordered"] = tuple(
-                                         (v.creation_counter, v.name)
+            i[1]
-                                         for v in itervalues(doc_fields)))
+            for i in sorted((v.creation_counter, v.name) for v in doc_fields.values())
+        )
 
         #
         # Set document hierarchy
@@ -112,32 +117,34 @@ class DocumentMetaclass(type):
         superclasses = ()
         class_name = [name]
         for base in flattened_bases:
-            if (not getattr(base, '_is_base_cls', True) and
+            if not getattr(base, "_is_base_cls", True) and not getattr(
-                    not getattr(base, '_meta', {}).get('abstract', True)):
+                base, "_meta", {}
+            ).get("abstract", True):
                 # Collate hierarchy for _cls and _subclasses
                 class_name.append(base.__name__)
 
-            if hasattr(base, '_meta'):
+            if hasattr(base, "_meta"):
                 # Warn if allow_inheritance isn't set and prevent
                 # inheritance of classes where inheritance is set to False
-                allow_inheritance = base._meta.get('allow_inheritance')
+                allow_inheritance = base._meta.get("allow_inheritance")
-                if not allow_inheritance and not base._meta.get('abstract'):
+                if not allow_inheritance and not base._meta.get("abstract"):
-                    raise ValueError('Document %s may not be subclassed. '
+                    raise ValueError(
-                                     'To enable inheritance, use the "allow_inheritance" meta attribute.' %
+                        "Document %s may not be subclassed. "
-                                     base.__name__)
+                        'To enable inheritance, use the "allow_inheritance" meta attribute.'
+                        % base.__name__
+                    )
 
         # Get superclasses from last base superclass
-        document_bases = [b for b in flattened_bases
+        document_bases = [b for b in flattened_bases if hasattr(b, "_class_name")]
-                          if hasattr(b, '_class_name')]
         if document_bases:
             superclasses = document_bases[0]._superclasses
-            superclasses += (document_bases[0]._class_name, )
+            superclasses += (document_bases[0]._class_name,)
 
-        _cls = '.'.join(reversed(class_name))
+        _cls = ".".join(reversed(class_name))
-        attrs['_class_name'] = _cls
+        attrs["_class_name"] = _cls
-        attrs['_superclasses'] = superclasses
+        attrs["_superclasses"] = superclasses
-        attrs['_subclasses'] = (_cls, )
+        attrs["_subclasses"] = (_cls,)
-        attrs['_types'] = attrs['_subclasses']  # TODO depreciate _types
+        attrs["_types"] = attrs["_subclasses"]  # TODO depreciate _types
 
         # Create the new_class
         new_class = super_new(mcs, name, bases, attrs)
@@ -148,8 +155,12 @@ class DocumentMetaclass(type):
                 base._subclasses += (_cls,)
             base._types = base._subclasses  # TODO depreciate _types
 
-        (Document, EmbeddedDocument, DictField,
+        (
-         CachedReferenceField) = mcs._import_classes()
+            Document,
+            EmbeddedDocument,
+            DictField,
+            CachedReferenceField,
+        ) = mcs._import_classes()
 
         if issubclass(new_class, Document):
             new_class._collection = None
@@ -157,63 +168,50 @@ class DocumentMetaclass(type):
         # Add class to the _document_registry
         _document_registry[new_class._class_name] = new_class
 
-        # In Python 2, User-defined methods objects have special read-only
-        # attributes 'im_func' and 'im_self' which contain the function obj
-        # and class instance object respectively.  With Python 3 these special
-        # attributes have been replaced by __func__ and __self__.  The Blinker
-        # module continues to use im_func and im_self, so the code below
-        # copies __func__ into im_func and __self__ into im_self for
-        # classmethod objects in Document derived classes.
-        if six.PY3:
-            for val in new_class.__dict__.values():
-                if isinstance(val, classmethod):
-                    f = val.__get__(new_class)
-                    if hasattr(f, '__func__') and not hasattr(f, 'im_func'):
-                        f.__dict__.update({'im_func': getattr(f, '__func__')})
-                    if hasattr(f, '__self__') and not hasattr(f, 'im_self'):
-                        f.__dict__.update({'im_self': getattr(f, '__self__')})
-
         # Handle delete rules
-        for field in itervalues(new_class._fields):
+        for field in new_class._fields.values():
             f = field
             if f.owner_document is None:
                 f.owner_document = new_class
-            delete_rule = getattr(f, 'reverse_delete_rule', DO_NOTHING)
+            delete_rule = getattr(f, "reverse_delete_rule", DO_NOTHING)
             if isinstance(f, CachedReferenceField):
 
                 if issubclass(new_class, EmbeddedDocument):
-                    raise InvalidDocumentError('CachedReferenceFields is not '
+                    raise InvalidDocumentError(
-                                               'allowed in EmbeddedDocuments')
+                        "CachedReferenceFields is not allowed in EmbeddedDocuments"
+                    )
 
                 if f.auto_sync:
                     f.start_listener()
 
                 f.document_type._cached_reference_fields.append(f)
 
-            if isinstance(f, ComplexBaseField) and hasattr(f, 'field'):
+            if isinstance(f, ComplexBaseField) and hasattr(f, "field"):
-                delete_rule = getattr(f.field,
+                delete_rule = getattr(f.field, "reverse_delete_rule", DO_NOTHING)
-                                      'reverse_delete_rule',
-                                      DO_NOTHING)
                 if isinstance(f, DictField) and delete_rule != DO_NOTHING:
-                    msg = ('Reverse delete rules are not supported '
+                    msg = (
-                           'for %s (field: %s)' %
+                        "Reverse delete rules are not supported "
-                           (field.__class__.__name__, field.name))
+                        "for %s (field: %s)" % (field.__class__.__name__, field.name)
+                    )
                     raise InvalidDocumentError(msg)
 
                 f = field.field
 
             if delete_rule != DO_NOTHING:
                 if issubclass(new_class, EmbeddedDocument):
-                    msg = ('Reverse delete rules are not supported for '
+                    msg = (
-                           'EmbeddedDocuments (field: %s)' % field.name)
+                        "Reverse delete rules are not supported for "
+                        "EmbeddedDocuments (field: %s)" % field.name
+                    )
                     raise InvalidDocumentError(msg)
-                f.document_type.register_delete_rule(new_class,
+                f.document_type.register_delete_rule(new_class, field.name, delete_rule)
-                                                     field.name, delete_rule)
 
-            if (field.name and hasattr(Document, field.name) and
+            if (
-                    EmbeddedDocument not in new_class.mro()):
+                field.name
-                msg = ('%s is a document method and not a valid '
+                and hasattr(Document, field.name)
-                       'field name' % field.name)
+                and EmbeddedDocument not in new_class.mro()
+            ):
+                msg = "%s is a document method and not a valid field name" % field.name
                 raise InvalidDocumentError(msg)
 
         return new_class
@@ -233,15 +231,14 @@ class DocumentMetaclass(type):
             if base is object:
                 continue
             yield base
-            for child_base in mcs.__get_bases(base.__bases__):
+            yield from mcs.__get_bases(base.__bases__)
-                yield child_base
 
     @classmethod
     def _import_classes(mcs):
-        Document = _import_class('Document')
+        Document = _import_class("Document")
-        EmbeddedDocument = _import_class('EmbeddedDocument')
+        EmbeddedDocument = _import_class("EmbeddedDocument")
-        DictField = _import_class('DictField')
+        DictField = _import_class("DictField")
-        CachedReferenceField = _import_class('CachedReferenceField')
+        CachedReferenceField = _import_class("CachedReferenceField")
         return Document, EmbeddedDocument, DictField, CachedReferenceField
 
 
@@ -252,68 +249,69 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
 
     def __new__(mcs, name, bases, attrs):
         flattened_bases = mcs._get_bases(bases)
-        super_new = super(TopLevelDocumentMetaclass, mcs).__new__
+        super_new = super().__new__
 
         # Set default _meta data if base class, otherwise get user defined meta
-        if attrs.get('my_metaclass') == TopLevelDocumentMetaclass:
+        if attrs.get("my_metaclass") == TopLevelDocumentMetaclass:
             # defaults
-            attrs['_meta'] = {
+            attrs["_meta"] = {
-                'abstract': True,
+                "abstract": True,
-                'max_documents': None,
+                "max_documents": None,
-                'max_size': None,
+                "max_size": None,
-                'ordering': [],  # default ordering applied at runtime
+                "ordering": [],  # default ordering applied at runtime
-                'indexes': [],  # indexes to be ensured at runtime
+                "indexes": [],  # indexes to be ensured at runtime
-                'id_field': None,
+                "id_field": None,
-                'index_background': False,
+                "index_background": False,
-                'index_drop_dups': False,
+                "index_opts": None,
-                'index_opts': None,
+                "delete_rules": None,
-                'delete_rules': None,
-
                 # allow_inheritance can be True, False, and None. True means
                 # "allow inheritance", False means "don't allow inheritance",
                 # None means "do whatever your parent does, or don't allow
                 # inheritance if you're a top-level class".
-                'allow_inheritance': None,
+                "allow_inheritance": None,
             }
-            attrs['_is_base_cls'] = True
+            attrs["_is_base_cls"] = True
-            attrs['_meta'].update(attrs.get('meta', {}))
+            attrs["_meta"].update(attrs.get("meta", {}))
         else:
-            attrs['_meta'] = attrs.get('meta', {})
+            attrs["_meta"] = attrs.get("meta", {})
             # Explicitly set abstract to false unless set
-            attrs['_meta']['abstract'] = attrs['_meta'].get('abstract', False)
+            attrs["_meta"]["abstract"] = attrs["_meta"].get("abstract", False)
-            attrs['_is_base_cls'] = False
+            attrs["_is_base_cls"] = False
 
         # Set flag marking as document class - as opposed to an object mixin
-        attrs['_is_document'] = True
+        attrs["_is_document"] = True
 
         # Ensure queryset_class is inherited
-        if 'objects' in attrs:
+        if "objects" in attrs:
-            manager = attrs['objects']
+            manager = attrs["objects"]
-            if hasattr(manager, 'queryset_class'):
+            if hasattr(manager, "queryset_class"):
-                attrs['_meta']['queryset_class'] = manager.queryset_class
+                attrs["_meta"]["queryset_class"] = manager.queryset_class
 
         # Clean up top level meta
-        if 'meta' in attrs:
+        if "meta" in attrs:
-            del attrs['meta']
+            del attrs["meta"]
 
         # Find the parent document class
-        parent_doc_cls = [b for b in flattened_bases
+        parent_doc_cls = [
-                          if b.__class__ == TopLevelDocumentMetaclass]
+            b for b in flattened_bases if b.__class__ == TopLevelDocumentMetaclass
+        ]
         parent_doc_cls = None if not parent_doc_cls else parent_doc_cls[0]
 
         # Prevent classes setting collection different to their parents
         # If parent wasn't an abstract class
-        if (parent_doc_cls and 'collection' in attrs.get('_meta', {}) and
+        if (
-                not parent_doc_cls._meta.get('abstract', True)):
+            parent_doc_cls
-            msg = 'Trying to set a collection on a subclass (%s)' % name
+            and "collection" in attrs.get("_meta", {})
+            and not parent_doc_cls._meta.get("abstract", True)
+        ):
+            msg = "Trying to set a collection on a subclass (%s)" % name
             warnings.warn(msg, SyntaxWarning)
-            del attrs['_meta']['collection']
+            del attrs["_meta"]["collection"]
 
         # Ensure abstract documents have abstract bases
-        if attrs.get('_is_base_cls') or attrs['_meta'].get('abstract'):
+        if attrs.get("_is_base_cls") or attrs["_meta"].get("abstract"):
-            if (parent_doc_cls and
+            if parent_doc_cls and not parent_doc_cls._meta.get("abstract", False):
-                    not parent_doc_cls._meta.get('abstract', False)):
+                msg = "Abstract document cannot have non-abstract base"
-                msg = 'Abstract document cannot have non-abstract base'
                 raise ValueError(msg)
             return super_new(mcs, name, bases, attrs)
 
@@ -322,38 +320,43 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
         meta = MetaDict()
         for base in flattened_bases[::-1]:
             # Add any mixin metadata from plain objects
-            if hasattr(base, 'meta'):
+            if hasattr(base, "meta"):
                 meta.merge(base.meta)
-            elif hasattr(base, '_meta'):
+            elif hasattr(base, "_meta"):
                 meta.merge(base._meta)
 
             # Set collection in the meta if its callable
-            if (getattr(base, '_is_document', False) and
+            if getattr(base, "_is_document", False) and not base._meta.get("abstract"):
-                    not base._meta.get('abstract')):
+                collection = meta.get("collection", None)
-                collection = meta.get('collection', None)
                 if callable(collection):
-                    meta['collection'] = collection(base)
+                    meta["collection"] = collection(base)
 
-        meta.merge(attrs.get('_meta', {}))  # Top level meta
+        meta.merge(attrs.get("_meta", {}))  # Top level meta
 
         # Only simple classes (i.e. direct subclasses of Document) may set
         # allow_inheritance to False. If the base Document allows inheritance,
         # none of its subclasses can override allow_inheritance to False.
-        simple_class = all([b._meta.get('abstract')
+        simple_class = all(
-                            for b in flattened_bases if hasattr(b, '_meta')])
+            [b._meta.get("abstract") for b in flattened_bases if hasattr(b, "_meta")]
+        )
         if (
-            not simple_class and
+            not simple_class
-            meta['allow_inheritance'] is False and
+            and meta["allow_inheritance"] is False
-            not meta['abstract']
+            and not meta["abstract"]
         ):
-            raise ValueError('Only direct subclasses of Document may set '
+            raise ValueError(
-                             '"allow_inheritance" to False')
+                "Only direct subclasses of Document may set "
+                '"allow_inheritance" to False'
+            )
 
         # Set default collection name
-        if 'collection' not in meta:
+        if "collection" not in meta:
-            meta['collection'] = ''.join('_%s' % c if c.isupper() else c
+            meta["collection"] = (
-                                         for c in name).strip('_').lower()
+                "".join("_%s" % c if c.isupper() else c for c in name)
-        attrs['_meta'] = meta
+                .strip("_")
+                .lower()
+            )
+        attrs["_meta"] = meta
 
         # Call super and get the new class
         new_class = super_new(mcs, name, bases, attrs)
@@ -361,82 +364,96 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
         meta = new_class._meta
 
         # Set index specifications
-        meta['index_specs'] = new_class._build_index_specs(meta['indexes'])
+        meta["index_specs"] = new_class._build_index_specs(meta["indexes"])
 
         # If collection is a callable - call it and set the value
-        collection = meta.get('collection')
+        collection = meta.get("collection")
         if callable(collection):
-            new_class._meta['collection'] = collection(new_class)
+            new_class._meta["collection"] = collection(new_class)
 
         # Provide a default queryset unless exists or one has been set
-        if 'objects' not in dir(new_class):
+        if "objects" not in dir(new_class):
             new_class.objects = QuerySetManager()
 
         # Validate the fields and set primary key if needed
-        for field_name, field in iteritems(new_class._fields):
+        for field_name, field in new_class._fields.items():
             if field.primary_key:
                 # Ensure only one primary key is set
-                current_pk = new_class._meta.get('id_field')
+                current_pk = new_class._meta.get("id_field")
                 if current_pk and current_pk != field_name:
-                    raise ValueError('Cannot override primary key field')
+                    raise ValueError("Cannot override primary key field")
 
                 # Set primary key
                 if not current_pk:
-                    new_class._meta['id_field'] = field_name
+                    new_class._meta["id_field"] = field_name
                     new_class.id = field
 
-        # Set primary key if not defined by the document
+        # If the document doesn't explicitly define a primary key field, create
-        new_class._auto_id_field = getattr(parent_doc_cls,
+        # one. Make it an ObjectIdField and give it a non-clashing name ("id"
-                                           '_auto_id_field', False)
+        # by default, but can be different if that one's taken).
-        if not new_class._meta.get('id_field'):
+        if not new_class._meta.get("id_field"):
-            # After 0.10, find not existing names, instead of overwriting
             id_name, id_db_name = mcs.get_auto_id_names(new_class)
-            new_class._auto_id_field = True
+            new_class._meta["id_field"] = id_name
-            new_class._meta['id_field'] = id_name
             new_class._fields[id_name] = ObjectIdField(db_field=id_db_name)
             new_class._fields[id_name].name = id_name
             new_class.id = new_class._fields[id_name]
             new_class._db_field_map[id_name] = id_db_name
             new_class._reverse_db_field_map[id_db_name] = id_name
-            # Prepend id field to _fields_ordered
-            new_class._fields_ordered = (id_name, ) + new_class._fields_ordered
 
-        # Merge in exceptions with parent hierarchy
+            # Prepend the ID field to _fields_ordered (so that it's *always*
+            # the first field).
+            new_class._fields_ordered = (id_name,) + new_class._fields_ordered
+
+        # Merge in exceptions with parent hierarchy.
         exceptions_to_merge = (DoesNotExist, MultipleObjectsReturned)
-        module = attrs.get('__module__')
+        module = attrs.get("__module__")
         for exc in exceptions_to_merge:
             name = exc.__name__
-            parents = tuple(getattr(base, name) for base in flattened_bases
+            parents = tuple(
-                            if hasattr(base, name)) or (exc,)
+                getattr(base, name) for base in flattened_bases if hasattr(base, name)
-            # Create new exception and set to new_class
+            ) or (exc,)
-            exception = type(name, parents, {'__module__': module})
+
+            # Create a new exception and set it as an attribute on the new
+            # class.
+            exception = type(name, parents, {"__module__": module})
             setattr(new_class, name, exception)
 
         return new_class
 
     @classmethod
     def get_auto_id_names(mcs, new_class):
-        id_name, id_db_name = ('id', '_id')
+        """Find a name for the automatic ID field for the given new class.
-        if id_name not in new_class._fields and \
+
-                id_db_name not in (v.db_field for v in new_class._fields.values()):
+        Return a two-element tuple where the first item is the field name (i.e.
+        the attribute name on the object) and the second element is the DB
+        field name (i.e. the name of the key stored in MongoDB).
+
+        Defaults to ('id', '_id'), or generates a non-clashing name in the form
+        of ('auto_id_X', '_auto_id_X') if the default name is already taken.
+        """
+        id_name, id_db_name = ("id", "_id")
+        existing_fields = {field_name for field_name in new_class._fields}
+        existing_db_fields = {v.db_field for v in new_class._fields.values()}
+        if id_name not in existing_fields and id_db_name not in existing_db_fields:
             return id_name, id_db_name
-        id_basename, id_db_basename, i = 'auto_id', '_auto_id', 0
+
-        while id_name in new_class._fields or \
+        id_basename, id_db_basename, i = ("auto_id", "_auto_id", 0)
-                id_db_name in (v.db_field for v in new_class._fields.values()):
+        for i in itertools.count():
-            id_name = '{0}_{1}'.format(id_basename, i)
+            id_name = "{}_{}".format(id_basename, i)
-            id_db_name = '{0}_{1}'.format(id_db_basename, i)
+            id_db_name = "{}_{}".format(id_db_basename, i)
-            i += 1
+            if id_name not in existing_fields and id_db_name not in existing_db_fields:
-        return id_name, id_db_name
+                return id_name, id_db_name
 
 
 class MetaDict(dict):
     """Custom dictionary for meta classes.
     Handles the merging of set indexes
     """
-    _merge_options = ('indexes',)
+
+    _merge_options = ("indexes",)
 
     def merge(self, new_options):
-        for k, v in iteritems(new_options):
+        for k, v in new_options.items():
             if k in self._merge_options:
                 self[k] = self.get(k, []) + v
             else:
@@ -445,4 +462,5 @@ class MetaDict(dict):
 
 class BasesTuple(tuple):
     """Special class to handle introspection of bases tuple in __new__"""
+
     pass

mongoengine/base/utils.py

@@ -1,7 +1,7 @@
 import re
 
 
-class LazyRegexCompiler(object):
+class LazyRegexCompiler:
     """Descriptor to allow lazy compilation of regex"""
 
     def __init__(self, pattern, flags=0):

mongoengine/common.py

@@ -19,34 +19,44 @@ def _import_class(cls_name):
     if cls_name in _class_registry_cache:
         return _class_registry_cache.get(cls_name)
 
-    doc_classes = ('Document', 'DynamicEmbeddedDocument', 'EmbeddedDocument',
+    doc_classes = (
-                   'MapReduceDocument')
+        "Document",
+        "DynamicEmbeddedDocument",
+        "EmbeddedDocument",
+        "MapReduceDocument",
+    )
 
     # Field Classes
     if not _field_list_cache:
         from mongoengine.fields import __all__ as fields
+
         _field_list_cache.extend(fields)
         from mongoengine.base.fields import __all__ as fields
+
         _field_list_cache.extend(fields)
 
     field_classes = _field_list_cache
 
-    deref_classes = ('DeReference',)
+    deref_classes = ("DeReference",)
 
-    if cls_name == 'BaseDocument':
+    if cls_name == "BaseDocument":
         from mongoengine.base import document as module
-        import_classes = ['BaseDocument']
+
+        import_classes = ["BaseDocument"]
     elif cls_name in doc_classes:
         from mongoengine import document as module
+
         import_classes = doc_classes
     elif cls_name in field_classes:
         from mongoengine import fields as module
+
         import_classes = field_classes
     elif cls_name in deref_classes:
         from mongoengine import dereference as module
+
         import_classes = deref_classes
     else:
-        raise ValueError('No import set for: %s' % cls_name)
+        raise ValueError("No import set for: %s" % cls_name)
 
     for cls in import_classes:
         _class_registry_cache[cls] = getattr(module, cls)

mongoengine/connection.py

@@ -1,23 +1,22 @@
 from pymongo import MongoClient, ReadPreference, uri_parser
 from pymongo.database import _check_name
-import six
 
 __all__ = [
-    'DEFAULT_CONNECTION_NAME',
+    "DEFAULT_CONNECTION_NAME",
-    'DEFAULT_DATABASE_NAME',
+    "DEFAULT_DATABASE_NAME",
-    'MongoEngineConnectionError',
+    "ConnectionFailure",
-    'connect',
+    "connect",
-    'disconnect',
+    "disconnect",
-    'disconnect_all',
+    "disconnect_all",
-    'get_connection',
+    "get_connection",
-    'get_db',
+    "get_db",
-    'register_connection',
+    "register_connection",
 ]
 
 
-DEFAULT_CONNECTION_NAME = 'default'
+DEFAULT_CONNECTION_NAME = "default"
-DEFAULT_DATABASE_NAME = 'test'
+DEFAULT_DATABASE_NAME = "test"
-DEFAULT_HOST = 'localhost'
+DEFAULT_HOST = "localhost"
 DEFAULT_PORT = 27017
 
 _connection_settings = {}
@@ -27,10 +26,11 @@ _dbs = {}
 READ_PREFERENCE = ReadPreference.PRIMARY
 
 
-class MongoEngineConnectionError(Exception):
+class ConnectionFailure(Exception):
     """Error raised when the database connection can't be established or
     when a connection with a requested alias can't be retrieved.
     """
+
     pass
 
 
@@ -38,19 +38,24 @@ def _check_db_name(name):
     """Check if a database name is valid.
     This functionality is copied from pymongo Database class constructor.
     """
-    if not isinstance(name, six.string_types):
+    if not isinstance(name, str):
-        raise TypeError('name must be an instance of %s' % six.string_types)
+        raise TypeError("name must be an instance of %s" % str)
-    elif name != '$external':
+    elif name != "$external":
         _check_name(name)
 
 
 def _get_connection_settings(
-        db=None, name=None, host=None, port=None,
+    db=None,
-        read_preference=READ_PREFERENCE,
+    name=None,
-        username=None, password=None,
+    host=None,
-        authentication_source=None,
+    port=None,
-        authentication_mechanism=None,
+    read_preference=READ_PREFERENCE,
-        **kwargs):
+    username=None,
+    password=None,
+    authentication_source=None,
+    authentication_mechanism=None,
+    **kwargs
+):
     """Get the connection settings as a dict
 
     : param db: the name of the database to use, for compatibility with connect
@@ -73,53 +78,61 @@ def _get_connection_settings(
     .. versionchanged:: 0.10.6 - added mongomock support
     """
     conn_settings = {
-        'name': name or db or DEFAULT_DATABASE_NAME,
+        "name": name or db or DEFAULT_DATABASE_NAME,
-        'host': host or DEFAULT_HOST,
+        "host": host or DEFAULT_HOST,
-        'port': port or DEFAULT_PORT,
+        "port": port or DEFAULT_PORT,
-        'read_preference': read_preference,
+        "read_preference": read_preference,
-        'username': username,
+        "username": username,
-        'password': password,
+        "password": password,
-        'authentication_source': authentication_source,
+        "authentication_source": authentication_source,
-        'authentication_mechanism': authentication_mechanism
+        "authentication_mechanism": authentication_mechanism,
     }
 
-    _check_db_name(conn_settings['name'])
+    _check_db_name(conn_settings["name"])
-    conn_host = conn_settings['host']
+    conn_host = conn_settings["host"]
 
     # Host can be a list or a string, so if string, force to a list.
-    if isinstance(conn_host, six.string_types):
+    if isinstance(conn_host, str):
         conn_host = [conn_host]
 
     resolved_hosts = []
     for entity in conn_host:
 
         # Handle Mongomock
-        if entity.startswith('mongomock://'):
+        if entity.startswith("mongomock://"):
-            conn_settings['is_mock'] = True
+            conn_settings["is_mock"] = True
             # `mongomock://` is not a valid url prefix and must be replaced by `mongodb://`
-            resolved_hosts.append(entity.replace('mongomock://', 'mongodb://', 1))
+            new_entity = entity.replace("mongomock://", "mongodb://", 1)
+            resolved_hosts.append(new_entity)
+
+            uri_dict = uri_parser.parse_uri(new_entity)
+
+            database = uri_dict.get("database")
+            if database:
+                conn_settings["name"] = database
 
         # Handle URI style connections, only updating connection params which
         # were explicitly specified in the URI.
-        elif '://' in entity:
+        elif "://" in entity:
             uri_dict = uri_parser.parse_uri(entity)
             resolved_hosts.append(entity)
 
-            if uri_dict.get('database'):
+            database = uri_dict.get("database")
-                conn_settings['name'] = uri_dict.get('database')
+            if database:
+                conn_settings["name"] = database
 
-            for param in ('read_preference', 'username', 'password'):
+            for param in ("read_preference", "username", "password"):
                 if uri_dict.get(param):
                     conn_settings[param] = uri_dict[param]
 
-            uri_options = uri_dict['options']
+            uri_options = uri_dict["options"]
-            if 'replicaset' in uri_options:
+            if "replicaset" in uri_options:
-                conn_settings['replicaSet'] = uri_options['replicaset']
+                conn_settings["replicaSet"] = uri_options["replicaset"]
-            if 'authsource' in uri_options:
+            if "authsource" in uri_options:
-                conn_settings['authentication_source'] = uri_options['authsource']
+                conn_settings["authentication_source"] = uri_options["authsource"]
-            if 'authmechanism' in uri_options:
+            if "authmechanism" in uri_options:
-                conn_settings['authentication_mechanism'] = uri_options['authmechanism']
+                conn_settings["authentication_mechanism"] = uri_options["authmechanism"]
-            if 'readpreference' in uri_options:
+            if "readpreference" in uri_options:
                 read_preferences = (
                     ReadPreference.NEAREST,
                     ReadPreference.PRIMARY,
@@ -133,40 +146,47 @@ def _get_connection_settings(
                 # int (e.g. 3).
                 # TODO simplify the code below once we drop support for
                 # PyMongo v3.4.
-                read_pf_mode = uri_options['readpreference']
+                read_pf_mode = uri_options["readpreference"]
-                if isinstance(read_pf_mode, six.string_types):
+                if isinstance(read_pf_mode, str):
                     read_pf_mode = read_pf_mode.lower()
                 for preference in read_preferences:
                     if (
-                        preference.name.lower() == read_pf_mode or
+                        preference.name.lower() == read_pf_mode
-                        preference.mode == read_pf_mode
+                        or preference.mode == read_pf_mode
                     ):
-                        conn_settings['read_preference'] = preference
+                        conn_settings["read_preference"] = preference
                         break
         else:
             resolved_hosts.append(entity)
-    conn_settings['host'] = resolved_hosts
+    conn_settings["host"] = resolved_hosts
 
     # Deprecated parameters that should not be passed on
-    kwargs.pop('slaves', None)
+    kwargs.pop("slaves", None)
-    kwargs.pop('is_slave', None)
+    kwargs.pop("is_slave", None)
 
     conn_settings.update(kwargs)
     return conn_settings
 
 
-def register_connection(alias, db=None, name=None, host=None, port=None,
+def register_connection(
-                        read_preference=READ_PREFERENCE,
+    alias,
-                        username=None, password=None,
+    db=None,
-                        authentication_source=None,
+    name=None,
-                        authentication_mechanism=None,
+    host=None,
-                        **kwargs):
+    port=None,
+    read_preference=READ_PREFERENCE,
+    username=None,
+    password=None,
+    authentication_source=None,
+    authentication_mechanism=None,
+    **kwargs
+):
     """Register the connection settings.
 
     : param alias: the name that will be used to refer to this connection
         throughout MongoEngine
-    : param name: the name of the specific database to use
     : param db: the name of the database to use, for compatibility with connect
+    : param name: the name of the specific database to use
     : param host: the host name of the: program: `mongod` instance to connect to
     : param port: the port that the: program: `mongod` instance is running on
     : param read_preference: The read preference for the collection
@@ -185,12 +205,17 @@ def register_connection(alias, db=None, name=None, host=None, port=None,
     .. versionchanged:: 0.10.6 - added mongomock support
     """
     conn_settings = _get_connection_settings(
-        db=db, name=name, host=host, port=port,
+        db=db,
+        name=name,
+        host=host,
+        port=port,
         read_preference=read_preference,
-        username=username, password=password,
+        username=username,
+        password=password,
         authentication_source=authentication_source,
         authentication_mechanism=authentication_mechanism,
-        **kwargs)
+        **kwargs
+    )
     _connection_settings[alias] = conn_settings
 
 
@@ -206,7 +231,7 @@ def disconnect(alias=DEFAULT_CONNECTION_NAME):
     if alias in _dbs:
         # Detach all cached collections in Documents
         for doc_cls in _get_documents_by_db(alias, DEFAULT_CONNECTION_NAME):
-            if issubclass(doc_cls, Document):     # Skip EmbeddedDocument
+            if issubclass(doc_cls, Document):  # Skip EmbeddedDocument
                 doc_cls._disconnect()
 
         del _dbs[alias]
@@ -234,22 +259,24 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
         return _connections[alias]
 
     # Validate that the requested alias exists in the _connection_settings.
-    # Raise MongoEngineConnectionError if it doesn't.
+    # Raise ConnectionFailure if it doesn't.
     if alias not in _connection_settings:
         if alias == DEFAULT_CONNECTION_NAME:
-            msg = 'You have not defined a default connection'
+            msg = "You have not defined a default connection"
         else:
             msg = 'Connection with alias "%s" has not been defined' % alias
-        raise MongoEngineConnectionError(msg)
+        raise ConnectionFailure(msg)
 
     def _clean_settings(settings_dict):
         irrelevant_fields_set = {
-            'name', 'username', 'password',
+            "name",
-            'authentication_source', 'authentication_mechanism'
+            "username",
+            "password",
+            "authentication_source",
+            "authentication_mechanism",
         }
         return {
-            k: v for k, v in settings_dict.items()
+            k: v for k, v in settings_dict.items() if k not in irrelevant_fields_set
-            if k not in irrelevant_fields_set
         }
 
     raw_conn_settings = _connection_settings[alias].copy()
@@ -260,13 +287,12 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
     conn_settings = _clean_settings(raw_conn_settings)
 
     # Determine if we should use PyMongo's or mongomock's MongoClient.
-    is_mock = conn_settings.pop('is_mock', False)
+    is_mock = conn_settings.pop("is_mock", False)
     if is_mock:
         try:
             import mongomock
         except ImportError:
-            raise RuntimeError('You need mongomock installed to mock '
+            raise RuntimeError("You need mongomock installed to mock MongoEngine.")
-                               'MongoEngine.')
         connection_class = mongomock.MongoClient
     else:
         connection_class = MongoClient
@@ -277,9 +303,7 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
         connection = existing_connection
     else:
         connection = _create_connection(
-            alias=alias,
+            alias=alias, connection_class=connection_class, **conn_settings
-            connection_class=connection_class,
-            **conn_settings
         )
     _connections[alias] = connection
     return _connections[alias]
@@ -288,13 +312,12 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
 def _create_connection(alias, connection_class, **connection_settings):
     """
     Create the new connection for this alias. Raise
-    MongoEngineConnectionError if it can't be established.
+    ConnectionFailure if it can't be established.
     """
     try:
         return connection_class(**connection_settings)
     except Exception as e:
-        raise MongoEngineConnectionError(
+        raise ConnectionFailure("Cannot connect to database {} :\n{}".format(alias, e))
-            'Cannot connect to database %s :\n%s' % (alias, e))
 
 
 def _find_existing_connection(connection_settings):
@@ -316,7 +339,7 @@ def _find_existing_connection(connection_settings):
         # Only remove the name but it's important to
         # keep the username/password/authentication_source/authentication_mechanism
         # to identify if the connection could be shared (cfr https://github.com/MongoEngine/mongoengine/issues/2047)
-        return {k: v for k, v in settings_dict.items() if k != 'name'}
+        return {k: v for k, v in settings_dict.items() if k != "name"}
 
     cleaned_conn_settings = _clean_settings(connection_settings)
     for db_alias, connection_settings in connection_settings_bis:
@@ -332,14 +355,18 @@ def get_db(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
     if alias not in _dbs:
         conn = get_connection(alias)
         conn_settings = _connection_settings[alias]
-        db = conn[conn_settings['name']]
+        db = conn[conn_settings["name"]]
-        auth_kwargs = {'source': conn_settings['authentication_source']}
+        auth_kwargs = {"source": conn_settings["authentication_source"]}
-        if conn_settings['authentication_mechanism'] is not None:
+        if conn_settings["authentication_mechanism"] is not None:
-            auth_kwargs['mechanism'] = conn_settings['authentication_mechanism']
+            auth_kwargs["mechanism"] = conn_settings["authentication_mechanism"]
         # Authenticate if necessary
-        if conn_settings['username'] and (conn_settings['password'] or
+        if conn_settings["username"] and (
-                                          conn_settings['authentication_mechanism'] == 'MONGODB-X509'):
+            conn_settings["password"]
-            db.authenticate(conn_settings['username'], conn_settings['password'], **auth_kwargs)
+            or conn_settings["authentication_mechanism"] == "MONGODB-X509"
+        ):
+            db.authenticate(
+                conn_settings["username"], conn_settings["password"], **auth_kwargs
+            )
         _dbs[alias] = db
     return _dbs[alias]
 
@@ -368,10 +395,10 @@ def connect(db=None, alias=DEFAULT_CONNECTION_NAME, **kwargs):
 
         if new_conn_settings != prev_conn_setting:
             err_msg = (
-                u'A different connection with alias `{}` was already '
+                "A different connection with alias `{}` was already "
-                u'registered. Use disconnect() first'
+                "registered. Use disconnect() first"
             ).format(alias)
-            raise MongoEngineConnectionError(err_msg)
+            raise ConnectionFailure(err_msg)
     else:
         register_connection(alias, db, **kwargs)
 

mongoengine/context_managers.py

@@ -1,17 +1,24 @@
 from contextlib import contextmanager
 
+from pymongo.read_concern import ReadConcern
 from pymongo.write_concern import WriteConcern
-from six import iteritems
 
 from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.pymongo_support import count_documents
 
-__all__ = ('switch_db', 'switch_collection', 'no_dereference',
+__all__ = (
-           'no_sub_classes', 'query_counter', 'set_write_concern')
+    "switch_db",
+    "switch_collection",
+    "no_dereference",
+    "no_sub_classes",
+    "query_counter",
+    "set_write_concern",
+    "set_read_write_concern",
+)
 
 
-class switch_db(object):
+class switch_db:
     """switch_db alias context manager.
 
     Example ::
@@ -38,21 +45,21 @@ class switch_db(object):
         self.cls = cls
         self.collection = cls._get_collection()
         self.db_alias = db_alias
-        self.ori_db_alias = cls._meta.get('db_alias', DEFAULT_CONNECTION_NAME)
+        self.ori_db_alias = cls._meta.get("db_alias", DEFAULT_CONNECTION_NAME)
 
     def __enter__(self):
         """Change the db_alias and clear the cached collection."""
-        self.cls._meta['db_alias'] = self.db_alias
+        self.cls._meta["db_alias"] = self.db_alias
         self.cls._collection = None
         return self.cls
 
     def __exit__(self, t, value, traceback):
         """Reset the db_alias and collection."""
-        self.cls._meta['db_alias'] = self.ori_db_alias
+        self.cls._meta["db_alias"] = self.ori_db_alias
         self.cls._collection = self.collection
 
 
-class switch_collection(object):
+class switch_collection:
     """switch_collection alias context manager.
 
     Example ::
@@ -94,7 +101,7 @@ class switch_collection(object):
         self.cls._get_collection_name = self.ori_get_collection_name
 
 
-class no_dereference(object):
+class no_dereference:
     """no_dereference context manager.
 
     Turns off all dereferencing in Documents for the duration of the context
@@ -111,14 +118,15 @@ class no_dereference(object):
         """
         self.cls = cls
 
-        ReferenceField = _import_class('ReferenceField')
+        ReferenceField = _import_class("ReferenceField")
-        GenericReferenceField = _import_class('GenericReferenceField')
+        GenericReferenceField = _import_class("GenericReferenceField")
-        ComplexBaseField = _import_class('ComplexBaseField')
+        ComplexBaseField = _import_class("ComplexBaseField")
 
-        self.deref_fields = [k for k, v in iteritems(self.cls._fields)
+        self.deref_fields = [
-                             if isinstance(v, (ReferenceField,
+            k
-                                               GenericReferenceField,
+            for k, v in self.cls._fields.items()
-                                               ComplexBaseField))]
+            if isinstance(v, (ReferenceField, GenericReferenceField, ComplexBaseField))
+        ]
 
     def __enter__(self):
         """Change the objects default and _auto_dereference values."""
@@ -133,7 +141,7 @@ class no_dereference(object):
         return self.cls
 
 
-class no_sub_classes(object):
+class no_sub_classes:
     """no_sub_classes context manager.
 
     Only returns instances of this class and no sub (inherited) classes::
@@ -161,10 +169,10 @@ class no_sub_classes(object):
         self.cls._subclasses = self.cls_initial_subclasses
 
 
-class query_counter(object):
+class query_counter:
     """Query_counter context manager to get the number of queries.
     This works by updating the `profiling_level` of the database so that all queries get logged,
-    resetting the db.system.profile collection at the beginnig of the context and counting the new entries.
+    resetting the db.system.profile collection at the beginning of the context and counting the new entries.
 
     This was designed for debugging purpose. In fact it is a global counter so queries issued by other threads/processes
     can interfere with it
@@ -175,20 +183,17 @@ class query_counter(object):
     - Some queries are ignored by default by the counter (killcursors, db.system.indexes)
     """
 
-    def __init__(self):
+    def __init__(self, alias=DEFAULT_CONNECTION_NAME):
         """Construct the query_counter
         """
-        self.db = get_db()
+        self.db = get_db(alias=alias)
         self.initial_profiling_level = None
-        self._ctx_query_counter = 0             # number of queries issued by the context
+        self._ctx_query_counter = 0  # number of queries issued by the context
 
         self._ignored_query = {
-            'ns':
+            "ns": {"$ne": "%s.system.indexes" % self.db.name},
-                {'$ne': '%s.system.indexes' % self.db.name},
+            "op": {"$ne": "killcursors"},  # MONGODB < 3.2
-            'op':                       # MONGODB < 3.2
+            "command.killCursors": {"$exists": False},  # MONGODB >= 3.2
-                {'$ne': 'killcursors'},
-            'command.killCursors':      # MONGODB >= 3.2
-                {'$exists': False}
         }
 
     def _turn_on_profiling(self):
@@ -231,15 +236,20 @@ class query_counter(object):
 
     def __repr__(self):
         """repr query_counter as the number of queries."""
-        return u"%s" % self._get_count()
+        return "%s" % self._get_count()
 
     def _get_count(self):
         """Get the number of queries by counting the current number of entries in db.system.profile
         and substracting the queries issued by this context. In fact everytime this is called, 1 query is
         issued so we need to balance that
         """
-        count = count_documents(self.db.system.profile, self._ignored_query) - self._ctx_query_counter
+        count = (
-        self._ctx_query_counter += 1    # Account for the query we just issued to gather the information
+            count_documents(self.db.system.profile, self._ignored_query)
+            - self._ctx_query_counter
+        )
+        self._ctx_query_counter += (
+            1  # Account for the query we just issued to gather the information
+        )
         return count
 
 
@@ -248,3 +258,21 @@ def set_write_concern(collection, write_concerns):
     combined_concerns = dict(collection.write_concern.document.items())
     combined_concerns.update(write_concerns)
     yield collection.with_options(write_concern=WriteConcern(**combined_concerns))
+
+
+@contextmanager
+def set_read_write_concern(collection, write_concerns, read_concerns):
+    combined_write_concerns = dict(collection.write_concern.document.items())
+
+    if write_concerns is not None:
+        combined_write_concerns.update(write_concerns)
+
+    combined_read_concerns = dict(collection.read_concern.document.items())
+
+    if read_concerns is not None:
+        combined_read_concerns.update(read_concerns)
+
+    yield collection.with_options(
+        write_concern=WriteConcern(**combined_write_concerns),
+        read_concern=ReadConcern(**combined_read_concerns),
+    )

mongoengine/dereference.py

@@ -1,9 +1,12 @@
 from bson import DBRef, SON
-import six
-from six import iteritems
 
-from mongoengine.base import (BaseDict, BaseList, EmbeddedDocumentList,
+from mongoengine.base import (
-                              TopLevelDocumentMetaclass, get_document)
+    BaseDict,
+    BaseList,
+    EmbeddedDocumentList,
+    TopLevelDocumentMetaclass,
+    get_document,
+)
 from mongoengine.base.datastructures import LazyReference
 from mongoengine.connection import get_db
 from mongoengine.document import Document, EmbeddedDocument
@@ -11,7 +14,7 @@ from mongoengine.fields import DictField, ListField, MapField, ReferenceField
 from mongoengine.queryset import QuerySet
 
 
-class DeReference(object):
+class DeReference:
     def __call__(self, items, max_depth=1, instance=None, name=None):
         """
         Cheaply dereferences the items to a set depth.
@@ -25,7 +28,7 @@ class DeReference(object):
             :class:`~mongoengine.base.ComplexBaseField`
         :param get: A boolean determining if being called by __get__
         """
-        if items is None or isinstance(items, six.string_types):
+        if items is None or isinstance(items, str):
             return items
 
         # cheapest way to convert a queryset to a list
@@ -36,21 +39,23 @@ class DeReference(object):
         self.max_depth = max_depth
         doc_type = None
 
-        if instance and isinstance(instance, (Document, EmbeddedDocument,
+        if instance and isinstance(
-                                              TopLevelDocumentMetaclass)):
+            instance, (Document, EmbeddedDocument, TopLevelDocumentMetaclass)
+        ):
             doc_type = instance._fields.get(name)
-            while hasattr(doc_type, 'field'):
+            while hasattr(doc_type, "field"):
                 doc_type = doc_type.field
 
             if isinstance(doc_type, ReferenceField):
                 field = doc_type
                 doc_type = doc_type.document_type
-                is_list = not hasattr(items, 'items')
+                is_list = not hasattr(items, "items")
 
                 if is_list and all([i.__class__ == doc_type for i in items]):
                     return items
                 elif not is_list and all(
-                        [i.__class__ == doc_type for i in items.values()]):
+                    [i.__class__ == doc_type for i in items.values()]
+                ):
                     return items
                 elif not field.dbref:
                     # We must turn the ObjectIds into DBRefs
@@ -72,7 +77,7 @@ class DeReference(object):
 
                     def _get_items_from_dict(items):
                         new_items = {}
-                        for k, v in iteritems(items):
+                        for k, v in items.items():
                             value = v
                             if isinstance(v, list):
                                 value = _get_items_from_list(v)
@@ -83,7 +88,7 @@ class DeReference(object):
                             new_items[k] = value
                         return new_items
 
-                    if not hasattr(items, 'items'):
+                    if not hasattr(items, "items"):
                         items = _get_items_from_list(items)
                     else:
                         items = _get_items_from_dict(items)
@@ -113,20 +118,26 @@ class DeReference(object):
         depth += 1
         for item in iterator:
             if isinstance(item, (Document, EmbeddedDocument)):
-                for field_name, field in iteritems(item._fields):
+                for field_name, field in item._fields.items():
                     v = item._data.get(field_name, None)
                     if isinstance(v, LazyReference):
                         # LazyReference inherits DBRef but should not be dereferenced here !
                         continue
                     elif isinstance(v, DBRef):
                         reference_map.setdefault(field.document_type, set()).add(v.id)
-                    elif isinstance(v, (dict, SON)) and '_ref' in v:
+                    elif isinstance(v, (dict, SON)) and "_ref" in v:
-                        reference_map.setdefault(get_document(v['_cls']), set()).add(v['_ref'].id)
+                        reference_map.setdefault(get_document(v["_cls"]), set()).add(
+                            v["_ref"].id
+                        )
                     elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
-                        field_cls = getattr(getattr(field, 'field', None), 'document_type', None)
+                        field_cls = getattr(
+                            getattr(field, "field", None), "document_type", None
+                        )
                         references = self._find_references(v, depth)
-                        for key, refs in iteritems(references):
+                        for key, refs in references.items():
-                            if isinstance(field_cls, (Document, TopLevelDocumentMetaclass)):
+                            if isinstance(
+                                field_cls, (Document, TopLevelDocumentMetaclass)
+                            ):
                                 key = field_cls
                             reference_map.setdefault(key, set()).update(refs)
             elif isinstance(item, LazyReference):
@@ -134,11 +145,13 @@ class DeReference(object):
                 continue
             elif isinstance(item, DBRef):
                 reference_map.setdefault(item.collection, set()).add(item.id)
-            elif isinstance(item, (dict, SON)) and '_ref' in item:
+            elif isinstance(item, (dict, SON)) and "_ref" in item:
-                reference_map.setdefault(get_document(item['_cls']), set()).add(item['_ref'].id)
+                reference_map.setdefault(get_document(item["_cls"]), set()).add(
+                    item["_ref"].id
+                )
             elif isinstance(item, (dict, list, tuple)) and depth - 1 <= self.max_depth:
                 references = self._find_references(item, depth - 1)
-                for key, refs in iteritems(references):
+                for key, refs in references.items():
                     reference_map.setdefault(key, set()).update(refs)
 
         return reference_map
@@ -147,40 +160,44 @@ class DeReference(object):
         """Fetch all references and convert to their document objects
         """
         object_map = {}
-        for collection, dbrefs in iteritems(self.reference_map):
+        for collection, dbrefs in self.reference_map.items():
 
             # we use getattr instead of hasattr because hasattr swallows any exception under python2
             # so it could hide nasty things without raising exceptions (cfr bug #1688))
-            ref_document_cls_exists = (getattr(collection, 'objects', None) is not None)
+            ref_document_cls_exists = getattr(collection, "objects", None) is not None
 
             if ref_document_cls_exists:
                 col_name = collection._get_collection_name()
-                refs = [dbref for dbref in dbrefs
+                refs = [
-                        if (col_name, dbref) not in object_map]
+                    dbref for dbref in dbrefs if (col_name, dbref) not in object_map
+                ]
                 references = collection.objects.in_bulk(refs)
-                for key, doc in iteritems(references):
+                for key, doc in references.items():
                     object_map[(col_name, key)] = doc
             else:  # Generic reference: use the refs data to convert to document
                 if isinstance(doc_type, (ListField, DictField, MapField)):
                     continue
 
-                refs = [dbref for dbref in dbrefs
+                refs = [
-                        if (collection, dbref) not in object_map]
+                    dbref for dbref in dbrefs if (collection, dbref) not in object_map
+                ]
 
                 if doc_type:
-                    references = doc_type._get_db()[collection].find({'_id': {'$in': refs}})
+                    references = doc_type._get_db()[collection].find(
+                        {"_id": {"$in": refs}}
+                    )
                     for ref in references:
                         doc = doc_type._from_son(ref)
                         object_map[(collection, doc.id)] = doc
                 else:
-                    references = get_db()[collection].find({'_id': {'$in': refs}})
+                    references = get_db()[collection].find({"_id": {"$in": refs}})
                     for ref in references:
-                        if '_cls' in ref:
+                        if "_cls" in ref:
-                            doc = get_document(ref['_cls'])._from_son(ref)
+                            doc = get_document(ref["_cls"])._from_son(ref)
                         elif doc_type is None:
                             doc = get_document(
-                                ''.join(x.capitalize()
+                                "".join(x.capitalize() for x in collection.split("_"))
-                                        for x in collection.split('_')))._from_son(ref)
+                            )._from_son(ref)
                         else:
                             doc = doc_type._from_son(ref)
                         object_map[(collection, doc.id)] = doc
@@ -208,19 +225,20 @@ class DeReference(object):
                     return BaseList(items, instance, name)
 
         if isinstance(items, (dict, SON)):
-            if '_ref' in items:
+            if "_ref" in items:
                 return self.object_map.get(
-                    (items['_ref'].collection, items['_ref'].id), items)
+                    (items["_ref"].collection, items["_ref"].id), items
-            elif '_cls' in items:
+                )
-                doc = get_document(items['_cls'])._from_son(items)
+            elif "_cls" in items:
-                _cls = doc._data.pop('_cls', None)
+                doc = get_document(items["_cls"])._from_son(items)
-                del items['_cls']
+                _cls = doc._data.pop("_cls", None)
+                del items["_cls"]
                 doc._data = self._attach_objects(doc._data, depth, doc, None)
                 if _cls is not None:
-                    doc._data['_cls'] = _cls
+                    doc._data["_cls"] = _cls
                 return doc
 
-        if not hasattr(items, 'items'):
+        if not hasattr(items, "items"):
             is_list = True
             list_type = BaseList
             if isinstance(items, EmbeddedDocumentList):
@@ -230,7 +248,7 @@ class DeReference(object):
             data = []
         else:
             is_list = False
-            iterator = iteritems(items)
+            iterator = items.items()
             data = {}
 
         depth += 1
@@ -247,17 +265,23 @@ class DeReference(object):
                     v = data[k]._data.get(field_name, None)
                     if isinstance(v, DBRef):
                         data[k]._data[field_name] = self.object_map.get(
-                            (v.collection, v.id), v)
+                            (v.collection, v.id), v
-                    elif isinstance(v, (dict, SON)) and '_ref' in v:
+                        )
+                    elif isinstance(v, (dict, SON)) and "_ref" in v:
                         data[k]._data[field_name] = self.object_map.get(
-                            (v['_ref'].collection, v['_ref'].id), v)
+                            (v["_ref"].collection, v["_ref"].id), v
+                        )
                     elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
-                        item_name = six.text_type('{0}.{1}.{2}').format(name, k, field_name)
+                        item_name = "{}.{}.{}".format(name, k, field_name)
-                        data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=item_name)
+                        data[k]._data[field_name] = self._attach_objects(
+                            v, depth, instance=instance, name=item_name
+                        )
             elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
-                item_name = '%s.%s' % (name, k) if name else name
+                item_name = "{}.{}".format(name, k) if name else name
-                data[k] = self._attach_objects(v, depth - 1, instance=instance, name=item_name)
+                data[k] = self._attach_objects(
-            elif isinstance(v, DBRef) and hasattr(v, 'id'):
+                    v, depth - 1, instance=instance, name=item_name
+                )
+            elif isinstance(v, DBRef) and hasattr(v, "id"):
                 data[k] = self.object_map.get((v.collection, v.id), v)
 
         if instance and name:

mongoengine/document.py

@@ -4,46 +4,57 @@ import warnings
 from bson.dbref import DBRef
 import pymongo
 from pymongo.read_preferences import ReadPreference
-import six
-from six import iteritems
 
 from mongoengine import signals
-from mongoengine.base import (BaseDict, BaseDocument, BaseList,
+from mongoengine.base import (
-                              DocumentMetaclass, EmbeddedDocumentList,
+    BaseDict,
-                              TopLevelDocumentMetaclass, get_document)
+    BaseDocument,
+    BaseList,
+    DocumentMetaclass,
+    EmbeddedDocumentList,
+    TopLevelDocumentMetaclass,
+    get_document,
+)
 from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
-from mongoengine.context_managers import (set_write_concern,
+from mongoengine.context_managers import set_write_concern, switch_collection, switch_db
-                                          switch_collection,
+from mongoengine.errors import (
-                                          switch_db)
+    InvalidDocumentError,
-from mongoengine.errors import (InvalidDocumentError, InvalidQueryError,
+    InvalidQueryError,
-                                SaveConditionError)
+    SaveConditionError,
+)
 from mongoengine.pymongo_support import list_collection_names
-from mongoengine.queryset import (NotUniqueError, OperationError,
+from mongoengine.queryset import NotUniqueError, OperationError, QuerySet, transform
-                                  QuerySet, transform)
 
-__all__ = ('Document', 'EmbeddedDocument', 'DynamicDocument',
+__all__ = (
-           'DynamicEmbeddedDocument', 'OperationError',
+    "Document",
-           'InvalidCollectionError', 'NotUniqueError', 'MapReduceDocument')
+    "EmbeddedDocument",
+    "DynamicDocument",
+    "DynamicEmbeddedDocument",
+    "OperationError",
+    "InvalidCollectionError",
+    "NotUniqueError",
+    "MapReduceDocument",
+)
 
 
 def includes_cls(fields):
     """Helper function used for ensuring and comparing indexes."""
     first_field = None
     if len(fields):
-        if isinstance(fields[0], six.string_types):
+        if isinstance(fields[0], str):
             first_field = fields[0]
         elif isinstance(fields[0], (list, tuple)) and len(fields[0]):
             first_field = fields[0][0]
-    return first_field == '_cls'
+    return first_field == "_cls"
 
 
 class InvalidCollectionError(Exception):
     pass
 
 
-class EmbeddedDocument(six.with_metaclass(DocumentMetaclass, BaseDocument)):
+class EmbeddedDocument(BaseDocument, metaclass=DocumentMetaclass):
-    """A :class:`~mongoengine.Document` that isn't stored in its own
+    r"""A :class:`~mongoengine.Document` that isn't stored in its own
     collection.  :class:`~mongoengine.EmbeddedDocument`\ s should be used as
     fields on :class:`~mongoengine.Document`\ s through the
     :class:`~mongoengine.EmbeddedDocumentField` field type.
@@ -56,9 +67,8 @@ class EmbeddedDocument(six.with_metaclass(DocumentMetaclass, BaseDocument)):
     :attr:`meta` dictionary.
     """
 
-    __slots__ = ('_instance', )
+    __slots__ = ("_instance",)
 
-    # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = DocumentMetaclass
 
@@ -69,7 +79,7 @@ class EmbeddedDocument(six.with_metaclass(DocumentMetaclass, BaseDocument)):
     __hash__ = None
 
     def __init__(self, *args, **kwargs):
-        super(EmbeddedDocument, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
         self._instance = None
         self._changed_fields = []
 
@@ -82,16 +92,16 @@ class EmbeddedDocument(six.with_metaclass(DocumentMetaclass, BaseDocument)):
         return not self.__eq__(other)
 
     def to_mongo(self, *args, **kwargs):
-        data = super(EmbeddedDocument, self).to_mongo(*args, **kwargs)
+        data = super().to_mongo(*args, **kwargs)
 
         # remove _id from the SON if it's in it and it's None
-        if '_id' in data and data['_id'] is None:
+        if "_id" in data and data["_id"] is None:
-            del data['_id']
+            del data["_id"]
 
         return data
 
 
-class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
+class Document(BaseDocument, metaclass=TopLevelDocumentMetaclass):
     """The base class used for defining the structure and properties of
     collections of documents stored in MongoDB. Inherit from this class, and
     add fields as class attributes to define a document's structure.
@@ -143,23 +153,22 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
     in the :attr:`meta` dictionary.
     """
 
-    # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = TopLevelDocumentMetaclass
 
-    __slots__ = ('__objects',)
+    __slots__ = ("__objects",)
 
     @property
     def pk(self):
         """Get the primary key."""
-        if 'id_field' not in self._meta:
+        if "id_field" not in self._meta:
             return None
-        return getattr(self, self._meta['id_field'])
+        return getattr(self, self._meta["id_field"])
 
     @pk.setter
     def pk(self, value):
         """Set the primary key."""
-        return setattr(self, self._meta['id_field'], value)
+        return setattr(self, self._meta["id_field"], value)
 
     def __hash__(self):
         """Return the hash based on the PK of this document. If it's new
@@ -173,7 +182,7 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
     @classmethod
     def _get_db(cls):
         """Some Model using other db_alias"""
-        return get_db(cls._meta.get('db_alias', DEFAULT_CONNECTION_NAME))
+        return get_db(cls._meta.get("db_alias", DEFAULT_CONNECTION_NAME))
 
     @classmethod
     def _disconnect(cls):
@@ -190,9 +199,9 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         2. Creates indexes defined in this document's :attr:`meta` dictionary.
            This happens only if `auto_create_index` is True.
         """
-        if not hasattr(cls, '_collection') or cls._collection is None:
+        if not hasattr(cls, "_collection") or cls._collection is None:
             # Get the collection, either capped or regular.
-            if cls._meta.get('max_size') or cls._meta.get('max_documents'):
+            if cls._meta.get("max_size") or cls._meta.get("max_documents"):
                 cls._collection = cls._get_capped_collection()
             else:
                 db = cls._get_db()
@@ -203,8 +212,7 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
             # set to False.
             # Also there is no need to ensure indexes on slave.
             db = cls._get_db()
-            if cls._meta.get('auto_create_index', True) and\
+            if cls._meta.get("auto_create_index", True) and db.client.is_primary:
-                    db.client.is_primary:
                 cls.ensure_indexes()
 
         return cls._collection
@@ -216,8 +224,8 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         collection_name = cls._get_collection_name()
 
         # Get max document limit and max byte size from meta.
-        max_size = cls._meta.get('max_size') or 10 * 2 ** 20  # 10MB default
+        max_size = cls._meta.get("max_size") or 10 * 2 ** 20  # 10MB default
-        max_documents = cls._meta.get('max_documents')
+        max_documents = cls._meta.get("max_documents")
 
         # MongoDB will automatically raise the size to make it a multiple of
         # 256 bytes. We raise it here ourselves to be able to reliably compare
@@ -227,37 +235,36 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
         # If the collection already exists and has different options
         # (i.e. isn't capped or has different max/size), raise an error.
-        if collection_name in list_collection_names(db, include_system_collections=True):
+        if collection_name in list_collection_names(
+            db, include_system_collections=True
+        ):
             collection = db[collection_name]
             options = collection.options()
-            if (
+            if options.get("max") != max_documents or options.get("size") != max_size:
-                options.get('max') != max_documents or
-                options.get('size') != max_size
-            ):
                 raise InvalidCollectionError(
                     'Cannot create collection "{}" as a capped '
-                    'collection as it already exists'.format(cls._collection)
+                    "collection as it already exists".format(cls._collection)
                 )
 
             return collection
 
         # Create a new capped collection.
-        opts = {'capped': True, 'size': max_size}
+        opts = {"capped": True, "size": max_size}
         if max_documents:
-            opts['max'] = max_documents
+            opts["max"] = max_documents
 
         return db.create_collection(collection_name, **opts)
 
     def to_mongo(self, *args, **kwargs):
-        data = super(Document, self).to_mongo(*args, **kwargs)
+        data = super().to_mongo(*args, **kwargs)
 
         # If '_id' is None, try and set it from self._data. If that
         # doesn't exist either, remove '_id' from the SON completely.
-        if data['_id'] is None:
+        if data["_id"] is None:
-            if self._data.get('id') is None:
+            if self._data.get("id") is None:
-                del data['_id']
+                del data["_id"]
             else:
-                data['_id'] = self._data['id']
+                data["_id"] = self._data["id"]
 
         return data
 
@@ -279,15 +286,17 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
             query = {}
 
         if self.pk is None:
-            raise InvalidDocumentError('The document does not have a primary key.')
+            raise InvalidDocumentError("The document does not have a primary key.")
 
-        id_field = self._meta['id_field']
+        id_field = self._meta["id_field"]
         query = query.copy() if isinstance(query, dict) else query.to_query(self)
 
         if id_field not in query:
             query[id_field] = self.pk
         elif query[id_field] != self.pk:
-            raise InvalidQueryError('Invalid document modify query: it must modify only this document.')
+            raise InvalidQueryError(
+                "Invalid document modify query: it must modify only this document."
+            )
 
         # Need to add shard key to query, or you get an error
         query.update(self._object_key)
@@ -304,12 +313,22 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
         return True
 
-    def save(self, force_insert=False, validate=True, clean=True,
+    def save(
-             write_concern=None, cascade=None, cascade_kwargs=None,
+        self,
-             _refs=None, save_condition=None, signal_kwargs=None, **kwargs):
+        force_insert=False,
+        validate=True,
+        clean=True,
+        write_concern=None,
+        cascade=None,
+        cascade_kwargs=None,
+        _refs=None,
+        save_condition=None,
+        signal_kwargs=None,
+        **kwargs
+    ):
         """Save the :class:`~mongoengine.Document` to the database. If the
         document already exists, it will be updated, otherwise it will be
-        created.
+        created. Returns the saved object instance.
 
         :param force_insert: only try to create a new document, don't allow
             updates of existing documents.
@@ -360,8 +379,8 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         """
         signal_kwargs = signal_kwargs or {}
 
-        if self._meta.get('abstract'):
+        if self._meta.get("abstract"):
-            raise InvalidDocumentError('Cannot save an abstract document.')
+            raise InvalidDocumentError("Cannot save an abstract document.")
 
         signals.pre_save.send(self.__class__, document=self, **signal_kwargs)
 
@@ -371,15 +390,16 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         if write_concern is None:
             write_concern = {}
 
-        doc_id = self.to_mongo(fields=[self._meta['id_field']])
+        doc_id = self.to_mongo(fields=[self._meta["id_field"]])
-        created = ('_id' not in doc_id or self._created or force_insert)
+        created = "_id" not in doc_id or self._created or force_insert
 
-        signals.pre_save_post_validation.send(self.__class__, document=self,
+        signals.pre_save_post_validation.send(
-                                              created=created, **signal_kwargs)
+            self.__class__, document=self, created=created, **signal_kwargs
+        )
         # it might be refreshed by the pre_save_post_validation hook, e.g., for etag generation
         doc = self.to_mongo()
 
-        if self._meta.get('auto_create_index', True):
+        if self._meta.get("auto_create_index", True):
             self.ensure_indexes()
 
         try:
@@ -387,44 +407,45 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
             if created:
                 object_id = self._save_create(doc, force_insert, write_concern)
             else:
-                object_id, created = self._save_update(doc, save_condition,
+                object_id, created = self._save_update(
-                                                       write_concern)
+                    doc, save_condition, write_concern
+                )
 
             if cascade is None:
-                cascade = (self._meta.get('cascade', False) or
+                cascade = self._meta.get("cascade", False) or cascade_kwargs is not None
-                           cascade_kwargs is not None)
 
             if cascade:
                 kwargs = {
-                    'force_insert': force_insert,
+                    "force_insert": force_insert,
-                    'validate': validate,
+                    "validate": validate,
-                    'write_concern': write_concern,
+                    "write_concern": write_concern,
-                    'cascade': cascade
+                    "cascade": cascade,
                 }
                 if cascade_kwargs:  # Allow granular control over cascades
                     kwargs.update(cascade_kwargs)
-                kwargs['_refs'] = _refs
+                kwargs["_refs"] = _refs
                 self.cascade_save(**kwargs)
 
         except pymongo.errors.DuplicateKeyError as err:
-            message = u'Tried to save duplicate unique keys (%s)'
+            message = "Tried to save duplicate unique keys (%s)"
-            raise NotUniqueError(message % six.text_type(err))
+            raise NotUniqueError(message % err)
         except pymongo.errors.OperationFailure as err:
-            message = 'Could not save document (%s)'
+            message = "Could not save document (%s)"
-            if re.match('^E1100[01] duplicate key', six.text_type(err)):
+            if re.match("^E1100[01] duplicate key", str(err)):
                 # E11000 - duplicate key error index
                 # E11001 - duplicate key on update
-                message = u'Tried to save duplicate unique keys (%s)'
+                message = "Tried to save duplicate unique keys (%s)"
-                raise NotUniqueError(message % six.text_type(err))
+                raise NotUniqueError(message % err)
-            raise OperationError(message % six.text_type(err))
+            raise OperationError(message % err)
 
         # Make sure we store the PK on this document now that it's saved
-        id_field = self._meta['id_field']
+        id_field = self._meta["id_field"]
-        if created or id_field not in self._meta.get('shard_key', []):
+        if created or id_field not in self._meta.get("shard_key", []):
             self[id_field] = self._fields[id_field].to_python(object_id)
 
-        signals.post_save.send(self.__class__, document=self,
+        signals.post_save.send(
-                               created=created, **signal_kwargs)
+            self.__class__, document=self, created=created, **signal_kwargs
+        )
 
         self._clear_changed_fields()
         self._created = False
@@ -442,11 +463,12 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
                 return wc_collection.insert_one(doc).inserted_id
             # insert_one will provoke UniqueError alongside save does not
             # therefore, it need to catch and call replace_one.
-            if '_id' in doc:
+            if "_id" in doc:
                 raw_object = wc_collection.find_one_and_replace(
-                    {'_id': doc['_id']}, doc)
+                    {"_id": doc["_id"]}, doc
+                )
                 if raw_object:
-                    return doc['_id']
+                    return doc["_id"]
 
             object_id = wc_collection.insert_one(doc).inserted_id
 
@@ -461,9 +483,9 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
         update_doc = {}
         if updates:
-            update_doc['$set'] = updates
+            update_doc["$set"] = updates
         if removals:
-            update_doc['$unset'] = removals
+            update_doc["$unset"] = removals
 
         return update_doc
 
@@ -473,39 +495,38 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         Helper method, should only be used inside save().
         """
         collection = self._get_collection()
-        object_id = doc['_id']
+        object_id = doc["_id"]
         created = False
 
         select_dict = {}
         if save_condition is not None:
             select_dict = transform.query(self.__class__, **save_condition)
 
-        select_dict['_id'] = object_id
+        select_dict["_id"] = object_id
 
         # Need to add shard key to query, or you get an error
-        shard_key = self._meta.get('shard_key', tuple())
+        shard_key = self._meta.get("shard_key", tuple())
         for k in shard_key:
-            path = self._lookup_field(k.split('.'))
+            path = self._lookup_field(k.split("."))
             actual_key = [p.db_field for p in path]
             val = doc
             for ak in actual_key:
                 val = val[ak]
-            select_dict['.'.join(actual_key)] = val
+            select_dict[".".join(actual_key)] = val
 
         update_doc = self._get_update_doc()
         if update_doc:
             upsert = save_condition is None
             with set_write_concern(collection, write_concern) as wc_collection:
                 last_error = wc_collection.update_one(
-                    select_dict,
+                    select_dict, update_doc, upsert=upsert
-                    update_doc,
-                    upsert=upsert
                 ).raw_result
-            if not upsert and last_error['n'] == 0:
+            if not upsert and last_error["n"] == 0:
-                raise SaveConditionError('Race condition preventing'
+                raise SaveConditionError(
-                                         ' document update detected')
+                    "Race condition preventing document update detected"
+                )
             if last_error is not None:
-                updated_existing = last_error.get('updatedExisting')
+                updated_existing = last_error.get("updatedExisting")
                 if updated_existing is False:
                     created = True
                     # !!! This is bad, means we accidentally created a new,
@@ -518,24 +539,23 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         """Recursively save any references and generic references on the
         document.
         """
-        _refs = kwargs.get('_refs') or []
+        _refs = kwargs.get("_refs") or []
 
-        ReferenceField = _import_class('ReferenceField')
+        ReferenceField = _import_class("ReferenceField")
-        GenericReferenceField = _import_class('GenericReferenceField')
+        GenericReferenceField = _import_class("GenericReferenceField")
 
         for name, cls in self._fields.items():
-            if not isinstance(cls, (ReferenceField,
+            if not isinstance(cls, (ReferenceField, GenericReferenceField)):
-                                    GenericReferenceField)):
                 continue
 
             ref = self._data.get(name)
             if not ref or isinstance(ref, DBRef):
                 continue
 
-            if not getattr(ref, '_changed_fields', True):
+            if not getattr(ref, "_changed_fields", True):
                 continue
 
-            ref_id = "%s,%s" % (ref.__class__.__name__, str(ref._data))
+            ref_id = "{},{}".format(ref.__class__.__name__, str(ref._data))
             if ref and ref_id not in _refs:
                 _refs.append(ref_id)
                 kwargs["_refs"] = _refs
@@ -544,27 +564,31 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
     @property
     def _qs(self):
-        """Return the queryset to use for updating / reloading / deletions."""
+        """Return the default queryset corresponding to this document."""
-        if not hasattr(self, '__objects'):
+        if not hasattr(self, "__objects"):
             self.__objects = QuerySet(self, self._get_collection())
         return self.__objects
 
     @property
     def _object_key(self):
-        """Get the query dict that can be used to fetch this object from
+        """Return a query dict that can be used to fetch this document.
-        the database. Most of the time it's a simple PK lookup, but in
+
-        case of a sharded collection with a compound shard key, it can
+        Most of the time the dict is a simple PK lookup, but in case of
-        contain a more complex query.
+        a sharded collection with a compound shard key, it can contain a more
+        complex query.
+
+        Note that the dict returned by this method uses MongoEngine field
+        names instead of PyMongo field names (e.g. "pk" instead of "_id",
+        "some__nested__field" instead of "some.nested.field", etc.).
         """
-        select_dict = {'pk': self.pk}
+        select_dict = {"pk": self.pk}
-        shard_key = self.__class__._meta.get('shard_key', tuple())
+        shard_key = self.__class__._meta.get("shard_key", tuple())
         for k in shard_key:
-            path = self._lookup_field(k.split('.'))
-            actual_key = [p.db_field for p in path]
             val = self
-            for ak in actual_key:
+            field_parts = k.split(".")
-                val = getattr(val, ak)
+            for part in field_parts:
-            select_dict['__'.join(actual_key)] = val
+                val = getattr(val, part)
+            select_dict["__".join(field_parts)] = val
         return select_dict
 
     def update(self, **kwargs):
@@ -575,14 +599,13 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         been saved.
         """
         if self.pk is None:
-            if kwargs.get('upsert', False):
+            if kwargs.get("upsert", False):
                 query = self.to_mongo()
-                if '_cls' in query:
+                if "_cls" in query:
-                    del query['_cls']
+                    del query["_cls"]
                 return self._qs.filter(**query).update_one(**kwargs)
             else:
-                raise OperationError(
+                raise OperationError("attempt to update a document not yet saved")
-                    'attempt to update a document not yet saved')
 
         # Need to add shard key to query, or you get an error
         return self._qs.filter(**self._object_key).update_one(**kwargs)
@@ -606,16 +629,17 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         signals.pre_delete.send(self.__class__, document=self, **signal_kwargs)
 
         # Delete FileFields separately
-        FileField = _import_class('FileField')
+        FileField = _import_class("FileField")
-        for name, field in iteritems(self._fields):
+        for name, field in self._fields.items():
             if isinstance(field, FileField):
                 getattr(self, name).delete()
 
         try:
-            self._qs.filter(
+            self._qs.filter(**self._object_key).delete(
-                **self._object_key).delete(write_concern=write_concern, _from_doc_delete=True)
+                write_concern=write_concern, _from_doc_delete=True
+            )
         except pymongo.errors.OperationFailure as err:
-            message = u'Could not delete document (%s)' % err.message
+            message = "Could not delete document (%s)" % err.args
             raise OperationError(message)
         signals.post_delete.send(self.__class__, document=self, **signal_kwargs)
 
@@ -684,7 +708,7 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
         .. versionadded:: 0.5
         """
-        DeReference = _import_class('DeReference')
+        DeReference = _import_class("DeReference")
         DeReference()([self], max_depth + 1)
         return self
 
@@ -702,20 +726,24 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         if fields and isinstance(fields[0], int):
             max_depth = fields[0]
             fields = fields[1:]
-        elif 'max_depth' in kwargs:
+        elif "max_depth" in kwargs:
-            max_depth = kwargs['max_depth']
+            max_depth = kwargs["max_depth"]
 
         if self.pk is None:
-            raise self.DoesNotExist('Document does not exist')
+            raise self.DoesNotExist("Document does not exist")
 
-        obj = self._qs.read_preference(ReadPreference.PRIMARY).filter(
+        obj = (
-            **self._object_key).only(*fields).limit(
+            self._qs.read_preference(ReadPreference.PRIMARY)
-            1).select_related(max_depth=max_depth)
+            .filter(**self._object_key)
+            .only(*fields)
+            .limit(1)
+            .select_related(max_depth=max_depth)
+        )
 
         if obj:
             obj = obj[0]
         else:
-            raise self.DoesNotExist('Document does not exist')
+            raise self.DoesNotExist("Document does not exist")
         for field in obj._data:
             if not fields or field in fields:
                 try:
@@ -731,9 +759,11 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
                         # i.e. obj.update(unset__field=1) followed by obj.reload()
                         delattr(self, field)
 
-        self._changed_fields = list(
+        self._changed_fields = (
-            set(self._changed_fields) - set(fields)
+            list(set(self._changed_fields) - set(fields))
-        ) if fields else obj._changed_fields
+            if fields
+            else obj._changed_fields
+        )
         self._created = False
         return self
 
@@ -759,7 +789,7 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         """Returns an instance of :class:`~bson.dbref.DBRef` useful in
         `__raw__` queries."""
         if self.pk is None:
-            msg = 'Only saved documents can have a valid dbref'
+            msg = "Only saved documents can have a valid dbref"
             raise OperationError(msg)
         return DBRef(self.__class__._get_collection_name(), self.pk)
 
@@ -768,18 +798,22 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         """This method registers the delete rules to apply when removing this
         object.
         """
-        classes = [get_document(class_name)
+        classes = [
-                   for class_name in cls._subclasses
+            get_document(class_name)
-                   if class_name != cls.__name__] + [cls]
+            for class_name in cls._subclasses
-        documents = [get_document(class_name)
+            if class_name != cls.__name__
-                     for class_name in document_cls._subclasses
+        ] + [cls]
-                     if class_name != document_cls.__name__] + [document_cls]
+        documents = [
+            get_document(class_name)
+            for class_name in document_cls._subclasses
+            if class_name != document_cls.__name__
+        ] + [document_cls]
 
         for klass in classes:
             for document_cls in documents:
-                delete_rules = klass._meta.get('delete_rules') or {}
+                delete_rules = klass._meta.get("delete_rules") or {}
                 delete_rules[(document_cls, field_name)] = rule
-                klass._meta['delete_rules'] = delete_rules
+                klass._meta["delete_rules"] = delete_rules
 
     @classmethod
     def drop_collection(cls):
@@ -794,8 +828,9 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         """
         coll_name = cls._get_collection_name()
         if not coll_name:
-            raise OperationError('Document %s has no collection defined '
+            raise OperationError(
-                                 '(is it abstract ?)' % cls)
+                "Document %s has no collection defined (is it abstract ?)" % cls
+            )
         cls._collection = None
         db = cls._get_db()
         db.drop_collection(coll_name)
@@ -811,19 +846,14 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         """
         index_spec = cls._build_index_spec(keys)
         index_spec = index_spec.copy()
-        fields = index_spec.pop('fields')
+        fields = index_spec.pop("fields")
-        drop_dups = kwargs.get('drop_dups', False)
+        index_spec["background"] = background
-        if drop_dups:
-            msg = 'drop_dups is deprecated and is removed when using PyMongo 3+.'
-            warnings.warn(msg, DeprecationWarning)
-        index_spec['background'] = background
         index_spec.update(kwargs)
 
         return cls._get_collection().create_index(fields, **index_spec)
 
     @classmethod
-    def ensure_index(cls, key_or_list, drop_dups=False, background=False,
+    def ensure_index(cls, key_or_list, background=False, **kwargs):
-                     **kwargs):
         """Ensure that the given indexes are in place. Deprecated in favour
         of create_index.
 
@@ -831,12 +861,7 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
             construct a multi-field index); keys may be prefixed with a **+**
             or a **-** to determine the index ordering
         :param background: Allows index creation in the background
-        :param drop_dups: Was removed/ignored with MongoDB >2.7.5. The value
-            will be removed if PyMongo3+ is used
         """
-        if drop_dups:
-            msg = 'drop_dups is deprecated and is removed when using PyMongo 3+.'
-            warnings.warn(msg, DeprecationWarning)
         return cls.create_index(key_or_list, background=background, **kwargs)
 
     @classmethod
@@ -848,13 +873,9 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         .. note:: You can disable automatic index creation by setting
                   `auto_create_index` to False in the documents meta data
         """
-        background = cls._meta.get('index_background', False)
+        background = cls._meta.get("index_background", False)
-        drop_dups = cls._meta.get('index_drop_dups', False)
+        index_opts = cls._meta.get("index_opts") or {}
-        index_opts = cls._meta.get('index_opts') or {}
+        index_cls = cls._meta.get("index_cls", True)
-        index_cls = cls._meta.get('index_cls', True)
-        if drop_dups:
-            msg = 'drop_dups is deprecated and is removed when using PyMongo 3+.'
-            warnings.warn(msg, DeprecationWarning)
 
         collection = cls._get_collection()
         # 746: when connection is via mongos, the read preference is not necessarily an indication that
@@ -869,40 +890,39 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         cls_indexed = False
 
         # Ensure document-defined indexes are created
-        if cls._meta['index_specs']:
+        if cls._meta["index_specs"]:
-            index_spec = cls._meta['index_specs']
+            index_spec = cls._meta["index_specs"]
             for spec in index_spec:
                 spec = spec.copy()
-                fields = spec.pop('fields')
+                fields = spec.pop("fields")
                 cls_indexed = cls_indexed or includes_cls(fields)
                 opts = index_opts.copy()
                 opts.update(spec)
 
                 # we shouldn't pass 'cls' to the collection.ensureIndex options
                 # because of https://jira.mongodb.org/browse/SERVER-769
-                if 'cls' in opts:
+                if "cls" in opts:
-                    del opts['cls']
+                    del opts["cls"]
 
                 collection.create_index(fields, background=background, **opts)
 
         # If _cls is being used (for polymorphism), it needs an index,
         # only if another index doesn't begin with _cls
-        if index_cls and not cls_indexed and cls._meta.get('allow_inheritance'):
+        if index_cls and not cls_indexed and cls._meta.get("allow_inheritance"):
 
             # we shouldn't pass 'cls' to the collection.ensureIndex options
             # because of https://jira.mongodb.org/browse/SERVER-769
-            if 'cls' in index_opts:
+            if "cls" in index_opts:
-                del index_opts['cls']
+                del index_opts["cls"]
 
-            collection.create_index('_cls', background=background,
+            collection.create_index("_cls", background=background, **index_opts)
-                                    **index_opts)
 
     @classmethod
     def list_indexes(cls):
         """ Lists all of the indexes that should be created for given
         collection. It includes all the indexes from super- and sub-classes.
         """
-        if cls._meta.get('abstract'):
+        if cls._meta.get("abstract"):
             return []
 
         # get all the base classes, subclasses and siblings
@@ -910,22 +930,27 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
         def get_classes(cls):
 
-            if (cls not in classes and
+            if cls not in classes and isinstance(cls, TopLevelDocumentMetaclass):
-                    isinstance(cls, TopLevelDocumentMetaclass)):
                 classes.append(cls)
 
             for base_cls in cls.__bases__:
-                if (isinstance(base_cls, TopLevelDocumentMetaclass) and
+                if (
-                        base_cls != Document and
+                    isinstance(base_cls, TopLevelDocumentMetaclass)
-                        not base_cls._meta.get('abstract') and
+                    and base_cls != Document
-                        base_cls._get_collection().full_name == cls._get_collection().full_name and
+                    and not base_cls._meta.get("abstract")
-                        base_cls not in classes):
+                    and base_cls._get_collection().full_name
+                    == cls._get_collection().full_name
+                    and base_cls not in classes
+                ):
                     classes.append(base_cls)
                     get_classes(base_cls)
             for subclass in cls.__subclasses__():
-                if (isinstance(base_cls, TopLevelDocumentMetaclass) and
+                if (
-                        subclass._get_collection().full_name == cls._get_collection().full_name and
+                    isinstance(base_cls, TopLevelDocumentMetaclass)
-                        subclass not in classes):
+                    and subclass._get_collection().full_name
+                    == cls._get_collection().full_name
+                    and subclass not in classes
+                ):
                     classes.append(subclass)
                     get_classes(subclass)
 
@@ -935,11 +960,11 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         def get_indexes_spec(cls):
             indexes = []
 
-            if cls._meta['index_specs']:
+            if cls._meta["index_specs"]:
-                index_spec = cls._meta['index_specs']
+                index_spec = cls._meta["index_specs"]
                 for spec in index_spec:
                     spec = spec.copy()
-                    fields = spec.pop('fields')
+                    fields = spec.pop("fields")
                     indexes.append(fields)
             return indexes
 
@@ -950,10 +975,10 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
                     indexes.append(index)
 
         # finish up by appending { '_id': 1 } and { '_cls': 1 }, if needed
-        if [(u'_id', 1)] not in indexes:
+        if [("_id", 1)] not in indexes:
-            indexes.append([(u'_id', 1)])
+            indexes.append([("_id", 1)])
-        if cls._meta.get('index_cls', True) and cls._meta.get('allow_inheritance'):
+        if cls._meta.get("index_cls", True) and cls._meta.get("allow_inheritance"):
-            indexes.append([(u'_cls', 1)])
+            indexes.append([("_cls", 1)])
 
         return indexes
 
@@ -967,30 +992,29 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
 
         existing = []
         for info in cls._get_collection().index_information().values():
-            if '_fts' in info['key'][0]:
+            if "_fts" in info["key"][0]:
-                index_type = info['key'][0][1]
+                index_type = info["key"][0][1]
-                text_index_fields = info.get('weights').keys()
+                text_index_fields = info.get("weights").keys()
-                existing.append(
+                existing.append([(key, index_type) for key in text_index_fields])
-                    [(key, index_type) for key in text_index_fields])
             else:
-                existing.append(info['key'])
+                existing.append(info["key"])
         missing = [index for index in required if index not in existing]
         extra = [index for index in existing if index not in required]
 
         # if { _cls: 1 } is missing, make sure it's *really* necessary
-        if [(u'_cls', 1)] in missing:
+        if [("_cls", 1)] in missing:
             cls_obsolete = False
             for index in existing:
                 if includes_cls(index) and index not in extra:
                     cls_obsolete = True
                     break
             if cls_obsolete:
-                missing.remove([(u'_cls', 1)])
+                missing.remove([("_cls", 1)])
 
-        return {'missing': missing, 'extra': extra}
+        return {"missing": missing, "extra": extra}
 
 
-class DynamicDocument(six.with_metaclass(TopLevelDocumentMetaclass, Document)):
+class DynamicDocument(Document, metaclass=TopLevelDocumentMetaclass):
     """A Dynamic Document class allowing flexible, expandable and uncontrolled
     schemas.  As a :class:`~mongoengine.Document` subclass, acts in the same
     way as an ordinary document but has expanded style properties.  Any data
@@ -1004,7 +1028,6 @@ class DynamicDocument(six.with_metaclass(TopLevelDocumentMetaclass, Document)):
         There is one caveat on Dynamic Documents: undeclared fields cannot start with `_`
     """
 
-    # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = TopLevelDocumentMetaclass
 
@@ -1019,16 +1042,15 @@ class DynamicDocument(six.with_metaclass(TopLevelDocumentMetaclass, Document)):
             setattr(self, field_name, None)
             self._dynamic_fields[field_name].null = False
         else:
-            super(DynamicDocument, self).__delattr__(*args, **kwargs)
+            super().__delattr__(*args, **kwargs)
 
 
-class DynamicEmbeddedDocument(six.with_metaclass(DocumentMetaclass, EmbeddedDocument)):
+class DynamicEmbeddedDocument(EmbeddedDocument, metaclass=DocumentMetaclass):
     """A Dynamic Embedded Document class allowing flexible, expandable and
     uncontrolled schemas. See :class:`~mongoengine.DynamicDocument` for more
     information about dynamic documents.
     """
 
-    # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = DocumentMetaclass
 
@@ -1048,7 +1070,7 @@ class DynamicEmbeddedDocument(six.with_metaclass(DocumentMetaclass, EmbeddedDocu
             setattr(self, field_name, None)
 
 
-class MapReduceDocument(object):
+class MapReduceDocument:
     """A document returned from a map/reduce query.
 
     :param collection: An instance of :class:`~pymongo.Collection`
@@ -1072,17 +1094,16 @@ class MapReduceDocument(object):
         """Lazy-load the object referenced by ``self.key``. ``self.key``
         should be the ``primary_key``.
         """
-        id_field = self._document()._meta['id_field']
+        id_field = self._document()._meta["id_field"]
         id_field_type = type(id_field)
 
         if not isinstance(self.key, id_field_type):
             try:
                 self.key = id_field_type(self.key)
             except Exception:
-                raise Exception('Could not cast key as %s' %
+                raise Exception("Could not cast key as %s" % id_field_type.__name__)
-                                id_field_type.__name__)
 
-        if not hasattr(self, '_key_object'):
+        if not hasattr(self, "_key_object"):
             self._key_object = self._document.objects.with_id(self.key)
             return self._key_object
         return self._key_object

mongoengine/errors.py

@@ -1,12 +1,21 @@
 from collections import defaultdict
 
-import six
-from six import iteritems
 
-__all__ = ('NotRegistered', 'InvalidDocumentError', 'LookUpError',
+__all__ = (
-           'DoesNotExist', 'MultipleObjectsReturned', 'InvalidQueryError',
+    "NotRegistered",
-           'OperationError', 'NotUniqueError', 'FieldDoesNotExist',
+    "InvalidDocumentError",
-           'ValidationError', 'SaveConditionError', 'DeprecatedError')
+    "LookUpError",
+    "DoesNotExist",
+    "MultipleObjectsReturned",
+    "InvalidQueryError",
+    "OperationError",
+    "NotUniqueError",
+    "BulkWriteError",
+    "FieldDoesNotExist",
+    "ValidationError",
+    "SaveConditionError",
+    "DeprecatedError",
+)
 
 
 class NotRegistered(Exception):
@@ -41,6 +50,10 @@ class NotUniqueError(OperationError):
     pass
 
 
+class BulkWriteError(OperationError):
+    pass
+
+
 class SaveConditionError(OperationError):
     pass
 
@@ -71,25 +84,25 @@ class ValidationError(AssertionError):
     field_name = None
     _message = None
 
-    def __init__(self, message='', **kwargs):
+    def __init__(self, message="", **kwargs):
-        super(ValidationError, self).__init__(message)
+        super().__init__(message)
-        self.errors = kwargs.get('errors', {})
+        self.errors = kwargs.get("errors", {})
-        self.field_name = kwargs.get('field_name')
+        self.field_name = kwargs.get("field_name")
         self.message = message
 
     def __str__(self):
-        return six.text_type(self.message)
+        return str(self.message)
 
     def __repr__(self):
-        return '%s(%s,)' % (self.__class__.__name__, self.message)
+        return "{}({},)".format(self.__class__.__name__, self.message)
 
     def __getattribute__(self, name):
-        message = super(ValidationError, self).__getattribute__(name)
+        message = super().__getattribute__(name)
-        if name == 'message':
+        if name == "message":
             if self.field_name:
-                message = '%s' % message
+                message = "%s" % message
             if self.errors:
-                message = '%s(%s)' % (message, self._format_errors())
+                message = "{}({})".format(message, self._format_errors())
         return message
 
     def _get_message(self):
@@ -111,12 +124,12 @@ class ValidationError(AssertionError):
         def build_dict(source):
             errors_dict = {}
             if isinstance(source, dict):
-                for field_name, error in iteritems(source):
+                for field_name, error in source.items():
                     errors_dict[field_name] = build_dict(error)
             elif isinstance(source, ValidationError) and source.errors:
                 return build_dict(source.errors)
             else:
-                return six.text_type(source)
+                return str(source)
 
             return errors_dict
 
@@ -128,22 +141,22 @@ class ValidationError(AssertionError):
     def _format_errors(self):
         """Returns a string listing all errors within a document"""
 
-        def generate_key(value, prefix=''):
+        def generate_key(value, prefix=""):
             if isinstance(value, list):
-                value = ' '.join([generate_key(k) for k in value])
+                value = " ".join([generate_key(k) for k in value])
             elif isinstance(value, dict):
-                value = ' '.join(
+                value = " ".join([generate_key(v, k) for k, v in value.items()])
-                    [generate_key(v, k) for k, v in iteritems(value)])
 
-            results = '%s.%s' % (prefix, value) if prefix else value
+            results = "{}.{}".format(prefix, value) if prefix else value
             return results
 
         error_dict = defaultdict(list)
-        for k, v in iteritems(self.to_dict()):
+        for k, v in self.to_dict().items():
             error_dict[generate_key(v)].append(k)
-        return ' '.join(['%s: %s' % (k, v) for k, v in iteritems(error_dict)])
+        return " ".join(["{}: {}".format(k, v) for k, v in error_dict.items()])
 
 
 class DeprecatedError(Exception):
     """Raise when a user uses a feature that has been Deprecated"""
+
     pass

mongoengine/mongodb_support.py

@@ -11,9 +11,9 @@ MONGODB_36 = (3, 6)
 
 
 def get_mongodb_version():
-    """Return the version of the connected mongoDB (first 2 digits)
+    """Return the version of the default connected mongoDB (first 2 digits)
 
     :return: tuple(int, int)
     """
-    version_list = get_connection().server_info()['versionArray'][:2]     # e.g. (3, 2)
+    version_list = get_connection().server_info()["versionArray"][:2]  # e.g: (3, 2)
     return tuple(version_list)

mongoengine/pymongo_support.py

@@ -2,6 +2,7 @@
 Helper functions, constants, and types to aid with PyMongo v2.7 - v3.x support.
 """
 import pymongo
+from pymongo.errors import OperationFailure
 
 _PYMONGO_37 = (3, 7)
 
@@ -10,13 +11,41 @@ PYMONGO_VERSION = tuple(pymongo.version_tuple[:2])
 IS_PYMONGO_GTE_37 = PYMONGO_VERSION >= _PYMONGO_37
 
 
-def count_documents(collection, filter):
+def count_documents(
-    """Pymongo>3.7 deprecates count in favour of count_documents"""
+    collection, filter, skip=None, limit=None, hint=None, collation=None
+):
+    """Pymongo>3.7 deprecates count in favour of count_documents
+    """
+    if limit == 0:
+        return 0  # Pymongo raises an OperationFailure if called with limit=0
+
+    kwargs = {}
+    if skip is not None:
+        kwargs["skip"] = skip
+    if limit is not None:
+        kwargs["limit"] = limit
+    if hint not in (-1, None):
+        kwargs["hint"] = hint
+    if collation is not None:
+        kwargs["collation"] = collation
+
+    # count_documents appeared in pymongo 3.7
     if IS_PYMONGO_GTE_37:
-        return collection.count_documents(filter)
+        try:
-    else:
+            return collection.count_documents(filter=filter, **kwargs)
-        count = collection.find(filter).count()
+        except OperationFailure:
-    return count
+            # OperationFailure - accounts for some operators that used to work
+            # with .count but are no longer working with count_documents (i.e $geoNear, $near, and $nearSphere)
+            # fallback to deprecated Cursor.count
+            # Keeping this should be reevaluated the day pymongo removes .count entirely
+            pass
+
+    cursor = collection.find(filter)
+    for option, option_value in kwargs.items():
+        cursor_method = getattr(cursor, option)
+        cursor = cursor_method(option_value)
+    with_limit_and_skip = "skip" in kwargs or "limit" in kwargs
+    return cursor.count(with_limit_and_skip=with_limit_and_skip)
 
 
 def list_collection_names(db, include_system_collections=False):
@@ -27,6 +56,6 @@ def list_collection_names(db, include_system_collections=False):
         collections = db.collection_names()
 
     if not include_system_collections:
-        collections = [c for c in collections if not c.startswith('system.')]
+        collections = [c for c in collections if not c.startswith("system.")]
 
     return collections

mongoengine/python_support.py

@@ -1,23 +0,0 @@
-"""
-Helper functions, constants, and types to aid with Python v2.7 - v3.x support
-"""
-import six
-
-# six.BytesIO resolves to StringIO.StringIO in Py2 and io.BytesIO in Py3.
-StringIO = six.BytesIO
-
-# Additionally for Py2, try to use the faster cStringIO, if available
-if not six.PY3:
-    try:
-        import cStringIO
-    except ImportError:
-        pass
-    else:
-        StringIO = cStringIO.StringIO
-
-
-if six.PY3:
-    from collections.abc import Hashable
-else:
-    # raises DeprecationWarnings in Python >=3.7
-    from collections import Hashable

mongoengine/queryset/__init__.py

@@ -7,11 +7,22 @@ from mongoengine.queryset.visitor import *
 
 # Expose just the public subset of all imported objects and constants.
 __all__ = (
-    'QuerySet', 'QuerySetNoCache', 'Q', 'queryset_manager', 'QuerySetManager',
+    "QuerySet",
-    'QueryFieldList', 'DO_NOTHING', 'NULLIFY', 'CASCADE', 'DENY', 'PULL',
+    "QuerySetNoCache",
-
+    "Q",
+    "queryset_manager",
+    "QuerySetManager",
+    "QueryFieldList",
+    "DO_NOTHING",
+    "NULLIFY",
+    "CASCADE",
+    "DENY",
+    "PULL",
     # Errors that might be related to a queryset, mostly here for backward
     # compatibility
-    'DoesNotExist', 'InvalidQueryError', 'MultipleObjectsReturned',
+    "DoesNotExist",
-    'NotUniqueError', 'OperationError',
+    "InvalidQueryError",
+    "MultipleObjectsReturned",
+    "NotUniqueError",
+    "OperationError",
 )

mongoengine/queryset/field_list.py

@@ -1,12 +1,15 @@
-__all__ = ('QueryFieldList',)
+__all__ = ("QueryFieldList",)
 
 
-class QueryFieldList(object):
+class QueryFieldList:
     """Object that handles combinations of .only() and .exclude() calls"""
+
     ONLY = 1
     EXCLUDE = 0
 
-    def __init__(self, fields=None, value=ONLY, always_include=None, _only_called=False):
+    def __init__(
+        self, fields=None, value=ONLY, always_include=None, _only_called=False
+    ):
         """The QueryFieldList builder
 
         :param fields: A list of fields used in `.only()` or `.exclude()`
@@ -49,7 +52,7 @@ class QueryFieldList(object):
             self.fields = f.fields - self.fields
             self._clean_slice()
 
-        if '_id' in f.fields:
+        if "_id" in f.fields:
             self._id = f.value
 
         if self.always_include:
@@ -59,25 +62,23 @@ class QueryFieldList(object):
             else:
                 self.fields -= self.always_include
 
-        if getattr(f, '_only_called', False):
+        if getattr(f, "_only_called", False):
             self._only_called = True
         return self
 
     def __bool__(self):
         return bool(self.fields)
 
-    __nonzero__ = __bool__  # For Py2 support
-
     def as_dict(self):
         field_list = {field: self.value for field in self.fields}
         if self.slice:
             field_list.update(self.slice)
         if self._id is not None:
-            field_list['_id'] = self._id
+            field_list["_id"] = self._id
         return field_list
 
     def reset(self):
-        self.fields = set([])
+        self.fields = set()
         self.slice = {}
         self.value = self.ONLY
 

mongoengine/queryset/manager.py

@@ -1,10 +1,10 @@
 from functools import partial
 from mongoengine.queryset.queryset import QuerySet
 
-__all__ = ('queryset_manager', 'QuerySetManager')
+__all__ = ("queryset_manager", "QuerySetManager")
 
 
-class QuerySetManager(object):
+class QuerySetManager:
     """
     The default QuerySet Manager.
 
@@ -33,7 +33,7 @@ class QuerySetManager(object):
             return self
 
         # owner is the document that contains the QuerySetManager
-        queryset_class = owner._meta.get('queryset_class', self.default)
+        queryset_class = owner._meta.get("queryset_class", self.default)
         queryset = queryset_class(owner, owner._get_collection())
         if self.get_queryset:
             arg_count = self.get_queryset.__code__.co_argcount

mongoengine/queryset/queryset.py

@@ -1,11 +1,22 @@
-import six
-
 from mongoengine.errors import OperationError
-from mongoengine.queryset.base import (BaseQuerySet, CASCADE, DENY, DO_NOTHING,
+from mongoengine.queryset.base import (
-                                       NULLIFY, PULL)
+    BaseQuerySet,
+    CASCADE,
+    DENY,
+    DO_NOTHING,
+    NULLIFY,
+    PULL,
+)
 
-__all__ = ('QuerySet', 'QuerySetNoCache', 'DO_NOTHING', 'NULLIFY', 'CASCADE',
+__all__ = (
-           'DENY', 'PULL')
+    "QuerySet",
+    "QuerySetNoCache",
+    "DO_NOTHING",
+    "NULLIFY",
+    "CASCADE",
+    "DENY",
+    "PULL",
+)
 
 # The maximum number of items to display in a QuerySet.__repr__
 REPR_OUTPUT_SIZE = 20
@@ -57,12 +68,12 @@ class QuerySet(BaseQuerySet):
     def __repr__(self):
         """Provide a string representation of the QuerySet"""
         if self._iter:
-            return '.. queryset mid-iteration ..'
+            return ".. queryset mid-iteration .."
 
         self._populate_cache()
-        data = self._result_cache[:REPR_OUTPUT_SIZE + 1]
+        data = self._result_cache[: REPR_OUTPUT_SIZE + 1]
         if len(data) > REPR_OUTPUT_SIZE:
-            data[-1] = '...(remaining elements truncated)...'
+            data[-1] = "...(remaining elements truncated)..."
         return repr(data)
 
     def _iter_results(self):
@@ -114,8 +125,8 @@ class QuerySet(BaseQuerySet):
         # Pull in ITER_CHUNK_SIZE docs from the database and store them in
         # the result cache.
         try:
-            for _ in six.moves.range(ITER_CHUNK_SIZE):
+            for _ in range(ITER_CHUNK_SIZE):
-                self._result_cache.append(six.next(self))
+                self._result_cache.append(next(self))
         except StopIteration:
             # Getting this exception means there are no more docs in the
             # db cursor. Set _has_more to False so that we can use that
@@ -130,10 +141,11 @@ class QuerySet(BaseQuerySet):
             getting the count
         """
         if with_limit_and_skip is False:
-            return super(QuerySet, self).count(with_limit_and_skip)
+            return super().count(with_limit_and_skip)
 
         if self._len is None:
-            self._len = super(QuerySet, self).count(with_limit_and_skip)
+            # cache the length
+            self._len = super().count(with_limit_and_skip)
 
         return self._len
 
@@ -143,10 +155,9 @@ class QuerySet(BaseQuerySet):
         .. versionadded:: 0.8.3 Convert to non caching queryset
         """
         if self._result_cache is not None:
-            raise OperationError('QuerySet already cached')
+            raise OperationError("QuerySet already cached")
 
-        return self._clone_into(QuerySetNoCache(self._document,
+        return self._clone_into(QuerySetNoCache(self._document, self._collection))
-                                                self._collection))
 
 
 class QuerySetNoCache(BaseQuerySet):
@@ -165,17 +176,17 @@ class QuerySetNoCache(BaseQuerySet):
         .. versionchanged:: 0.6.13 Now doesnt modify the cursor
         """
         if self._iter:
-            return '.. queryset mid-iteration ..'
+            return ".. queryset mid-iteration .."
 
         data = []
-        for _ in six.moves.range(REPR_OUTPUT_SIZE + 1):
+        for _ in range(REPR_OUTPUT_SIZE + 1):
             try:
-                data.append(six.next(self))
+                data.append(next(self))
             except StopIteration:
                 break
 
         if len(data) > REPR_OUTPUT_SIZE:
-            data[-1] = '...(remaining elements truncated)...'
+            data[-1] = "...(remaining elements truncated)..."
 
         self.rewind()
         return repr(data)

mongoengine/queryset/transform.py

@@ -3,28 +3,59 @@ from collections import defaultdict
 from bson import ObjectId, SON
 from bson.dbref import DBRef
 import pymongo
-import six
-from six import iteritems
 
 from mongoengine.base import UPDATE_OPERATORS
 from mongoengine.common import _import_class
 from mongoengine.errors import InvalidQueryError
 
-__all__ = ('query', 'update')
+__all__ = ("query", "update", "STRING_OPERATORS")
 
-COMPARISON_OPERATORS = ('ne', 'gt', 'gte', 'lt', 'lte', 'in', 'nin', 'mod',
+COMPARISON_OPERATORS = (
-                        'all', 'size', 'exists', 'not', 'elemMatch', 'type')
+    "ne",
-GEO_OPERATORS = ('within_distance', 'within_spherical_distance',
+    "gt",
-                 'within_box', 'within_polygon', 'near', 'near_sphere',
+    "gte",
-                 'max_distance', 'min_distance', 'geo_within', 'geo_within_box',
+    "lt",
-                 'geo_within_polygon', 'geo_within_center',
+    "lte",
-                 'geo_within_sphere', 'geo_intersects')
+    "in",
-STRING_OPERATORS = ('contains', 'icontains', 'startswith',
+    "nin",
-                    'istartswith', 'endswith', 'iendswith',
+    "mod",
-                    'exact', 'iexact')
+    "all",
-CUSTOM_OPERATORS = ('match',)
+    "size",
-MATCH_OPERATORS = (COMPARISON_OPERATORS + GEO_OPERATORS +
+    "exists",
-                   STRING_OPERATORS + CUSTOM_OPERATORS)
+    "not",
+    "elemMatch",
+    "type",
+)
+GEO_OPERATORS = (
+    "within_distance",
+    "within_spherical_distance",
+    "within_box",
+    "within_polygon",
+    "near",
+    "near_sphere",
+    "max_distance",
+    "min_distance",
+    "geo_within",
+    "geo_within_box",
+    "geo_within_polygon",
+    "geo_within_center",
+    "geo_within_sphere",
+    "geo_intersects",
+)
+STRING_OPERATORS = (
+    "contains",
+    "icontains",
+    "startswith",
+    "istartswith",
+    "endswith",
+    "iendswith",
+    "exact",
+    "iexact",
+)
+CUSTOM_OPERATORS = ("match",)
+MATCH_OPERATORS = (
+    COMPARISON_OPERATORS + GEO_OPERATORS + STRING_OPERATORS + CUSTOM_OPERATORS
+)
 
 
 # TODO make this less complex
@@ -33,11 +64,11 @@ def query(_doc_cls=None, **kwargs):
     mongo_query = {}
     merge_query = defaultdict(list)
     for key, value in sorted(kwargs.items()):
-        if key == '__raw__':
+        if key == "__raw__":
             mongo_query.update(value)
             continue
 
-        parts = key.rsplit('__')
+        parts = key.rsplit("__")
         indices = [(i, p) for i, p in enumerate(parts) if p.isdigit()]
         parts = [part for part in parts if not part.isdigit()]
         # Check for an operator and transform to mongo-style if there is
@@ -46,11 +77,11 @@ def query(_doc_cls=None, **kwargs):
             op = parts.pop()
 
         # Allow to escape operator-like field name by __
-        if len(parts) > 1 and parts[-1] == '':
+        if len(parts) > 1 and parts[-1] == "":
             parts.pop()
 
         negate = False
-        if len(parts) > 1 and parts[-1] == 'not':
+        if len(parts) > 1 and parts[-1] == "not":
             parts.pop()
             negate = True
 
@@ -62,18 +93,18 @@ def query(_doc_cls=None, **kwargs):
                 raise InvalidQueryError(e)
             parts = []
 
-            CachedReferenceField = _import_class('CachedReferenceField')
+            CachedReferenceField = _import_class("CachedReferenceField")
-            GenericReferenceField = _import_class('GenericReferenceField')
+            GenericReferenceField = _import_class("GenericReferenceField")
 
             cleaned_fields = []
             for field in fields:
                 append_field = True
-                if isinstance(field, six.string_types):
+                if isinstance(field, str):
                     parts.append(field)
                     append_field = False
                 # is last and CachedReferenceField
                 elif isinstance(field, CachedReferenceField) and fields[-1] == field:
-                    parts.append('%s._id' % field.db_field)
+                    parts.append("%s._id" % field.db_field)
                 else:
                     parts.append(field.db_field)
 
@@ -83,15 +114,15 @@ def query(_doc_cls=None, **kwargs):
             # Convert value to proper value
             field = cleaned_fields[-1]
 
-            singular_ops = [None, 'ne', 'gt', 'gte', 'lt', 'lte', 'not']
+            singular_ops = [None, "ne", "gt", "gte", "lt", "lte", "not"]
             singular_ops += STRING_OPERATORS
             if op in singular_ops:
                 value = field.prepare_query_value(op, value)
 
                 if isinstance(field, CachedReferenceField) and value:
-                    value = value['_id']
+                    value = value["_id"]
 
-            elif op in ('in', 'nin', 'all', 'near') and not isinstance(value, dict):
+            elif op in ("in", "nin", "all", "near") and not isinstance(value, dict):
                 # Raise an error if the in/nin/all/near param is not iterable.
                 value = _prepare_query_for_iterable(field, op, value)
 
@@ -101,71 +132,77 @@ def query(_doc_cls=None, **kwargs):
             # * If the value is an ObjectId, the key should be "field_name._ref.$id".
             if isinstance(field, GenericReferenceField):
                 if isinstance(value, DBRef):
-                    parts[-1] += '._ref'
+                    parts[-1] += "._ref"
                 elif isinstance(value, ObjectId):
-                    parts[-1] += '._ref.$id'
+                    parts[-1] += "._ref.$id"
 
         # if op and op not in COMPARISON_OPERATORS:
         if op:
             if op in GEO_OPERATORS:
                 value = _geo_operator(field, op, value)
-            elif op in ('match', 'elemMatch'):
+            elif op in ("match", "elemMatch"):
-                ListField = _import_class('ListField')
+                ListField = _import_class("ListField")
-                EmbeddedDocumentField = _import_class('EmbeddedDocumentField')
+                EmbeddedDocumentField = _import_class("EmbeddedDocumentField")
                 if (
-                    isinstance(value, dict) and
+                    isinstance(value, dict)
-                    isinstance(field, ListField) and
+                    and isinstance(field, ListField)
-                    isinstance(field.field, EmbeddedDocumentField)
+                    and isinstance(field.field, EmbeddedDocumentField)
                 ):
                     value = query(field.field.document_type, **value)
                 else:
                     value = field.prepare_query_value(op, value)
-                value = {'$elemMatch': value}
+                value = {"$elemMatch": value}
             elif op in CUSTOM_OPERATORS:
-                NotImplementedError('Custom method "%s" has not '
+                NotImplementedError(
-                                    'been implemented' % op)
+                    'Custom method "%s" has not ' "been implemented" % op
+                )
             elif op not in STRING_OPERATORS:
-                value = {'$' + op: value}
+                value = {"$" + op: value}
 
         if negate:
-            value = {'$not': value}
+            value = {"$not": value}
 
         for i, part in indices:
             parts.insert(i, part)
 
-        key = '.'.join(parts)
+        key = ".".join(parts)
 
-        if op is None or key not in mongo_query:
+        if key not in mongo_query:
             mongo_query[key] = value
-        elif key in mongo_query:
+        else:
             if isinstance(mongo_query[key], dict) and isinstance(value, dict):
                 mongo_query[key].update(value)
                 # $max/minDistance needs to come last - convert to SON
                 value_dict = mongo_query[key]
-                if ('$maxDistance' in value_dict or '$minDistance' in value_dict) and \
+                if ("$maxDistance" in value_dict or "$minDistance" in value_dict) and (
-                        ('$near' in value_dict or '$nearSphere' in value_dict):
+                    "$near" in value_dict or "$nearSphere" in value_dict
+                ):
                     value_son = SON()
-                    for k, v in iteritems(value_dict):
+                    for k, v in value_dict.items():
-                        if k == '$maxDistance' or k == '$minDistance':
+                        if k == "$maxDistance" or k == "$minDistance":
                             continue
                         value_son[k] = v
                     # Required for MongoDB >= 2.6, may fail when combining
                     # PyMongo 3+ and MongoDB < 2.6
                     near_embedded = False
-                    for near_op in ('$near', '$nearSphere'):
+                    for near_op in ("$near", "$nearSphere"):
                         if isinstance(value_dict.get(near_op), dict):
                             value_son[near_op] = SON(value_son[near_op])
-                            if '$maxDistance' in value_dict:
+                            if "$maxDistance" in value_dict:
-                                value_son[near_op]['$maxDistance'] = value_dict['$maxDistance']
+                                value_son[near_op]["$maxDistance"] = value_dict[
-                            if '$minDistance' in value_dict:
+                                    "$maxDistance"
-                                value_son[near_op]['$minDistance'] = value_dict['$minDistance']
+                                ]
+                            if "$minDistance" in value_dict:
+                                value_son[near_op]["$minDistance"] = value_dict[
+                                    "$minDistance"
+                                ]
                             near_embedded = True
 
                     if not near_embedded:
-                        if '$maxDistance' in value_dict:
+                        if "$maxDistance" in value_dict:
-                            value_son['$maxDistance'] = value_dict['$maxDistance']
+                            value_son["$maxDistance"] = value_dict["$maxDistance"]
-                        if '$minDistance' in value_dict:
+                        if "$minDistance" in value_dict:
-                            value_son['$minDistance'] = value_dict['$minDistance']
+                            value_son["$minDistance"] = value_dict["$minDistance"]
                     mongo_query[key] = value_son
             else:
                 # Store for manually merging later
@@ -177,10 +214,10 @@ def query(_doc_cls=None, **kwargs):
         del mongo_query[k]
         if isinstance(v, list):
             value = [{k: val} for val in v]
-            if '$and' in mongo_query.keys():
+            if "$and" in mongo_query.keys():
-                mongo_query['$and'].extend(value)
+                mongo_query["$and"].extend(value)
             else:
-                mongo_query['$and'] = value
+                mongo_query["$and"] = value
 
     return mongo_query
 
@@ -192,15 +229,15 @@ def update(_doc_cls=None, **update):
     mongo_update = {}
 
     for key, value in update.items():
-        if key == '__raw__':
+        if key == "__raw__":
             mongo_update.update(value)
             continue
 
-        parts = key.split('__')
+        parts = key.split("__")
 
         # if there is no operator, default to 'set'
         if len(parts) < 3 and parts[0] not in UPDATE_OPERATORS:
-            parts.insert(0, 'set')
+            parts.insert(0, "set")
 
         # Check for an operator and transform to mongo-style if there is
         op = None
@@ -208,13 +245,13 @@ def update(_doc_cls=None, **update):
             op = parts.pop(0)
             # Convert Pythonic names to Mongo equivalents
             operator_map = {
-                'push_all': 'pushAll',
+                "push_all": "pushAll",
-                'pull_all': 'pullAll',
+                "pull_all": "pullAll",
-                'dec': 'inc',
+                "dec": "inc",
-                'add_to_set': 'addToSet',
+                "add_to_set": "addToSet",
-                'set_on_insert': 'setOnInsert'
+                "set_on_insert": "setOnInsert",
             }
-            if op == 'dec':
+            if op == "dec":
                 # Support decrement by flipping a positive value's sign
                 # and using 'inc'
                 value = -value
@@ -227,7 +264,7 @@ def update(_doc_cls=None, **update):
             match = parts.pop()
 
         # Allow to escape operator-like field name by __
-        if len(parts) > 1 and parts[-1] == '':
+        if len(parts) > 1 and parts[-1] == "":
             parts.pop()
 
         if _doc_cls:
@@ -242,10 +279,10 @@ def update(_doc_cls=None, **update):
             appended_sub_field = False
             for field in fields:
                 append_field = True
-                if isinstance(field, six.string_types):
+                if isinstance(field, str):
                     # Convert the S operator to $
-                    if field == 'S':
+                    if field == "S":
-                        field = '$'
+                        field = "$"
                     parts.append(field)
                     append_field = False
                 else:
@@ -253,7 +290,7 @@ def update(_doc_cls=None, **update):
                 if append_field:
                     appended_sub_field = False
                     cleaned_fields.append(field)
-                    if hasattr(field, 'field'):
+                    if hasattr(field, "field"):
                         cleaned_fields.append(field.field)
                         appended_sub_field = True
 
@@ -263,52 +300,53 @@ def update(_doc_cls=None, **update):
             else:
                 field = cleaned_fields[-1]
 
-            GeoJsonBaseField = _import_class('GeoJsonBaseField')
+            GeoJsonBaseField = _import_class("GeoJsonBaseField")
             if isinstance(field, GeoJsonBaseField):
                 value = field.to_mongo(value)
 
-            if op == 'pull':
+            if op == "pull":
                 if field.required or value is not None:
-                    if match in ('in', 'nin') and not isinstance(value, dict):
+                    if match in ("in", "nin") and not isinstance(value, dict):
                         value = _prepare_query_for_iterable(field, op, value)
                     else:
                         value = field.prepare_query_value(op, value)
-            elif op == 'push' and isinstance(value, (list, tuple, set)):
+            elif op == "push" and isinstance(value, (list, tuple, set)):
                 value = [field.prepare_query_value(op, v) for v in value]
-            elif op in (None, 'set', 'push'):
+            elif op in (None, "set", "push"):
                 if field.required or value is not None:
                     value = field.prepare_query_value(op, value)
-            elif op in ('pushAll', 'pullAll'):
+            elif op in ("pushAll", "pullAll"):
                 value = [field.prepare_query_value(op, v) for v in value]
-            elif op in ('addToSet', 'setOnInsert'):
+            elif op in ("addToSet", "setOnInsert"):
                 if isinstance(value, (list, tuple, set)):
                     value = [field.prepare_query_value(op, v) for v in value]
                 elif field.required or value is not None:
                     value = field.prepare_query_value(op, value)
-            elif op == 'unset':
+            elif op == "unset":
                 value = 1
-            elif op == 'inc':
+            elif op == "inc":
                 value = field.prepare_query_value(op, value)
 
         if match:
-            match = '$' + match
+            match = "$" + match
             value = {match: value}
 
-        key = '.'.join(parts)
+        key = ".".join(parts)
 
-        if 'pull' in op and '.' in key:
+        if "pull" in op and "." in key:
             # Dot operators don't work on pull operations
             # unless they point to a list field
             # Otherwise it uses nested dict syntax
-            if op == 'pullAll':
+            if op == "pullAll":
-                raise InvalidQueryError('pullAll operations only support '
+                raise InvalidQueryError(
-                                        'a single field depth')
+                    "pullAll operations only support a single field depth"
+                )
 
             # Look for the last list field and use dot notation until there
             field_classes = [c.__class__ for c in cleaned_fields]
             field_classes.reverse()
-            ListField = _import_class('ListField')
+            ListField = _import_class("ListField")
-            EmbeddedDocumentListField = _import_class('EmbeddedDocumentListField')
+            EmbeddedDocumentListField = _import_class("EmbeddedDocumentListField")
             if ListField in field_classes or EmbeddedDocumentListField in field_classes:
                 # Join all fields via dot notation to the last ListField or EmbeddedDocumentListField
                 # Then process as normal
@@ -317,37 +355,36 @@ def update(_doc_cls=None, **update):
                 else:
                     _check_field = EmbeddedDocumentListField
 
-                last_listField = len(
+                last_listField = len(cleaned_fields) - field_classes.index(_check_field)
-                    cleaned_fields) - field_classes.index(_check_field)
+                key = ".".join(parts[:last_listField])
-                key = '.'.join(parts[:last_listField])
                 parts = parts[last_listField:]
                 parts.insert(0, key)
 
             parts.reverse()
             for key in parts:
                 value = {key: value}
-        elif op == 'addToSet' and isinstance(value, list):
+        elif op == "addToSet" and isinstance(value, list):
-            value = {key: {'$each': value}}
+            value = {key: {"$each": value}}
-        elif op in ('push', 'pushAll'):
+        elif op in ("push", "pushAll"):
             if parts[-1].isdigit():
-                key = '.'.join(parts[0:-1])
+                key = ".".join(parts[0:-1])
                 position = int(parts[-1])
                 # $position expects an iterable. If pushing a single value,
                 # wrap it in a list.
                 if not isinstance(value, (set, tuple, list)):
                     value = [value]
-                value = {key: {'$each': value, '$position': position}}
+                value = {key: {"$each": value, "$position": position}}
             else:
-                if op == 'pushAll':
+                if op == "pushAll":
-                    op = 'push'  # convert to non-deprecated keyword
+                    op = "push"  # convert to non-deprecated keyword
                     if not isinstance(value, (set, tuple, list)):
                         value = [value]
-                    value = {key: {'$each': value}}
+                    value = {key: {"$each": value}}
                 else:
                     value = {key: value}
         else:
             value = {key: value}
-        key = '$' + op
+        key = "$" + op
         if key not in mongo_update:
             mongo_update[key] = value
         elif key in mongo_update and isinstance(mongo_update[key], dict):
@@ -358,45 +395,47 @@ def update(_doc_cls=None, **update):
 
 def _geo_operator(field, op, value):
     """Helper to return the query for a given geo query."""
-    if op == 'max_distance':
+    if op == "max_distance":
-        value = {'$maxDistance': value}
+        value = {"$maxDistance": value}
-    elif op == 'min_distance':
+    elif op == "min_distance":
-        value = {'$minDistance': value}
+        value = {"$minDistance": value}
     elif field._geo_index == pymongo.GEO2D:
-        if op == 'within_distance':
+        if op == "within_distance":
-            value = {'$within': {'$center': value}}
+            value = {"$within": {"$center": value}}
-        elif op == 'within_spherical_distance':
+        elif op == "within_spherical_distance":
-            value = {'$within': {'$centerSphere': value}}
+            value = {"$within": {"$centerSphere": value}}
-        elif op == 'within_polygon':
+        elif op == "within_polygon":
-            value = {'$within': {'$polygon': value}}
+            value = {"$within": {"$polygon": value}}
-        elif op == 'near':
+        elif op == "near":
-            value = {'$near': value}
+            value = {"$near": value}
-        elif op == 'near_sphere':
+        elif op == "near_sphere":
-            value = {'$nearSphere': value}
+            value = {"$nearSphere": value}
-        elif op == 'within_box':
+        elif op == "within_box":
-            value = {'$within': {'$box': value}}
+            value = {"$within": {"$box": value}}
-        else:
-            raise NotImplementedError('Geo method "%s" has not been '
-                                      'implemented for a GeoPointField' % op)
-    else:
-        if op == 'geo_within':
-            value = {'$geoWithin': _infer_geometry(value)}
-        elif op == 'geo_within_box':
-            value = {'$geoWithin': {'$box': value}}
-        elif op == 'geo_within_polygon':
-            value = {'$geoWithin': {'$polygon': value}}
-        elif op == 'geo_within_center':
-            value = {'$geoWithin': {'$center': value}}
-        elif op == 'geo_within_sphere':
-            value = {'$geoWithin': {'$centerSphere': value}}
-        elif op == 'geo_intersects':
-            value = {'$geoIntersects': _infer_geometry(value)}
-        elif op == 'near':
-            value = {'$near': _infer_geometry(value)}
         else:
             raise NotImplementedError(
-                'Geo method "%s" has not been implemented for a %s '
+                'Geo method "%s" has not been ' "implemented for a GeoPointField" % op
-                % (op, field._name)
+            )
+    else:
+        if op == "geo_within":
+            value = {"$geoWithin": _infer_geometry(value)}
+        elif op == "geo_within_box":
+            value = {"$geoWithin": {"$box": value}}
+        elif op == "geo_within_polygon":
+            value = {"$geoWithin": {"$polygon": value}}
+        elif op == "geo_within_center":
+            value = {"$geoWithin": {"$center": value}}
+        elif op == "geo_within_sphere":
+            value = {"$geoWithin": {"$centerSphere": value}}
+        elif op == "geo_intersects":
+            value = {"$geoIntersects": _infer_geometry(value)}
+        elif op == "near":
+            value = {"$near": _infer_geometry(value)}
+        else:
+            raise NotImplementedError(
+                'Geo method "{}" has not been implemented for a {} '.format(
+                    op, field._name
+                )
             )
     return value
 
@@ -406,51 +445,58 @@ def _infer_geometry(value):
     given value.
     """
     if isinstance(value, dict):
-        if '$geometry' in value:
+        if "$geometry" in value:
             return value
-        elif 'coordinates' in value and 'type' in value:
+        elif "coordinates" in value and "type" in value:
-            return {'$geometry': value}
+            return {"$geometry": value}
-        raise InvalidQueryError('Invalid $geometry dictionary should have '
+        raise InvalidQueryError(
-                                'type and coordinates keys')
+            "Invalid $geometry dictionary should have type and coordinates keys"
+        )
     elif isinstance(value, (list, set)):
         # TODO: shouldn't we test value[0][0][0][0] to see if it is MultiPolygon?
 
         try:
             value[0][0][0]
-            return {'$geometry': {'type': 'Polygon', 'coordinates': value}}
+            return {"$geometry": {"type": "Polygon", "coordinates": value}}
         except (TypeError, IndexError):
             pass
 
         try:
             value[0][0]
-            return {'$geometry': {'type': 'LineString', 'coordinates': value}}
+            return {"$geometry": {"type": "LineString", "coordinates": value}}
         except (TypeError, IndexError):
             pass
 
         try:
             value[0]
-            return {'$geometry': {'type': 'Point', 'coordinates': value}}
+            return {"$geometry": {"type": "Point", "coordinates": value}}
         except (TypeError, IndexError):
             pass
 
-    raise InvalidQueryError('Invalid $geometry data. Can be either a '
+    raise InvalidQueryError(
-                            'dictionary or (nested) lists of coordinate(s)')
+        "Invalid $geometry data. Can be either a "
+        "dictionary or (nested) lists of coordinate(s)"
+    )
 
 
 def _prepare_query_for_iterable(field, op, value):
     # We need a special check for BaseDocument, because - although it's iterable - using
     # it as such in the context of this method is most definitely a mistake.
-    BaseDocument = _import_class('BaseDocument')
+    BaseDocument = _import_class("BaseDocument")
 
     if isinstance(value, BaseDocument):
-        raise TypeError("When using the `in`, `nin`, `all`, or "
+        raise TypeError(
-                        "`near`-operators you can\'t use a "
+            "When using the `in`, `nin`, `all`, or "
-                        "`Document`, you must wrap your object "
+            "`near`-operators you can't use a "
-                        "in a list (object -> [object]).")
+            "`Document`, you must wrap your object "
+            "in a list (object -> [object])."
+        )
 
-    if not hasattr(value, '__iter__'):
+    if not hasattr(value, "__iter__"):
-        raise TypeError("The `in`, `nin`, `all`, or "
+        raise TypeError(
-                        "`near`-operators must be applied to an "
+            "The `in`, `nin`, `all`, or "
-                        "iterable (e.g. a list).")
+            "`near`-operators must be applied to an "
+            "iterable (e.g. a list)."
+        )
 
     return [field.prepare_query_value(op, v) for v in value]

mongoengine/queryset/visitor.py

@@ -1,12 +1,18 @@
 import copy
+import warnings
 
 from mongoengine.errors import InvalidQueryError
 from mongoengine.queryset import transform
 
-__all__ = ('Q', 'QNode')
+__all__ = ("Q", "QNode")
 
 
-class QNodeVisitor(object):
+def warn_empty_is_deprecated():
+    msg = "'empty' property is deprecated in favour of using 'not bool(filter)'"
+    warnings.warn(msg, DeprecationWarning, stacklevel=2)
+
+
+class QNodeVisitor:
     """Base visitor class for visiting Q-object nodes in a query tree.
     """
 
@@ -69,16 +75,16 @@ class QueryCompilerVisitor(QNodeVisitor):
         self.document = document
 
     def visit_combination(self, combination):
-        operator = '$and'
+        operator = "$and"
         if combination.operation == combination.OR:
-            operator = '$or'
+            operator = "$or"
         return {operator: combination.children}
 
     def visit_query(self, query):
         return transform.query(self.document, **query.query)
 
 
-class QNode(object):
+class QNode:
     """Base class for nodes in query trees."""
 
     AND = 0
@@ -96,16 +102,19 @@ class QNode(object):
         """Combine this node with another node into a QCombination
         object.
         """
-        if getattr(other, 'empty', True):
+        # If the other Q() is empty, ignore it and just use `self`.
+        if not bool(other):
             return self
 
-        if self.empty:
+        # Or if this Q is empty, ignore it and just use `other`.
+        if not bool(self):
             return other
 
         return QCombination(operation, [self, other])
 
     @property
     def empty(self):
+        warn_empty_is_deprecated()
         return False
 
     def __or__(self, other):
@@ -132,8 +141,11 @@ class QCombination(QNode):
                 self.children.append(node)
 
     def __repr__(self):
-        op = ' & ' if self.operation is self.AND else ' | '
+        op = " & " if self.operation is self.AND else " | "
-        return '(%s)' % op.join([repr(node) for node in self.children])
+        return "(%s)" % op.join([repr(node) for node in self.children])
+
+    def __bool__(self):
+        return bool(self.children)
 
     def accept(self, visitor):
         for i in range(len(self.children)):
@@ -144,8 +156,16 @@ class QCombination(QNode):
 
     @property
     def empty(self):
+        warn_empty_is_deprecated()
         return not bool(self.children)
 
+    def __eq__(self, other):
+        return (
+            self.__class__ == other.__class__
+            and self.operation == other.operation
+            and self.children == other.children
+        )
+
 
 class Q(QNode):
     """A simple query object, used in a query tree to build up more complex
@@ -156,11 +176,18 @@ class Q(QNode):
         self.query = query
 
     def __repr__(self):
-        return 'Q(**%s)' % repr(self.query)
+        return "Q(**%s)" % repr(self.query)
+
+    def __bool__(self):
+        return bool(self.query)
+
+    def __eq__(self, other):
+        return self.__class__ == other.__class__ and self.query == other.query
 
     def accept(self, visitor):
         return visitor.visit_query(self)
 
     @property
     def empty(self):
+        warn_empty_is_deprecated()
         return not bool(self.query)

mongoengine/signals.py

@@ -1,5 +1,12 @@
-__all__ = ('pre_init', 'post_init', 'pre_save', 'pre_save_post_validation',
+__all__ = (
-           'post_save', 'pre_delete', 'post_delete')
+    "pre_init",
+    "post_init",
+    "pre_save",
+    "pre_save_post_validation",
+    "post_save",
+    "pre_delete",
+    "post_delete",
+)
 
 signals_available = False
 try:
@@ -7,11 +14,12 @@ try:
 
     signals_available = True
 except ImportError:
-    class Namespace(object):
+
+    class Namespace:
         def signal(self, name, doc=None):
             return _FakeSignal(name, doc)
 
-    class _FakeSignal(object):
+    class _FakeSignal:
         """If blinker is unavailable, create a fake class with the same
         interface that allows sending of signals but will fail with an
         error on anything else.  Instead of doing anything on send, it
@@ -23,13 +31,16 @@ except ImportError:
             self.__doc__ = doc
 
         def _fail(self, *args, **kwargs):
-            raise RuntimeError('signalling support is unavailable '
+            raise RuntimeError(
-                               'because the blinker library is '
+                "signalling support is unavailable "
-                               'not installed.')
+                "because the blinker library is "
+                "not installed."
+            )
 
         send = lambda *a, **kw: None  # noqa
-        connect = disconnect = has_receivers_for = receivers_for = \
+        connect = (
-            temporarily_connected_to = _fail
+            disconnect
+        ) = has_receivers_for = receivers_for = temporarily_connected_to = _fail
         del _fail
 
 
@@ -37,12 +48,12 @@ except ImportError:
 # not put signals in here.  Create your own namespace instead.
 _signals = Namespace()
 
-pre_init = _signals.signal('pre_init')
+pre_init = _signals.signal("pre_init")
-post_init = _signals.signal('post_init')
+post_init = _signals.signal("post_init")
-pre_save = _signals.signal('pre_save')
+pre_save = _signals.signal("pre_save")
-pre_save_post_validation = _signals.signal('pre_save_post_validation')
+pre_save_post_validation = _signals.signal("pre_save_post_validation")
-post_save = _signals.signal('post_save')
+post_save = _signals.signal("post_save")
-pre_delete = _signals.signal('pre_delete')
+pre_delete = _signals.signal("pre_delete")
-post_delete = _signals.signal('post_delete')
+post_delete = _signals.signal("post_delete")
-pre_bulk_insert = _signals.signal('pre_bulk_insert')
+pre_bulk_insert = _signals.signal("pre_bulk_insert")
-post_bulk_insert = _signals.signal('post_bulk_insert')
+post_bulk_insert = _signals.signal("post_bulk_insert")

requirements-dev.txt

@@ -0,0 +1,8 @@
+black
+flake8
+flake8-import-order
+pre-commit
+pytest
+ipdb
+ipython
+tox

requirements.txt

@@ -1,7 +1,3 @@
-nose
 pymongo>=3.4
-six==1.10.0
-flake8
-flake8-import-order
 Sphinx==1.5.5
 sphinx-rtd-theme==0.2.4

setup.cfg

@@ -1,11 +1,10 @@
-[nosetests]
-verbosity=2
-detailed-errors=1
-#tests=tests
-cover-package=mongoengine
-
 [flake8]
-ignore=E501,F401,F403,F405,I201,I202,W504, W605
+ignore=E501,F401,F403,F405,I201,I202,W504, W605, W503
 exclude=build,dist,docs,venv,venv3,.tox,.eggs,tests
 max-complexity=47
 application-import-names=mongoengine,tests
+
+[tool:pytest]
+# Limits the discovery to tests directory
+# avoids that it runs for instance the benchmark
+testpaths = tests

setup.py

@@ -1,6 +1,9 @@
 import os
 import sys
+
+from pkg_resources import normalize_path
 from setuptools import find_packages, setup
+from setuptools.command.test import test as TestCommand
 
 # Hack to silence atexit traceback in newer python versions
 try:
@@ -8,13 +11,10 @@ try:
 except ImportError:
     pass
 
-DESCRIPTION = (
+DESCRIPTION = "MongoEngine is a Python Object-Document Mapper for working with MongoDB."
-    'MongoEngine is a Python Object-Document '
-    'Mapper for working with MongoDB.'
-)
 
 try:
-    with open('README.rst') as fin:
+    with open("README.rst") as fin:
         LONG_DESCRIPTION = fin.read()
 except Exception:
     LONG_DESCRIPTION = None
@@ -24,63 +24,124 @@ def get_version(version_tuple):
     """Return the version tuple as a string, e.g. for (0, 10, 7),
     return '0.10.7'.
     """
-    return '.'.join(map(str, version_tuple))
+    return ".".join(map(str, version_tuple))
+
+
+class PyTest(TestCommand):
+    """Will force pytest to search for tests inside the build directory
+    for 2to3 converted code (used by tox), instead of the current directory.
+    Required as long as we need 2to3
+
+    Known Limitation: https://tox.readthedocs.io/en/latest/example/pytest.html#known-issues-and-limitations
+    Source: https://www.hackzine.org/python-testing-with-pytest-and-2to3-plus-tox-and-travis-ci.html
+    """
+
+    # https://pytest.readthedocs.io/en/2.7.3/goodpractises.html#integration-with-setuptools-test-commands
+    # Allows to provide pytest command argument through the test runner command `python setup.py test`
+    # e.g: `python setup.py test -a "-k=test"`
+    # This only works for 1 argument though
+    user_options = [("pytest-args=", "a", "Arguments to pass to py.test")]
+
+    def initialize_options(self):
+        TestCommand.initialize_options(self)
+        self.pytest_args = ""
+
+    def finalize_options(self):
+        TestCommand.finalize_options(self)
+        self.test_args = ["tests"]
+        self.test_suite = True
+
+    def run_tests(self):
+        # import here, cause outside the eggs aren't loaded
+        from pkg_resources import _namespace_packages
+        import pytest
+
+        # Purge modules under test from sys.modules. The test loader will
+        # re-import them from the build location. Required when 2to3 is used
+        # with namespace packages.
+        if sys.version_info >= (3,) and getattr(self.distribution, "use_2to3", False):
+            module = self.test_args[-1].split(".")[0]
+            if module in _namespace_packages:
+                del_modules = []
+                if module in sys.modules:
+                    del_modules.append(module)
+                module += "."
+                for name in sys.modules:
+                    if name.startswith(module):
+                        del_modules.append(name)
+                map(sys.modules.__delitem__, del_modules)
+
+            # Run on the build directory for 2to3-built code
+            # This will prevent the old 2.x code from being found
+            # by py.test discovery mechanism, that apparently
+            # ignores sys.path..
+            ei_cmd = self.get_finalized_command("egg_info")
+            self.test_args = [normalize_path(ei_cmd.egg_base)]
+
+        cmd_args = self.test_args + ([self.pytest_args] if self.pytest_args else [])
+        errno = pytest.main(cmd_args)
+        sys.exit(errno)
 
 
 # Dirty hack to get version number from monogengine/__init__.py - we can't
 # import it as it depends on PyMongo and PyMongo isn't installed until this
 # file is read
-init = os.path.join(os.path.dirname(__file__), 'mongoengine', '__init__.py')
+init = os.path.join(os.path.dirname(__file__), "mongoengine", "__init__.py")
-version_line = list(filter(lambda l: l.startswith('VERSION'), open(init)))[0]
+version_line = list(filter(lambda l: l.startswith("VERSION"), open(init)))[0]
 
-VERSION = get_version(eval(version_line.split('=')[-1]))
+VERSION = get_version(eval(version_line.split("=")[-1]))
 
 CLASSIFIERS = [
-    'Development Status :: 4 - Beta',
+    "Development Status :: 5 - Production/Stable",
-    'Intended Audience :: Developers',
+    "Intended Audience :: Developers",
-    'License :: OSI Approved :: MIT License',
+    "License :: OSI Approved :: MIT License",
-    'Operating System :: OS Independent',
+    "Operating System :: OS Independent",
-    'Programming Language :: Python',
+    "Programming Language :: Python",
-    "Programming Language :: Python :: 2",
-    "Programming Language :: Python :: 2.7",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.5",
     "Programming Language :: Python :: 3.6",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
-    'Topic :: Database',
+    "Topic :: Database",
-    'Topic :: Software Development :: Libraries :: Python Modules',
+    "Topic :: Software Development :: Libraries :: Python Modules",
 ]
 
 extra_opts = {
-    'packages': find_packages(exclude=['tests', 'tests.*']),
+    "packages": find_packages(exclude=["tests", "tests.*"]),
-    'tests_require': ['nose', 'coverage==4.2', 'blinker', 'Pillow>=2.0.0']
+    "tests_require": [
+        "pytest<5.0",
+        "pytest-cov",
+        "coverage<5.0",  # recent coverage switched to sqlite format for the .coverage file which isn't handled properly by coveralls
+        "blinker",
+        "Pillow>=2.0.0, <7.0.0",  # 7.0.0 dropped Python2 support
+    ],
 }
-if sys.version_info[0] == 3:
+
-    extra_opts['use_2to3'] = True
+if "test" in sys.argv:
-    if 'test' in sys.argv or 'nosetests' in sys.argv:
+    extra_opts["packages"] = find_packages()
-        extra_opts['packages'] = find_packages()
+    extra_opts["package_data"] = {
-        extra_opts['package_data'] = {
+        "tests": ["fields/mongoengine.png", "fields/mongodb_leaf.png"]
-            'tests': ['fields/mongoengine.png', 'fields/mongodb_leaf.png']}
+    }
-else:
-    extra_opts['tests_require'] += ['python-dateutil']
 
 setup(
-    name='mongoengine',
+    name="mongoengine",
     version=VERSION,
-    author='Harry Marr',
+    author="Harry Marr",
-    author_email='harry.marr@gmail.com',
+    author_email="harry.marr@gmail.com",
     maintainer="Stefan Wojcik",
     maintainer_email="wojcikstefan@gmail.com",
-    url='http://mongoengine.org/',
+    url="http://mongoengine.org/",
-    download_url='https://github.com/MongoEngine/mongoengine/tarball/master',
+    download_url="https://github.com/MongoEngine/mongoengine/tarball/master",
-    license='MIT',
+    license="MIT",
     include_package_data=True,
     description=DESCRIPTION,
     long_description=LONG_DESCRIPTION,
-    platforms=['any'],
+    platforms=["any"],
     classifiers=CLASSIFIERS,
-    install_requires=['pymongo>=3.4', 'six'],
+    python_requires=">=3.5",
-    test_suite='nose.collector',
+    install_requires=["pymongo>=3.4, <4.0"],
+    cmdclass={"test": PyTest},
     **extra_opts
 )

tests/__init__.py

@@ -1,4 +0,0 @@
-from .all_warnings import AllWarnings
-from .document import *
-from .queryset import *
-from .fields import *

tests/all_warnings/__init__.py

@@ -1,42 +0,0 @@
-"""
-This test has been put into a module.  This is because it tests warnings that
-only get triggered on first hit.  This way we can ensure its imported into the
-top level and called first by the test suite.
-"""
-import unittest
-import warnings
-
-from mongoengine import *
-
-
-__all__ = ('AllWarnings', )
-
-
-class AllWarnings(unittest.TestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-        self.warning_list = []
-        self.showwarning_default = warnings.showwarning
-        warnings.showwarning = self.append_to_warning_list
-
-    def append_to_warning_list(self, message, category, *args):
-        self.warning_list.append({"message": message,
-                                  "category": category})
-
-    def tearDown(self):
-        # restore default handling of warnings
-        warnings.showwarning = self.showwarning_default
-
-    def test_document_collection_syntax_warning(self):
-
-        class NonAbstractBase(Document):
-            meta = {'allow_inheritance': True}
-
-        class InheritedDocumentFailTest(NonAbstractBase):
-            meta = {'collection': 'fail'}
-
-        warning = self.warning_list[0]
-        self.assertEqual(SyntaxWarning, warning["category"])
-        self.assertEqual('non_abstract_base',
-                         InheritedDocumentFailTest._get_collection_name())

tests/all_warnings/test_warnings.py

@@ -0,0 +1,35 @@
+"""
+This test has been put into a module.  This is because it tests warnings that
+only get triggered on first hit.  This way we can ensure its imported into the
+top level and called first by the test suite.
+"""
+import unittest
+import warnings
+
+from mongoengine import *
+
+
+class TestAllWarnings(unittest.TestCase):
+    def setUp(self):
+        connect(db="mongoenginetest")
+        self.warning_list = []
+        self.showwarning_default = warnings.showwarning
+        warnings.showwarning = self.append_to_warning_list
+
+    def append_to_warning_list(self, message, category, *args):
+        self.warning_list.append({"message": message, "category": category})
+
+    def tearDown(self):
+        # restore default handling of warnings
+        warnings.showwarning = self.showwarning_default
+
+    def test_document_collection_syntax_warning(self):
+        class NonAbstractBase(Document):
+            meta = {"allow_inheritance": True}
+
+        class InheritedDocumentFailTest(NonAbstractBase):
+            meta = {"collection": "fail"}
+
+        warning = self.warning_list[0]
+        assert SyntaxWarning == warning["category"]
+        assert "non_abstract_base" == InheritedDocumentFailTest._get_collection_name()

tests/document/__init__.py

@@ -1,13 +0,0 @@
-import unittest
-
-from .class_methods import *
-from .delta import *
-from .dynamic import *
-from .indexes import *
-from .inheritance import *
-from .instance import *
-from .json_serialisation import *
-from .validation import *
-
-if __name__ == '__main__':
-    unittest.main()

tests/document/delta.py

@@ -1,864 +0,0 @@
-# -*- coding: utf-8 -*-
-import unittest
-
-from bson import SON
-from mongoengine import *
-from mongoengine.pymongo_support import list_collection_names
-from tests.utils import MongoDBTestCase
-
-
-class DeltaTest(MongoDBTestCase):
-
-    def setUp(self):
-        super(DeltaTest, self).setUp()
-
-        class Person(Document):
-            name = StringField()
-            age = IntField()
-
-            non_field = True
-
-            meta = {"allow_inheritance": True}
-
-        self.Person = Person
-
-    def tearDown(self):
-        for collection in list_collection_names(self.db):
-            self.db.drop_collection(collection)
-
-    def test_delta(self):
-        self.delta(Document)
-        self.delta(DynamicDocument)
-
-    def delta(self, DocClass):
-
-        class Doc(DocClass):
-            string_field = StringField()
-            int_field = IntField()
-            dict_field = DictField()
-            list_field = ListField()
-
-        Doc.drop_collection()
-        doc = Doc()
-        doc.save()
-
-        doc = Doc.objects.first()
-        self.assertEqual(doc._get_changed_fields(), [])
-        self.assertEqual(doc._delta(), ({}, {}))
-
-        doc.string_field = 'hello'
-        self.assertEqual(doc._get_changed_fields(), ['string_field'])
-        self.assertEqual(doc._delta(), ({'string_field': 'hello'}, {}))
-
-        doc._changed_fields = []
-        doc.int_field = 1
-        self.assertEqual(doc._get_changed_fields(), ['int_field'])
-        self.assertEqual(doc._delta(), ({'int_field': 1}, {}))
-
-        doc._changed_fields = []
-        dict_value = {'hello': 'world', 'ping': 'pong'}
-        doc.dict_field = dict_value
-        self.assertEqual(doc._get_changed_fields(), ['dict_field'])
-        self.assertEqual(doc._delta(), ({'dict_field': dict_value}, {}))
-
-        doc._changed_fields = []
-        list_value = ['1', 2, {'hello': 'world'}]
-        doc.list_field = list_value
-        self.assertEqual(doc._get_changed_fields(), ['list_field'])
-        self.assertEqual(doc._delta(), ({'list_field': list_value}, {}))
-
-        # Test unsetting
-        doc._changed_fields = []
-        doc.dict_field = {}
-        self.assertEqual(doc._get_changed_fields(), ['dict_field'])
-        self.assertEqual(doc._delta(), ({}, {'dict_field': 1}))
-
-        doc._changed_fields = []
-        doc.list_field = []
-        self.assertEqual(doc._get_changed_fields(), ['list_field'])
-        self.assertEqual(doc._delta(), ({}, {'list_field': 1}))
-
-    def test_delta_recursive(self):
-        self.delta_recursive(Document, EmbeddedDocument)
-        self.delta_recursive(DynamicDocument, EmbeddedDocument)
-        self.delta_recursive(Document, DynamicEmbeddedDocument)
-        self.delta_recursive(DynamicDocument, DynamicEmbeddedDocument)
-
-    def delta_recursive(self, DocClass, EmbeddedClass):
-
-        class Embedded(EmbeddedClass):
-            id = StringField()
-            string_field = StringField()
-            int_field = IntField()
-            dict_field = DictField()
-            list_field = ListField()
-
-        class Doc(DocClass):
-            string_field = StringField()
-            int_field = IntField()
-            dict_field = DictField()
-            list_field = ListField()
-            embedded_field = EmbeddedDocumentField(Embedded)
-
-        Doc.drop_collection()
-        doc = Doc()
-        doc.save()
-
-        doc = Doc.objects.first()
-        self.assertEqual(doc._get_changed_fields(), [])
-        self.assertEqual(doc._delta(), ({}, {}))
-
-        embedded_1 = Embedded()
-        embedded_1.id = "010101"
-        embedded_1.string_field = 'hello'
-        embedded_1.int_field = 1
-        embedded_1.dict_field = {'hello': 'world'}
-        embedded_1.list_field = ['1', 2, {'hello': 'world'}]
-        doc.embedded_field = embedded_1
-
-        self.assertEqual(doc._get_changed_fields(), ['embedded_field'])
-
-        embedded_delta = {
-            'id': "010101",
-            'string_field': 'hello',
-            'int_field': 1,
-            'dict_field': {'hello': 'world'},
-            'list_field': ['1', 2, {'hello': 'world'}]
-        }
-        self.assertEqual(doc.embedded_field._delta(), (embedded_delta, {}))
-        self.assertEqual(doc._delta(),
-                         ({'embedded_field': embedded_delta}, {}))
-
-        doc.save()
-        doc = doc.reload(10)
-
-        doc.embedded_field.dict_field = {}
-        self.assertEqual(doc._get_changed_fields(),
-                         ['embedded_field.dict_field'])
-        self.assertEqual(doc.embedded_field._delta(), ({}, {'dict_field': 1}))
-        self.assertEqual(doc._delta(), ({}, {'embedded_field.dict_field': 1}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.dict_field, {})
-
-        doc.embedded_field.list_field = []
-        self.assertEqual(doc._get_changed_fields(),
-                         ['embedded_field.list_field'])
-        self.assertEqual(doc.embedded_field._delta(), ({}, {'list_field': 1}))
-        self.assertEqual(doc._delta(), ({}, {'embedded_field.list_field': 1}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field, [])
-
-        embedded_2 = Embedded()
-        embedded_2.string_field = 'hello'
-        embedded_2.int_field = 1
-        embedded_2.dict_field = {'hello': 'world'}
-        embedded_2.list_field = ['1', 2, {'hello': 'world'}]
-
-        doc.embedded_field.list_field = ['1', 2, embedded_2]
-        self.assertEqual(doc._get_changed_fields(),
-                         ['embedded_field.list_field'])
-
-        self.assertEqual(doc.embedded_field._delta(), ({
-            'list_field': ['1', 2, {
-                '_cls': 'Embedded',
-                'string_field': 'hello',
-                'dict_field': {'hello': 'world'},
-                'int_field': 1,
-                'list_field': ['1', 2, {'hello': 'world'}],
-            }]
-        }, {}))
-
-        self.assertEqual(doc._delta(), ({
-            'embedded_field.list_field': ['1', 2, {
-                '_cls': 'Embedded',
-                'string_field': 'hello',
-                'dict_field': {'hello': 'world'},
-                'int_field': 1,
-                'list_field': ['1', 2, {'hello': 'world'}],
-            }]
-        }, {}))
-        doc.save()
-        doc = doc.reload(10)
-
-        self.assertEqual(doc.embedded_field.list_field[0], '1')
-        self.assertEqual(doc.embedded_field.list_field[1], 2)
-        for k in doc.embedded_field.list_field[2]._fields:
-            self.assertEqual(doc.embedded_field.list_field[2][k],
-                             embedded_2[k])
-
-        doc.embedded_field.list_field[2].string_field = 'world'
-        self.assertEqual(doc._get_changed_fields(),
-                         ['embedded_field.list_field.2.string_field'])
-        self.assertEqual(doc.embedded_field._delta(),
-                         ({'list_field.2.string_field': 'world'}, {}))
-        self.assertEqual(doc._delta(),
-                         ({'embedded_field.list_field.2.string_field': 'world'}, {}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].string_field,
-                         'world')
-
-        # Test multiple assignments
-        doc.embedded_field.list_field[2].string_field = 'hello world'
-        doc.embedded_field.list_field[2] = doc.embedded_field.list_field[2]
-        self.assertEqual(doc._get_changed_fields(),
-                         ['embedded_field.list_field.2'])
-        self.assertEqual(doc.embedded_field._delta(), ({'list_field.2': {
-                '_cls': 'Embedded',
-                'string_field': 'hello world',
-                'int_field': 1,
-                'list_field': ['1', 2, {'hello': 'world'}],
-                'dict_field': {'hello': 'world'}}
-            }, {}))
-        self.assertEqual(doc._delta(), ({'embedded_field.list_field.2': {
-                '_cls': 'Embedded',
-                'string_field': 'hello world',
-                'int_field': 1,
-                'list_field': ['1', 2, {'hello': 'world'}],
-                'dict_field': {'hello': 'world'}}
-            }, {}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].string_field,
-                         'hello world')
-
-        # Test list native methods
-        doc.embedded_field.list_field[2].list_field.pop(0)
-        self.assertEqual(doc._delta(),
-                         ({'embedded_field.list_field.2.list_field':
-                          [2, {'hello': 'world'}]}, {}))
-        doc.save()
-        doc = doc.reload(10)
-
-        doc.embedded_field.list_field[2].list_field.append(1)
-        self.assertEqual(doc._delta(),
-                         ({'embedded_field.list_field.2.list_field':
-                          [2, {'hello': 'world'}, 1]}, {}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].list_field,
-                         [2, {'hello': 'world'}, 1])
-
-        doc.embedded_field.list_field[2].list_field.sort(key=str)
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].list_field,
-                         [1, 2, {'hello': 'world'}])
-
-        del doc.embedded_field.list_field[2].list_field[2]['hello']
-        self.assertEqual(doc._delta(),
-                         ({}, {'embedded_field.list_field.2.list_field.2.hello': 1}))
-        doc.save()
-        doc = doc.reload(10)
-
-        del doc.embedded_field.list_field[2].list_field
-        self.assertEqual(doc._delta(),
-                         ({}, {'embedded_field.list_field.2.list_field': 1}))
-
-        doc.save()
-        doc = doc.reload(10)
-
-        doc.dict_field['Embedded'] = embedded_1
-        doc.save()
-        doc = doc.reload(10)
-
-        doc.dict_field['Embedded'].string_field = 'Hello World'
-        self.assertEqual(doc._get_changed_fields(),
-                         ['dict_field.Embedded.string_field'])
-        self.assertEqual(doc._delta(),
-                         ({'dict_field.Embedded.string_field': 'Hello World'}, {}))
-
-    def test_circular_reference_deltas(self):
-        self.circular_reference_deltas(Document, Document)
-        self.circular_reference_deltas(Document, DynamicDocument)
-        self.circular_reference_deltas(DynamicDocument, Document)
-        self.circular_reference_deltas(DynamicDocument, DynamicDocument)
-
-    def circular_reference_deltas(self, DocClass1, DocClass2):
-
-        class Person(DocClass1):
-            name = StringField()
-            owns = ListField(ReferenceField('Organization'))
-
-        class Organization(DocClass2):
-            name = StringField()
-            owner = ReferenceField('Person')
-
-        Person.drop_collection()
-        Organization.drop_collection()
-
-        person = Person(name="owner").save()
-        organization = Organization(name="company").save()
-
-        person.owns.append(organization)
-        organization.owner = person
-
-        person.save()
-        organization.save()
-
-        p = Person.objects[0].select_related()
-        o = Organization.objects.first()
-        self.assertEqual(p.owns[0], o)
-        self.assertEqual(o.owner, p)
-
-    def test_circular_reference_deltas_2(self):
-        self.circular_reference_deltas_2(Document, Document)
-        self.circular_reference_deltas_2(Document, DynamicDocument)
-        self.circular_reference_deltas_2(DynamicDocument, Document)
-        self.circular_reference_deltas_2(DynamicDocument, DynamicDocument)
-
-    def circular_reference_deltas_2(self, DocClass1, DocClass2, dbref=True):
-
-        class Person(DocClass1):
-            name = StringField()
-            owns = ListField(ReferenceField('Organization', dbref=dbref))
-            employer = ReferenceField('Organization', dbref=dbref)
-
-        class Organization(DocClass2):
-            name = StringField()
-            owner = ReferenceField('Person', dbref=dbref)
-            employees = ListField(ReferenceField('Person', dbref=dbref))
-
-        Person.drop_collection()
-        Organization.drop_collection()
-
-        person = Person(name="owner").save()
-        employee = Person(name="employee").save()
-        organization = Organization(name="company").save()
-
-        person.owns.append(organization)
-        organization.owner = person
-
-        organization.employees.append(employee)
-        employee.employer = organization
-
-        person.save()
-        organization.save()
-        employee.save()
-
-        p = Person.objects.get(name="owner")
-        e = Person.objects.get(name="employee")
-        o = Organization.objects.first()
-
-        self.assertEqual(p.owns[0], o)
-        self.assertEqual(o.owner, p)
-        self.assertEqual(e.employer, o)
-
-        return person, organization, employee
-
-    def test_delta_db_field(self):
-        self.delta_db_field(Document)
-        self.delta_db_field(DynamicDocument)
-
-    def delta_db_field(self, DocClass):
-
-        class Doc(DocClass):
-            string_field = StringField(db_field='db_string_field')
-            int_field = IntField(db_field='db_int_field')
-            dict_field = DictField(db_field='db_dict_field')
-            list_field = ListField(db_field='db_list_field')
-
-        Doc.drop_collection()
-        doc = Doc()
-        doc.save()
-
-        doc = Doc.objects.first()
-        self.assertEqual(doc._get_changed_fields(), [])
-        self.assertEqual(doc._delta(), ({}, {}))
-
-        doc.string_field = 'hello'
-        self.assertEqual(doc._get_changed_fields(), ['db_string_field'])
-        self.assertEqual(doc._delta(), ({'db_string_field': 'hello'}, {}))
-
-        doc._changed_fields = []
-        doc.int_field = 1
-        self.assertEqual(doc._get_changed_fields(), ['db_int_field'])
-        self.assertEqual(doc._delta(), ({'db_int_field': 1}, {}))
-
-        doc._changed_fields = []
-        dict_value = {'hello': 'world', 'ping': 'pong'}
-        doc.dict_field = dict_value
-        self.assertEqual(doc._get_changed_fields(), ['db_dict_field'])
-        self.assertEqual(doc._delta(), ({'db_dict_field': dict_value}, {}))
-
-        doc._changed_fields = []
-        list_value = ['1', 2, {'hello': 'world'}]
-        doc.list_field = list_value
-        self.assertEqual(doc._get_changed_fields(), ['db_list_field'])
-        self.assertEqual(doc._delta(), ({'db_list_field': list_value}, {}))
-
-        # Test unsetting
-        doc._changed_fields = []
-        doc.dict_field = {}
-        self.assertEqual(doc._get_changed_fields(), ['db_dict_field'])
-        self.assertEqual(doc._delta(), ({}, {'db_dict_field': 1}))
-
-        doc._changed_fields = []
-        doc.list_field = []
-        self.assertEqual(doc._get_changed_fields(), ['db_list_field'])
-        self.assertEqual(doc._delta(), ({}, {'db_list_field': 1}))
-
-        # Test it saves that data
-        doc = Doc()
-        doc.save()
-
-        doc.string_field = 'hello'
-        doc.int_field = 1
-        doc.dict_field = {'hello': 'world'}
-        doc.list_field = ['1', 2, {'hello': 'world'}]
-        doc.save()
-        doc = doc.reload(10)
-
-        self.assertEqual(doc.string_field, 'hello')
-        self.assertEqual(doc.int_field, 1)
-        self.assertEqual(doc.dict_field, {'hello': 'world'})
-        self.assertEqual(doc.list_field, ['1', 2, {'hello': 'world'}])
-
-    def test_delta_recursive_db_field(self):
-        self.delta_recursive_db_field(Document, EmbeddedDocument)
-        self.delta_recursive_db_field(Document, DynamicEmbeddedDocument)
-        self.delta_recursive_db_field(DynamicDocument, EmbeddedDocument)
-        self.delta_recursive_db_field(DynamicDocument, DynamicEmbeddedDocument)
-
-    def delta_recursive_db_field(self, DocClass, EmbeddedClass):
-
-        class Embedded(EmbeddedClass):
-            string_field = StringField(db_field='db_string_field')
-            int_field = IntField(db_field='db_int_field')
-            dict_field = DictField(db_field='db_dict_field')
-            list_field = ListField(db_field='db_list_field')
-
-        class Doc(DocClass):
-            string_field = StringField(db_field='db_string_field')
-            int_field = IntField(db_field='db_int_field')
-            dict_field = DictField(db_field='db_dict_field')
-            list_field = ListField(db_field='db_list_field')
-            embedded_field = EmbeddedDocumentField(Embedded,
-                                    db_field='db_embedded_field')
-
-        Doc.drop_collection()
-        doc = Doc()
-        doc.save()
-
-        doc = Doc.objects.first()
-        self.assertEqual(doc._get_changed_fields(), [])
-        self.assertEqual(doc._delta(), ({}, {}))
-
-        embedded_1 = Embedded()
-        embedded_1.string_field = 'hello'
-        embedded_1.int_field = 1
-        embedded_1.dict_field = {'hello': 'world'}
-        embedded_1.list_field = ['1', 2, {'hello': 'world'}]
-        doc.embedded_field = embedded_1
-
-        self.assertEqual(doc._get_changed_fields(), ['db_embedded_field'])
-
-        embedded_delta = {
-            'db_string_field': 'hello',
-            'db_int_field': 1,
-            'db_dict_field': {'hello': 'world'},
-            'db_list_field': ['1', 2, {'hello': 'world'}]
-        }
-        self.assertEqual(doc.embedded_field._delta(), (embedded_delta, {}))
-        self.assertEqual(doc._delta(),
-            ({'db_embedded_field': embedded_delta}, {}))
-
-        doc.save()
-        doc = doc.reload(10)
-
-        doc.embedded_field.dict_field = {}
-        self.assertEqual(doc._get_changed_fields(),
-            ['db_embedded_field.db_dict_field'])
-        self.assertEqual(doc.embedded_field._delta(),
-            ({}, {'db_dict_field': 1}))
-        self.assertEqual(doc._delta(),
-            ({}, {'db_embedded_field.db_dict_field': 1}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.dict_field, {})
-
-        doc.embedded_field.list_field = []
-        self.assertEqual(doc._get_changed_fields(),
-            ['db_embedded_field.db_list_field'])
-        self.assertEqual(doc.embedded_field._delta(),
-            ({}, {'db_list_field': 1}))
-        self.assertEqual(doc._delta(),
-            ({}, {'db_embedded_field.db_list_field': 1}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field, [])
-
-        embedded_2 = Embedded()
-        embedded_2.string_field = 'hello'
-        embedded_2.int_field = 1
-        embedded_2.dict_field = {'hello': 'world'}
-        embedded_2.list_field = ['1', 2, {'hello': 'world'}]
-
-        doc.embedded_field.list_field = ['1', 2, embedded_2]
-        self.assertEqual(doc._get_changed_fields(),
-            ['db_embedded_field.db_list_field'])
-        self.assertEqual(doc.embedded_field._delta(), ({
-            'db_list_field': ['1', 2, {
-                '_cls': 'Embedded',
-                'db_string_field': 'hello',
-                'db_dict_field': {'hello': 'world'},
-                'db_int_field': 1,
-                'db_list_field': ['1', 2, {'hello': 'world'}],
-            }]
-        }, {}))
-
-        self.assertEqual(doc._delta(), ({
-            'db_embedded_field.db_list_field': ['1', 2, {
-                '_cls': 'Embedded',
-                'db_string_field': 'hello',
-                'db_dict_field': {'hello': 'world'},
-                'db_int_field': 1,
-                'db_list_field': ['1', 2, {'hello': 'world'}],
-            }]
-        }, {}))
-        doc.save()
-        doc = doc.reload(10)
-
-        self.assertEqual(doc.embedded_field.list_field[0], '1')
-        self.assertEqual(doc.embedded_field.list_field[1], 2)
-        for k in doc.embedded_field.list_field[2]._fields:
-            self.assertEqual(doc.embedded_field.list_field[2][k],
-                             embedded_2[k])
-
-        doc.embedded_field.list_field[2].string_field = 'world'
-        self.assertEqual(doc._get_changed_fields(),
-            ['db_embedded_field.db_list_field.2.db_string_field'])
-        self.assertEqual(doc.embedded_field._delta(),
-            ({'db_list_field.2.db_string_field': 'world'}, {}))
-        self.assertEqual(doc._delta(),
-            ({'db_embedded_field.db_list_field.2.db_string_field': 'world'},
-             {}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].string_field,
-                        'world')
-
-        # Test multiple assignments
-        doc.embedded_field.list_field[2].string_field = 'hello world'
-        doc.embedded_field.list_field[2] = doc.embedded_field.list_field[2]
-        self.assertEqual(doc._get_changed_fields(),
-            ['db_embedded_field.db_list_field.2'])
-        self.assertEqual(doc.embedded_field._delta(), ({'db_list_field.2': {
-            '_cls': 'Embedded',
-            'db_string_field': 'hello world',
-            'db_int_field': 1,
-            'db_list_field': ['1', 2, {'hello': 'world'}],
-            'db_dict_field': {'hello': 'world'}}}, {}))
-        self.assertEqual(doc._delta(), ({
-            'db_embedded_field.db_list_field.2': {
-                '_cls': 'Embedded',
-                'db_string_field': 'hello world',
-                'db_int_field': 1,
-                'db_list_field': ['1', 2, {'hello': 'world'}],
-                'db_dict_field': {'hello': 'world'}}
-            }, {}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].string_field,
-                        'hello world')
-
-        # Test list native methods
-        doc.embedded_field.list_field[2].list_field.pop(0)
-        self.assertEqual(doc._delta(),
-            ({'db_embedded_field.db_list_field.2.db_list_field':
-                [2, {'hello': 'world'}]}, {}))
-        doc.save()
-        doc = doc.reload(10)
-
-        doc.embedded_field.list_field[2].list_field.append(1)
-        self.assertEqual(doc._delta(),
-            ({'db_embedded_field.db_list_field.2.db_list_field':
-                [2, {'hello': 'world'}, 1]}, {}))
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].list_field,
-            [2, {'hello': 'world'}, 1])
-
-        doc.embedded_field.list_field[2].list_field.sort(key=str)
-        doc.save()
-        doc = doc.reload(10)
-        self.assertEqual(doc.embedded_field.list_field[2].list_field,
-            [1, 2, {'hello': 'world'}])
-
-        del doc.embedded_field.list_field[2].list_field[2]['hello']
-        self.assertEqual(doc._delta(),
-            ({}, {'db_embedded_field.db_list_field.2.db_list_field.2.hello': 1}))
-        doc.save()
-        doc = doc.reload(10)
-
-        del doc.embedded_field.list_field[2].list_field
-        self.assertEqual(doc._delta(), ({},
-            {'db_embedded_field.db_list_field.2.db_list_field': 1}))
-
-    def test_delta_for_dynamic_documents(self):
-        class Person(DynamicDocument):
-            name = StringField()
-            meta = {'allow_inheritance': True}
-
-        Person.drop_collection()
-
-        p = Person(name="James", age=34)
-        self.assertEqual(p._delta(), (
-            SON([('_cls', 'Person'), ('name', 'James'), ('age', 34)]), {}))
-
-        p.doc = 123
-        del p.doc
-        self.assertEqual(p._delta(), (
-            SON([('_cls', 'Person'), ('name', 'James'), ('age', 34)]), {}))
-
-        p = Person()
-        p.name = "Dean"
-        p.age = 22
-        p.save()
-
-        p.age = 24
-        self.assertEqual(p.age, 24)
-        self.assertEqual(p._get_changed_fields(), ['age'])
-        self.assertEqual(p._delta(), ({'age': 24}, {}))
-
-        p = Person.objects(age=22).get()
-        p.age = 24
-        self.assertEqual(p.age, 24)
-        self.assertEqual(p._get_changed_fields(), ['age'])
-        self.assertEqual(p._delta(), ({'age': 24}, {}))
-
-        p.save()
-        self.assertEqual(1, Person.objects(age=24).count())
-
-    def test_dynamic_delta(self):
-
-        class Doc(DynamicDocument):
-            pass
-
-        Doc.drop_collection()
-        doc = Doc()
-        doc.save()
-
-        doc = Doc.objects.first()
-        self.assertEqual(doc._get_changed_fields(), [])
-        self.assertEqual(doc._delta(), ({}, {}))
-
-        doc.string_field = 'hello'
-        self.assertEqual(doc._get_changed_fields(), ['string_field'])
-        self.assertEqual(doc._delta(), ({'string_field': 'hello'}, {}))
-
-        doc._changed_fields = []
-        doc.int_field = 1
-        self.assertEqual(doc._get_changed_fields(), ['int_field'])
-        self.assertEqual(doc._delta(), ({'int_field': 1}, {}))
-
-        doc._changed_fields = []
-        dict_value = {'hello': 'world', 'ping': 'pong'}
-        doc.dict_field = dict_value
-        self.assertEqual(doc._get_changed_fields(), ['dict_field'])
-        self.assertEqual(doc._delta(), ({'dict_field': dict_value}, {}))
-
-        doc._changed_fields = []
-        list_value = ['1', 2, {'hello': 'world'}]
-        doc.list_field = list_value
-        self.assertEqual(doc._get_changed_fields(), ['list_field'])
-        self.assertEqual(doc._delta(), ({'list_field': list_value}, {}))
-
-        # Test unsetting
-        doc._changed_fields = []
-        doc.dict_field = {}
-        self.assertEqual(doc._get_changed_fields(), ['dict_field'])
-        self.assertEqual(doc._delta(), ({}, {'dict_field': 1}))
-
-        doc._changed_fields = []
-        doc.list_field = []
-        self.assertEqual(doc._get_changed_fields(), ['list_field'])
-        self.assertEqual(doc._delta(), ({}, {'list_field': 1}))
-
-    def test_delta_with_dbref_true(self):
-        person, organization, employee = self.circular_reference_deltas_2(Document, Document, True)
-        employee.name = 'test'
-
-        self.assertEqual(organization._get_changed_fields(), [])
-
-        updates, removals = organization._delta()
-        self.assertEqual({}, removals)
-        self.assertEqual({}, updates)
-
-        organization.employees.append(person)
-        updates, removals = organization._delta()
-        self.assertEqual({}, removals)
-        self.assertIn('employees', updates)
-
-    def test_delta_with_dbref_false(self):
-        person, organization, employee = self.circular_reference_deltas_2(Document, Document, False)
-        employee.name = 'test'
-
-        self.assertEqual(organization._get_changed_fields(), [])
-
-        updates, removals = organization._delta()
-        self.assertEqual({}, removals)
-        self.assertEqual({}, updates)
-
-        organization.employees.append(person)
-        updates, removals = organization._delta()
-        self.assertEqual({}, removals)
-        self.assertIn('employees', updates)
-
-    def test_nested_nested_fields_mark_as_changed(self):
-        class EmbeddedDoc(EmbeddedDocument):
-            name = StringField()
-
-        class MyDoc(Document):
-            subs = MapField(MapField(EmbeddedDocumentField(EmbeddedDoc)))
-            name = StringField()
-
-        MyDoc.drop_collection()
-
-        mydoc = MyDoc(name='testcase1', subs={'a': {'b': EmbeddedDoc(name='foo')}}).save()
-
-        mydoc = MyDoc.objects.first()
-        subdoc = mydoc.subs['a']['b']
-        subdoc.name = 'bar'
-
-        self.assertEqual(["name"], subdoc._get_changed_fields())
-        self.assertEqual(["subs.a.b.name"], mydoc._get_changed_fields())
-
-        mydoc._clear_changed_fields()
-        self.assertEqual([], mydoc._get_changed_fields())
-
-    def test_lower_level_mark_as_changed(self):
-        class EmbeddedDoc(EmbeddedDocument):
-            name = StringField()
-
-        class MyDoc(Document):
-            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
-
-        MyDoc.drop_collection()
-
-        MyDoc().save()
-
-        mydoc = MyDoc.objects.first()
-        mydoc.subs['a'] = EmbeddedDoc()
-        self.assertEqual(["subs.a"], mydoc._get_changed_fields())
-
-        subdoc = mydoc.subs['a']
-        subdoc.name = 'bar'
-
-        self.assertEqual(["name"], subdoc._get_changed_fields())
-        self.assertEqual(["subs.a"], mydoc._get_changed_fields())
-        mydoc.save()
-
-        mydoc._clear_changed_fields()
-        self.assertEqual([], mydoc._get_changed_fields())
-
-    def test_upper_level_mark_as_changed(self):
-        class EmbeddedDoc(EmbeddedDocument):
-            name = StringField()
-
-        class MyDoc(Document):
-            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
-
-        MyDoc.drop_collection()
-
-        MyDoc(subs={'a': EmbeddedDoc(name='foo')}).save()
-
-        mydoc = MyDoc.objects.first()
-        subdoc = mydoc.subs['a']
-        subdoc.name = 'bar'
-
-        self.assertEqual(["name"], subdoc._get_changed_fields())
-        self.assertEqual(["subs.a.name"], mydoc._get_changed_fields())
-
-        mydoc.subs['a'] = EmbeddedDoc()
-        self.assertEqual(["subs.a"], mydoc._get_changed_fields())
-        mydoc.save()
-
-        mydoc._clear_changed_fields()
-        self.assertEqual([], mydoc._get_changed_fields())
-
-    def test_referenced_object_changed_attributes(self):
-        """Ensures that when you save a new reference to a field, the referenced object isn't altered"""
-
-        class Organization(Document):
-            name = StringField()
-
-        class User(Document):
-            name = StringField()
-            org = ReferenceField('Organization', required=True)
-
-        Organization.drop_collection()
-        User.drop_collection()
-
-        org1 = Organization(name='Org 1')
-        org1.save()
-
-        org2 = Organization(name='Org 2')
-        org2.save()
-
-        user = User(name='Fred', org=org1)
-        user.save()
-
-        org1.reload()
-        org2.reload()
-        user.reload()
-        self.assertEqual(org1.name, 'Org 1')
-        self.assertEqual(org2.name, 'Org 2')
-        self.assertEqual(user.name, 'Fred')
-
-        user.name = 'Harold'
-        user.org = org2
-
-        org2.name = 'New Org 2'
-        self.assertEqual(org2.name, 'New Org 2')
-
-        user.save()
-        org2.save()
-
-        self.assertEqual(org2.name, 'New Org 2')
-        org2.reload()
-        self.assertEqual(org2.name, 'New Org 2')
-
-    def test_delta_for_nested_map_fields(self):
-        class UInfoDocument(Document):
-            phone = StringField()
-
-        class EmbeddedRole(EmbeddedDocument):
-            type = StringField()
-
-        class EmbeddedUser(EmbeddedDocument):
-            name = StringField()
-            roles = MapField(field=EmbeddedDocumentField(EmbeddedRole))
-            rolist = ListField(field=EmbeddedDocumentField(EmbeddedRole))
-            info = ReferenceField(UInfoDocument)
-
-        class Doc(Document):
-            users = MapField(field=EmbeddedDocumentField(EmbeddedUser))
-            num = IntField(default=-1)
-
-        Doc.drop_collection()
-
-        doc = Doc(num=1)
-        doc.users["007"] = EmbeddedUser(name="Agent007")
-        doc.save()
-
-        uinfo = UInfoDocument(phone="79089269066")
-        uinfo.save()
-
-        d = Doc.objects(num=1).first()
-        d.users["007"]["roles"]["666"] = EmbeddedRole(type="superadmin")
-        d.users["007"]["rolist"].append(EmbeddedRole(type="oops"))
-        d.users["007"]["info"] = uinfo
-        delta = d._delta()
-        self.assertEqual(True, "users.007.roles.666" in delta[0])
-        self.assertEqual(True, "users.007.rolist" in delta[0])
-        self.assertEqual(True, "users.007.info" in delta[0])
-        self.assertEqual('superadmin', delta[0]["users.007.roles.666"]["type"])
-        self.assertEqual('oops', delta[0]["users.007.rolist"][0]["type"])
-        self.assertEqual(uinfo.id, delta[0]["users.007.info"])
-
-
-if __name__ == '__main__':
-    unittest.main()

tests/document/inheritance.py

@@ -1,564 +0,0 @@
-# -*- coding: utf-8 -*-
-import unittest
-import warnings
-
-from six import iteritems
-
-from mongoengine import (BooleanField, Document, EmbeddedDocument,
-                         EmbeddedDocumentField, GenericReferenceField,
-                         IntField, ReferenceField, StringField)
-from mongoengine.pymongo_support import list_collection_names
-from tests.utils import MongoDBTestCase
-from tests.fixtures import Base
-
-__all__ = ('InheritanceTest', )
-
-
-class InheritanceTest(MongoDBTestCase):
-
-    def tearDown(self):
-        for collection in list_collection_names(self.db):
-            self.db.drop_collection(collection)
-
-    def test_constructor_cls(self):
-        # Ensures _cls is properly set during construction
-        # and when object gets reloaded (prevent regression of #1950)
-        class EmbedData(EmbeddedDocument):
-            data = StringField()
-            meta = {'allow_inheritance': True}
-
-        class DataDoc(Document):
-            name = StringField()
-            embed = EmbeddedDocumentField(EmbedData)
-            meta = {'allow_inheritance': True}
-
-        test_doc = DataDoc(name='test', embed=EmbedData(data='data'))
-        self.assertEqual(test_doc._cls, 'DataDoc')
-        self.assertEqual(test_doc.embed._cls, 'EmbedData')
-        test_doc.save()
-        saved_doc = DataDoc.objects.with_id(test_doc.id)
-        self.assertEqual(test_doc._cls, saved_doc._cls)
-        self.assertEqual(test_doc.embed._cls, saved_doc.embed._cls)
-        test_doc.delete()
-
-    def test_superclasses(self):
-        """Ensure that the correct list of superclasses is assembled.
-        """
-        class Animal(Document):
-            meta = {'allow_inheritance': True}
-        class Fish(Animal): pass
-        class Guppy(Fish): pass
-        class Mammal(Animal): pass
-        class Dog(Mammal): pass
-        class Human(Mammal): pass
-
-        self.assertEqual(Animal._superclasses, ())
-        self.assertEqual(Fish._superclasses, ('Animal',))
-        self.assertEqual(Guppy._superclasses, ('Animal', 'Animal.Fish'))
-        self.assertEqual(Mammal._superclasses, ('Animal',))
-        self.assertEqual(Dog._superclasses, ('Animal', 'Animal.Mammal'))
-        self.assertEqual(Human._superclasses, ('Animal', 'Animal.Mammal'))
-
-    def test_external_superclasses(self):
-        """Ensure that the correct list of super classes is assembled when
-        importing part of the model.
-        """
-        class Animal(Base): pass
-        class Fish(Animal): pass
-        class Guppy(Fish): pass
-        class Mammal(Animal): pass
-        class Dog(Mammal): pass
-        class Human(Mammal): pass
-
-        self.assertEqual(Animal._superclasses, ('Base', ))
-        self.assertEqual(Fish._superclasses, ('Base', 'Base.Animal',))
-        self.assertEqual(Guppy._superclasses, ('Base', 'Base.Animal',
-                                               'Base.Animal.Fish'))
-        self.assertEqual(Mammal._superclasses, ('Base', 'Base.Animal',))
-        self.assertEqual(Dog._superclasses, ('Base', 'Base.Animal',
-                                             'Base.Animal.Mammal'))
-        self.assertEqual(Human._superclasses, ('Base', 'Base.Animal',
-                                               'Base.Animal.Mammal'))
-
-    def test_subclasses(self):
-        """Ensure that the correct list of _subclasses (subclasses) is
-        assembled.
-        """
-        class Animal(Document):
-            meta = {'allow_inheritance': True}
-        class Fish(Animal): pass
-        class Guppy(Fish): pass
-        class Mammal(Animal): pass
-        class Dog(Mammal): pass
-        class Human(Mammal): pass
-
-        self.assertEqual(Animal._subclasses, ('Animal',
-                                         'Animal.Fish',
-                                         'Animal.Fish.Guppy',
-                                         'Animal.Mammal',
-                                         'Animal.Mammal.Dog',
-                                         'Animal.Mammal.Human'))
-        self.assertEqual(Fish._subclasses, ('Animal.Fish',
-                                       'Animal.Fish.Guppy',))
-        self.assertEqual(Guppy._subclasses, ('Animal.Fish.Guppy',))
-        self.assertEqual(Mammal._subclasses, ('Animal.Mammal',
-                                         'Animal.Mammal.Dog',
-                                         'Animal.Mammal.Human'))
-        self.assertEqual(Human._subclasses, ('Animal.Mammal.Human',))
-
-    def test_external_subclasses(self):
-        """Ensure that the correct list of _subclasses (subclasses) is
-        assembled when importing part of the model.
-        """
-        class Animal(Base): pass
-        class Fish(Animal): pass
-        class Guppy(Fish): pass
-        class Mammal(Animal): pass
-        class Dog(Mammal): pass
-        class Human(Mammal): pass
-
-        self.assertEqual(Animal._subclasses, ('Base.Animal',
-                                              'Base.Animal.Fish',
-                                              'Base.Animal.Fish.Guppy',
-                                              'Base.Animal.Mammal',
-                                              'Base.Animal.Mammal.Dog',
-                                              'Base.Animal.Mammal.Human'))
-        self.assertEqual(Fish._subclasses, ('Base.Animal.Fish',
-                                            'Base.Animal.Fish.Guppy',))
-        self.assertEqual(Guppy._subclasses, ('Base.Animal.Fish.Guppy',))
-        self.assertEqual(Mammal._subclasses, ('Base.Animal.Mammal',
-                                              'Base.Animal.Mammal.Dog',
-                                              'Base.Animal.Mammal.Human'))
-        self.assertEqual(Human._subclasses, ('Base.Animal.Mammal.Human',))
-
-    def test_dynamic_declarations(self):
-        """Test that declaring an extra class updates meta data"""
-
-        class Animal(Document):
-            meta = {'allow_inheritance': True}
-
-        self.assertEqual(Animal._superclasses, ())
-        self.assertEqual(Animal._subclasses, ('Animal',))
-
-        # Test dynamically adding a class changes the meta data
-        class Fish(Animal):
-            pass
-
-        self.assertEqual(Animal._superclasses, ())
-        self.assertEqual(Animal._subclasses, ('Animal', 'Animal.Fish'))
-
-        self.assertEqual(Fish._superclasses, ('Animal', ))
-        self.assertEqual(Fish._subclasses, ('Animal.Fish',))
-
-        # Test dynamically adding an inherited class changes the meta data
-        class Pike(Fish):
-            pass
-
-        self.assertEqual(Animal._superclasses, ())
-        self.assertEqual(Animal._subclasses, ('Animal', 'Animal.Fish',
-                                              'Animal.Fish.Pike'))
-
-        self.assertEqual(Fish._superclasses, ('Animal', ))
-        self.assertEqual(Fish._subclasses, ('Animal.Fish', 'Animal.Fish.Pike'))
-
-        self.assertEqual(Pike._superclasses, ('Animal', 'Animal.Fish'))
-        self.assertEqual(Pike._subclasses, ('Animal.Fish.Pike',))
-
-    def test_inheritance_meta_data(self):
-        """Ensure that document may inherit fields from a superclass document.
-        """
-        class Person(Document):
-            name = StringField()
-            age = IntField()
-
-            meta = {'allow_inheritance': True}
-
-        class Employee(Person):
-            salary = IntField()
-
-        self.assertEqual(['_cls', 'age', 'id', 'name', 'salary'],
-                         sorted(Employee._fields.keys()))
-        self.assertEqual(Employee._get_collection_name(),
-                         Person._get_collection_name())
-
-    def test_inheritance_to_mongo_keys(self):
-        """Ensure that document may inherit fields from a superclass document.
-        """
-        class Person(Document):
-            name = StringField()
-            age = IntField()
-
-            meta = {'allow_inheritance': True}
-
-        class Employee(Person):
-            salary = IntField()
-
-        self.assertEqual(['_cls', 'age', 'id', 'name', 'salary'],
-                         sorted(Employee._fields.keys()))
-        self.assertEqual(Person(name="Bob", age=35).to_mongo().keys(),
-                         ['_cls', 'name', 'age'])
-        self.assertEqual(Employee(name="Bob", age=35, salary=0).to_mongo().keys(),
-                         ['_cls', 'name', 'age', 'salary'])
-        self.assertEqual(Employee._get_collection_name(),
-                         Person._get_collection_name())
-
-    def test_indexes_and_multiple_inheritance(self):
-        """ Ensure that all of the indexes are created for a document with
-        multiple inheritance.
-        """
-
-        class A(Document):
-            a = StringField()
-
-            meta = {
-                'allow_inheritance': True,
-                'indexes': ['a']
-            }
-
-        class B(Document):
-            b = StringField()
-
-            meta = {
-                'allow_inheritance': True,
-                'indexes': ['b']
-            }
-
-        class C(A, B):
-            pass
-
-        A.drop_collection()
-        B.drop_collection()
-        C.drop_collection()
-
-        C.ensure_indexes()
-
-        self.assertEqual(
-            sorted([idx['key'] for idx in C._get_collection().index_information().values()]),
-            sorted([[(u'_cls', 1), (u'b', 1)], [(u'_id', 1)], [(u'_cls', 1), (u'a', 1)]])
-        )
-
-    def test_polymorphic_queries(self):
-        """Ensure that the correct subclasses are returned from a query
-        """
-
-        class Animal(Document):
-            meta = {'allow_inheritance': True}
-        class Fish(Animal): pass
-        class Mammal(Animal): pass
-        class Dog(Mammal): pass
-        class Human(Mammal): pass
-
-        Animal.drop_collection()
-
-        Animal().save()
-        Fish().save()
-        Mammal().save()
-        Dog().save()
-        Human().save()
-
-        classes = [obj.__class__ for obj in Animal.objects]
-        self.assertEqual(classes, [Animal, Fish, Mammal, Dog, Human])
-
-        classes = [obj.__class__ for obj in Mammal.objects]
-        self.assertEqual(classes, [Mammal, Dog, Human])
-
-        classes = [obj.__class__ for obj in Human.objects]
-        self.assertEqual(classes, [Human])
-
-    def test_allow_inheritance(self):
-        """Ensure that inheritance is disabled by default on simple
-        classes and that _cls will not be used.
-        """
-        class Animal(Document):
-            name = StringField()
-
-        # can't inherit because Animal didn't explicitly allow inheritance
-        with self.assertRaises(ValueError) as cm:
-            class Dog(Animal):
-                pass
-        self.assertIn("Document Animal may not be subclassed", str(cm.exception))
-
-        # Check that _cls etc aren't present on simple documents
-        dog = Animal(name='dog').save()
-        self.assertEqual(dog.to_mongo().keys(), ['_id', 'name'])
-
-        collection = self.db[Animal._get_collection_name()]
-        obj = collection.find_one()
-        self.assertNotIn('_cls', obj)
-
-    def test_cant_turn_off_inheritance_on_subclass(self):
-        """Ensure if inheritance is on in a subclass you cant turn it off.
-        """
-        class Animal(Document):
-            name = StringField()
-            meta = {'allow_inheritance': True}
-
-        with self.assertRaises(ValueError) as cm:
-            class Mammal(Animal):
-                meta = {'allow_inheritance': False}
-        self.assertEqual(str(cm.exception), 'Only direct subclasses of Document may set "allow_inheritance" to False')
-
-    def test_allow_inheritance_abstract_document(self):
-        """Ensure that abstract documents can set inheritance rules and that
-        _cls will not be used.
-        """
-        class FinalDocument(Document):
-            meta = {'abstract': True,
-                    'allow_inheritance': False}
-
-        class Animal(FinalDocument):
-            name = StringField()
-
-        with self.assertRaises(ValueError) as cm:
-            class Mammal(Animal):
-                pass
-
-        # Check that _cls isn't present in simple documents
-        doc = Animal(name='dog')
-        self.assertNotIn('_cls', doc.to_mongo())
-
-    def test_using_abstract_class_in_reference_field(self):
-        # Ensures no regression of #1920
-        class AbstractHuman(Document):
-            meta = {'abstract': True}
-
-        class Dad(AbstractHuman):
-            name = StringField()
-
-        class Home(Document):
-            dad = ReferenceField(AbstractHuman)  # Referencing the abstract class
-            address = StringField()
-
-        dad = Dad(name='5').save()
-        Home(dad=dad, address='street').save()
-
-        home = Home.objects.first()
-        home.address = 'garbage'
-        home.save()     # Was failing with ValidationError
-
-    def test_abstract_class_referencing_self(self):
-        # Ensures no regression of #1920
-        class Human(Document):
-            meta = {'abstract': True}
-            creator = ReferenceField('self', dbref=True)
-
-        class User(Human):
-            name = StringField()
-
-        user = User(name='John').save()
-        user2 = User(name='Foo', creator=user).save()
-
-        user2 = User.objects.with_id(user2.id)
-        user2.name = 'Bar'
-        user2.save()    # Was failing with ValidationError
-
-    def test_abstract_handle_ids_in_metaclass_properly(self):
-
-        class City(Document):
-            continent = StringField()
-            meta = {'abstract': True,
-                    'allow_inheritance': False}
-
-        class EuropeanCity(City):
-            name = StringField()
-
-        berlin = EuropeanCity(name='Berlin', continent='Europe')
-        self.assertEqual(len(berlin._db_field_map), len(berlin._fields_ordered))
-        self.assertEqual(len(berlin._reverse_db_field_map), len(berlin._fields_ordered))
-        self.assertEqual(len(berlin._fields_ordered), 3)
-        self.assertEqual(berlin._fields_ordered[0], 'id')
-
-    def test_auto_id_not_set_if_specific_in_parent_class(self):
-
-        class City(Document):
-            continent = StringField()
-            city_id = IntField(primary_key=True)
-            meta = {'abstract': True,
-                    'allow_inheritance': False}
-
-        class EuropeanCity(City):
-            name = StringField()
-
-        berlin = EuropeanCity(name='Berlin', continent='Europe')
-        self.assertEqual(len(berlin._db_field_map), len(berlin._fields_ordered))
-        self.assertEqual(len(berlin._reverse_db_field_map), len(berlin._fields_ordered))
-        self.assertEqual(len(berlin._fields_ordered), 3)
-        self.assertEqual(berlin._fields_ordered[0], 'city_id')
-
-    def test_auto_id_vs_non_pk_id_field(self):
-
-        class City(Document):
-            continent = StringField()
-            id = IntField()
-            meta = {'abstract': True,
-                    'allow_inheritance': False}
-
-        class EuropeanCity(City):
-            name = StringField()
-
-        berlin = EuropeanCity(name='Berlin', continent='Europe')
-        self.assertEqual(len(berlin._db_field_map), len(berlin._fields_ordered))
-        self.assertEqual(len(berlin._reverse_db_field_map), len(berlin._fields_ordered))
-        self.assertEqual(len(berlin._fields_ordered), 4)
-        self.assertEqual(berlin._fields_ordered[0], 'auto_id_0')
-        berlin.save()
-        self.assertEqual(berlin.pk, berlin.auto_id_0)
-
-    def test_abstract_document_creation_does_not_fail(self):
-        class City(Document):
-            continent = StringField()
-            meta = {'abstract': True,
-                    'allow_inheritance': False}
-
-        city = City(continent='asia')
-        self.assertEqual(None, city.pk)
-        # TODO: expected error? Shouldn't we create a new error type?
-        with self.assertRaises(KeyError):
-            setattr(city, 'pk', 1)
-
-    def test_allow_inheritance_embedded_document(self):
-        """Ensure embedded documents respect inheritance."""
-        class Comment(EmbeddedDocument):
-            content = StringField()
-
-        with self.assertRaises(ValueError):
-            class SpecialComment(Comment):
-                pass
-
-        doc = Comment(content='test')
-        self.assertNotIn('_cls', doc.to_mongo())
-
-        class Comment(EmbeddedDocument):
-            content = StringField()
-            meta = {'allow_inheritance': True}
-
-        doc = Comment(content='test')
-        self.assertIn('_cls', doc.to_mongo())
-
-    def test_document_inheritance(self):
-        """Ensure mutliple inheritance of abstract documents
-        """
-        class DateCreatedDocument(Document):
-            meta = {
-                'allow_inheritance': True,
-                'abstract': True,
-            }
-
-        class DateUpdatedDocument(Document):
-            meta = {
-                'allow_inheritance': True,
-                'abstract': True,
-            }
-
-        try:
-            class MyDocument(DateCreatedDocument, DateUpdatedDocument):
-                pass
-        except Exception:
-            self.assertTrue(False, "Couldn't create MyDocument class")
-
-    def test_abstract_documents(self):
-        """Ensure that a document superclass can be marked as abstract
-        thereby not using it as the name for the collection."""
-
-        defaults = {'index_background': True,
-                    'index_drop_dups': True,
-                    'index_opts': {'hello': 'world'},
-                    'allow_inheritance': True,
-                    'queryset_class': 'QuerySet',
-                    'db_alias': 'myDB',
-                    'shard_key': ('hello', 'world')}
-
-        meta_settings = {'abstract': True}
-        meta_settings.update(defaults)
-
-        class Animal(Document):
-            name = StringField()
-            meta = meta_settings
-
-        class Fish(Animal): pass
-        class Guppy(Fish): pass
-
-        class Mammal(Animal):
-            meta = {'abstract': True}
-        class Human(Mammal): pass
-
-        for k, v in iteritems(defaults):
-            for cls in [Animal, Fish, Guppy]:
-                self.assertEqual(cls._meta[k], v)
-
-        self.assertNotIn('collection', Animal._meta)
-        self.assertNotIn('collection', Mammal._meta)
-
-        self.assertEqual(Animal._get_collection_name(), None)
-        self.assertEqual(Mammal._get_collection_name(), None)
-
-        self.assertEqual(Fish._get_collection_name(), 'fish')
-        self.assertEqual(Guppy._get_collection_name(), 'fish')
-        self.assertEqual(Human._get_collection_name(), 'human')
-
-        # ensure that a subclass of a non-abstract class can't be abstract
-        with self.assertRaises(ValueError):
-            class EvilHuman(Human):
-                evil = BooleanField(default=True)
-                meta = {'abstract': True}
-
-    def test_abstract_embedded_documents(self):
-        # 789: EmbeddedDocument shouldn't inherit abstract
-        class A(EmbeddedDocument):
-            meta = {"abstract": True}
-
-        class B(A):
-            pass
-
-        self.assertFalse(B._meta["abstract"])
-
-    def test_inherited_collections(self):
-        """Ensure that subclassed documents don't override parents'
-        collections
-        """
-
-        class Drink(Document):
-            name = StringField()
-            meta = {'allow_inheritance': True}
-
-        class Drinker(Document):
-            drink = GenericReferenceField()
-
-        try:
-            warnings.simplefilter("error")
-
-            class AcloholicDrink(Drink):
-                meta = {'collection': 'booze'}
-
-        except SyntaxWarning:
-            warnings.simplefilter("ignore")
-
-            class AlcoholicDrink(Drink):
-                meta = {'collection': 'booze'}
-
-        else:
-            raise AssertionError("SyntaxWarning should be triggered")
-
-        warnings.resetwarnings()
-
-        Drink.drop_collection()
-        AlcoholicDrink.drop_collection()
-        Drinker.drop_collection()
-
-        red_bull = Drink(name='Red Bull')
-        red_bull.save()
-
-        programmer = Drinker(drink=red_bull)
-        programmer.save()
-
-        beer = AlcoholicDrink(name='Beer')
-        beer.save()
-        real_person = Drinker(drink=beer)
-        real_person.save()
-
-        self.assertEqual(Drinker.objects[0].drink.name, red_bull.name)
-        self.assertEqual(Drinker.objects[1].drink.name, beer.name)
-
-
-if __name__ == '__main__':
-    unittest.main()

tests/document/test_class_methods.py

@@ -2,18 +2,14 @@
 import unittest
 
 from mongoengine import *
-from mongoengine.pymongo_support import list_collection_names
-
-from mongoengine.queryset import NULLIFY, PULL
 from mongoengine.connection import get_db
-
+from mongoengine.pymongo_support import list_collection_names
-__all__ = ("ClassMethodsTest", )
+from mongoengine.queryset import NULLIFY, PULL
 
 
-class ClassMethodsTest(unittest.TestCase):
+class TestClassMethods(unittest.TestCase):
-
     def setUp(self):
-        connect(db='mongoenginetest')
+        connect(db="mongoenginetest")
         self.db = get_db()
 
         class Person(Document):
@@ -33,54 +29,53 @@ class ClassMethodsTest(unittest.TestCase):
     def test_definition(self):
         """Ensure that document may be defined using fields.
         """
-        self.assertEqual(['_cls', 'age', 'id', 'name'],
+        assert ["_cls", "age", "id", "name"] == sorted(self.Person._fields.keys())
-                         sorted(self.Person._fields.keys()))
+        assert ["IntField", "ObjectIdField", "StringField", "StringField"] == sorted(
-        self.assertEqual(["IntField", "ObjectIdField", "StringField", "StringField"],
+            [x.__class__.__name__ for x in self.Person._fields.values()]
-                        sorted([x.__class__.__name__ for x in
+        )
-                                self.Person._fields.values()]))
 
     def test_get_db(self):
         """Ensure that get_db returns the expected db.
         """
         db = self.Person._get_db()
-        self.assertEqual(self.db, db)
+        assert self.db == db
 
     def test_get_collection_name(self):
         """Ensure that get_collection_name returns the expected collection
         name.
         """
-        collection_name = 'person'
+        collection_name = "person"
-        self.assertEqual(collection_name, self.Person._get_collection_name())
+        assert collection_name == self.Person._get_collection_name()
 
     def test_get_collection(self):
         """Ensure that get_collection returns the expected collection.
         """
-        collection_name = 'person'
+        collection_name = "person"
         collection = self.Person._get_collection()
-        self.assertEqual(self.db[collection_name], collection)
+        assert self.db[collection_name] == collection
 
     def test_drop_collection(self):
         """Ensure that the collection may be dropped from the database.
         """
-        collection_name = 'person'
+        collection_name = "person"
-        self.Person(name='Test').save()
+        self.Person(name="Test").save()
-        self.assertIn(collection_name, list_collection_names(self.db))
+        assert collection_name in list_collection_names(self.db)
 
         self.Person.drop_collection()
-        self.assertNotIn(collection_name, list_collection_names(self.db))
+        assert collection_name not in list_collection_names(self.db)
 
     def test_register_delete_rule(self):
         """Ensure that register delete rule adds a delete rule to the document
         meta.
         """
+
         class Job(Document):
             employee = ReferenceField(self.Person)
 
-        self.assertEqual(self.Person._meta.get('delete_rules'), None)
+        assert self.Person._meta.get("delete_rules") is None
 
-        self.Person.register_delete_rule(Job, 'employee', NULLIFY)
+        self.Person.register_delete_rule(Job, "employee", NULLIFY)
-        self.assertEqual(self.Person._meta['delete_rules'],
+        assert self.Person._meta["delete_rules"] == {(Job, "employee"): NULLIFY}
-                         {(Job, 'employee'): NULLIFY})
 
     def test_compare_indexes(self):
         """ Ensure that the indexes are properly created and that
@@ -93,23 +88,27 @@ class ClassMethodsTest(unittest.TestCase):
             description = StringField()
             tags = StringField()
 
-            meta = {
+            meta = {"indexes": [("author", "title")]}
-                'indexes': [('author', 'title')]
-            }
 
         BlogPost.drop_collection()
 
         BlogPost.ensure_indexes()
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
 
-        BlogPost.ensure_index(['author', 'description'])
+        BlogPost.ensure_index(["author", "description"])
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': [[('author', 1), ('description', 1)]]})
+        assert BlogPost.compare_indexes() == {
+            "missing": [],
+            "extra": [[("author", 1), ("description", 1)]],
+        }
 
-        BlogPost._get_collection().drop_index('author_1_description_1')
+        BlogPost._get_collection().drop_index("author_1_description_1")
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
 
-        BlogPost._get_collection().drop_index('author_1_title_1')
+        BlogPost._get_collection().drop_index("author_1_title_1")
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [[('author', 1), ('title', 1)]], 'extra': []})
+        assert BlogPost.compare_indexes() == {
+            "missing": [[("author", 1), ("title", 1)]],
+            "extra": [],
+        }
 
     def test_compare_indexes_inheritance(self):
         """ Ensure that the indexes are properly created and that
@@ -122,32 +121,34 @@ class ClassMethodsTest(unittest.TestCase):
             title = StringField()
             description = StringField()
 
-            meta = {
+            meta = {"allow_inheritance": True}
-                'allow_inheritance': True
-            }
 
         class BlogPostWithTags(BlogPost):
             tags = StringField()
             tag_list = ListField(StringField())
 
-            meta = {
+            meta = {"indexes": [("author", "tags")]}
-                'indexes': [('author', 'tags')]
-            }
 
         BlogPost.drop_collection()
 
         BlogPost.ensure_indexes()
         BlogPostWithTags.ensure_indexes()
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
 
-        BlogPostWithTags.ensure_index(['author', 'tag_list'])
+        BlogPostWithTags.ensure_index(["author", "tag_list"])
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': [[('_cls', 1), ('author', 1), ('tag_list', 1)]]})
+        assert BlogPost.compare_indexes() == {
+            "missing": [],
+            "extra": [[("_cls", 1), ("author", 1), ("tag_list", 1)]],
+        }
 
-        BlogPostWithTags._get_collection().drop_index('_cls_1_author_1_tag_list_1')
+        BlogPostWithTags._get_collection().drop_index("_cls_1_author_1_tag_list_1")
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
 
-        BlogPostWithTags._get_collection().drop_index('_cls_1_author_1_tags_1')
+        BlogPostWithTags._get_collection().drop_index("_cls_1_author_1_tags_1")
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [[('_cls', 1), ('author', 1), ('tags', 1)]], 'extra': []})
+        assert BlogPost.compare_indexes() == {
+            "missing": [[("_cls", 1), ("author", 1), ("tags", 1)]],
+            "extra": [],
+        }
 
     def test_compare_indexes_multiple_subclasses(self):
         """ Ensure that compare_indexes behaves correctly if called from a
@@ -159,32 +160,26 @@ class ClassMethodsTest(unittest.TestCase):
             title = StringField()
             description = StringField()
 
-            meta = {
+            meta = {"allow_inheritance": True}
-                'allow_inheritance': True
-            }
 
         class BlogPostWithTags(BlogPost):
             tags = StringField()
             tag_list = ListField(StringField())
 
-            meta = {
+            meta = {"indexes": [("author", "tags")]}
-                'indexes': [('author', 'tags')]
-            }
 
         class BlogPostWithCustomField(BlogPost):
             custom = DictField()
 
-            meta = {
+            meta = {"indexes": [("author", "custom")]}
-                'indexes': [('author', 'custom')]
-            }
 
         BlogPost.ensure_indexes()
         BlogPostWithTags.ensure_indexes()
         BlogPostWithCustomField.ensure_indexes()
 
-        self.assertEqual(BlogPost.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
-        self.assertEqual(BlogPostWithTags.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPostWithTags.compare_indexes() == {"missing": [], "extra": []}
-        self.assertEqual(BlogPostWithCustomField.compare_indexes(), {'missing': [], 'extra': []})
+        assert BlogPostWithCustomField.compare_indexes() == {"missing": [], "extra": []}
 
     def test_compare_indexes_for_text_indexes(self):
         """ Ensure that compare_indexes behaves correctly for text indexes """
@@ -192,18 +187,21 @@ class ClassMethodsTest(unittest.TestCase):
         class Doc(Document):
             a = StringField()
             b = StringField()
-            meta = {'indexes': [
+            meta = {
-                {'fields': ['$a', "$b"],
+                "indexes": [
-                 'default_language': 'english',
+                    {
-                 'weights': {'a': 10, 'b': 2}
+                        "fields": ["$a", "$b"],
-                }
+                        "default_language": "english",
-            ]}
+                        "weights": {"a": 10, "b": 2},
+                    }
+                ]
+            }
 
         Doc.drop_collection()
         Doc.ensure_indexes()
         actual = Doc.compare_indexes()
-        expected = {'missing': [], 'extra': []}
+        expected = {"missing": [], "extra": []}
-        self.assertEqual(actual, expected)
+        assert actual == expected
 
     def test_list_indexes_inheritance(self):
         """ ensure that all of the indexes are listed regardless of the super-
@@ -215,23 +213,17 @@ class ClassMethodsTest(unittest.TestCase):
             title = StringField()
             description = StringField()
 
-            meta = {
+            meta = {"allow_inheritance": True}
-                'allow_inheritance': True
-            }
 
         class BlogPostWithTags(BlogPost):
             tags = StringField()
 
-            meta = {
+            meta = {"indexes": [("author", "tags")]}
-                'indexes': [('author', 'tags')]
-            }
 
         class BlogPostWithTagsAndExtraText(BlogPostWithTags):
             extra_text = StringField()
 
-            meta = {
+            meta = {"indexes": [("author", "tags", "extra_text")]}
-                'indexes': [('author', 'tags', 'extra_text')]
-            }
 
         BlogPost.drop_collection()
 
@@ -239,17 +231,16 @@ class ClassMethodsTest(unittest.TestCase):
         BlogPostWithTags.ensure_indexes()
         BlogPostWithTagsAndExtraText.ensure_indexes()
 
-        self.assertEqual(BlogPost.list_indexes(),
+        assert BlogPost.list_indexes() == BlogPostWithTags.list_indexes()
-                         BlogPostWithTags.list_indexes())
+        assert BlogPost.list_indexes() == BlogPostWithTagsAndExtraText.list_indexes()
-        self.assertEqual(BlogPost.list_indexes(),
+        assert BlogPost.list_indexes() == [
-                         BlogPostWithTagsAndExtraText.list_indexes())
+            [("_cls", 1), ("author", 1), ("tags", 1)],
-        self.assertEqual(BlogPost.list_indexes(),
+            [("_cls", 1), ("author", 1), ("tags", 1), ("extra_text", 1)],
-                         [[('_cls', 1), ('author', 1), ('tags', 1)],
+            [(u"_id", 1)],
-                         [('_cls', 1), ('author', 1), ('tags', 1), ('extra_text', 1)],
+            [("_cls", 1)],
-                         [(u'_id', 1)], [('_cls', 1)]])
+        ]
 
     def test_register_delete_rule_inherited(self):
-
         class Vaccine(Document):
             name = StringField(required=True)
 
@@ -257,15 +248,17 @@ class ClassMethodsTest(unittest.TestCase):
 
         class Animal(Document):
             family = StringField(required=True)
-            vaccine_made = ListField(ReferenceField("Vaccine", reverse_delete_rule=PULL))
+            vaccine_made = ListField(
+                ReferenceField("Vaccine", reverse_delete_rule=PULL)
+            )
 
             meta = {"allow_inheritance": True, "indexes": ["family"]}
 
         class Cat(Animal):
             name = StringField(required=True)
 
-        self.assertEqual(Vaccine._meta['delete_rules'][(Animal, 'vaccine_made')], PULL)
+        assert Vaccine._meta["delete_rules"][(Animal, "vaccine_made")] == PULL
-        self.assertEqual(Vaccine._meta['delete_rules'][(Cat, 'vaccine_made')], PULL)
+        assert Vaccine._meta["delete_rules"][(Cat, "vaccine_made")] == PULL
 
     def test_collection_naming(self):
         """Ensure that a collection with a specified name may be used.
@@ -273,80 +266,76 @@ class ClassMethodsTest(unittest.TestCase):
 
         class DefaultNamingTest(Document):
             pass
-        self.assertEqual('default_naming_test',
+
-                         DefaultNamingTest._get_collection_name())
+        assert "default_naming_test" == DefaultNamingTest._get_collection_name()
 
         class CustomNamingTest(Document):
-            meta = {'collection': 'pimp_my_collection'}
+            meta = {"collection": "pimp_my_collection"}
 
-        self.assertEqual('pimp_my_collection',
+        assert "pimp_my_collection" == CustomNamingTest._get_collection_name()
-                         CustomNamingTest._get_collection_name())
 
         class DynamicNamingTest(Document):
-            meta = {'collection': lambda c: "DYNAMO"}
+            meta = {"collection": lambda c: "DYNAMO"}
-        self.assertEqual('DYNAMO', DynamicNamingTest._get_collection_name())
+
+        assert "DYNAMO" == DynamicNamingTest._get_collection_name()
 
         # Use Abstract class to handle backwards compatibility
         class BaseDocument(Document):
-            meta = {
+            meta = {"abstract": True, "collection": lambda c: c.__name__.lower()}
-                'abstract': True,
-                'collection': lambda c: c.__name__.lower()
-            }
 
         class OldNamingConvention(BaseDocument):
             pass
-        self.assertEqual('oldnamingconvention',
+
-                         OldNamingConvention._get_collection_name())
+        assert "oldnamingconvention" == OldNamingConvention._get_collection_name()
 
         class InheritedAbstractNamingTest(BaseDocument):
-            meta = {'collection': 'wibble'}
+            meta = {"collection": "wibble"}
-        self.assertEqual('wibble',
+
-                         InheritedAbstractNamingTest._get_collection_name())
+        assert "wibble" == InheritedAbstractNamingTest._get_collection_name()
 
         # Mixin tests
         class BaseMixin(object):
-            meta = {
+            meta = {"collection": lambda c: c.__name__.lower()}
-                'collection': lambda c: c.__name__.lower()
-            }
 
         class OldMixinNamingConvention(Document, BaseMixin):
             pass
-        self.assertEqual('oldmixinnamingconvention',
+
-                          OldMixinNamingConvention._get_collection_name())
+        assert (
+            "oldmixinnamingconvention"
+            == OldMixinNamingConvention._get_collection_name()
+        )
 
         class BaseMixin(object):
-            meta = {
+            meta = {"collection": lambda c: c.__name__.lower()}
-                'collection': lambda c: c.__name__.lower()
-            }
 
         class BaseDocument(Document, BaseMixin):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
         class MyDocument(BaseDocument):
             pass
 
-        self.assertEqual('basedocument', MyDocument._get_collection_name())
+        assert "basedocument" == MyDocument._get_collection_name()
 
     def test_custom_collection_name_operations(self):
         """Ensure that a collection with a specified name is used as expected.
         """
-        collection_name = 'personCollTest'
+        collection_name = "personCollTest"
 
         class Person(Document):
             name = StringField()
-            meta = {'collection': collection_name}
+            meta = {"collection": collection_name}
 
         Person(name="Test User").save()
-        self.assertIn(collection_name, list_collection_names(self.db))
+        assert collection_name in list_collection_names(self.db)
 
         user_obj = self.db[collection_name].find_one()
-        self.assertEqual(user_obj['name'], "Test User")
+        assert user_obj["name"] == "Test User"
 
         user_obj = Person.objects[0]
-        self.assertEqual(user_obj.name, "Test User")
+        assert user_obj.name == "Test User"
 
         Person.drop_collection()
-        self.assertNotIn(collection_name, list_collection_names(self.db))
+        assert collection_name not in list_collection_names(self.db)
 
     def test_collection_name_and_primary(self):
         """Ensure that a collection with a specified name may be used.
@@ -354,15 +343,15 @@ class ClassMethodsTest(unittest.TestCase):
 
         class Person(Document):
             name = StringField(primary_key=True)
-            meta = {'collection': 'app'}
+            meta = {"collection": "app"}
 
         Person(name="Test User").save()
 
         user_obj = Person.objects.first()
-        self.assertEqual(user_obj.name, "Test User")
+        assert user_obj.name == "Test User"
 
         Person.drop_collection()
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/document/test_delta.py

@@ -0,0 +1,926 @@
+# -*- coding: utf-8 -*-
+import unittest
+
+from bson import SON
+from mongoengine import *
+from mongoengine.pymongo_support import list_collection_names
+from tests.utils import MongoDBTestCase
+
+
+class TestDelta(MongoDBTestCase):
+    def setUp(self):
+        super(TestDelta, self).setUp()
+
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+            non_field = True
+
+            meta = {"allow_inheritance": True}
+
+        self.Person = Person
+
+    def tearDown(self):
+        for collection in list_collection_names(self.db):
+            self.db.drop_collection(collection)
+
+    def test_delta(self):
+        self.delta(Document)
+        self.delta(DynamicDocument)
+
+    @staticmethod
+    def delta(DocClass):
+        class Doc(DocClass):
+            string_field = StringField()
+            int_field = IntField()
+            dict_field = DictField()
+            list_field = ListField()
+
+        Doc.drop_collection()
+        doc = Doc()
+        doc.save()
+
+        doc = Doc.objects.first()
+        assert doc._get_changed_fields() == []
+        assert doc._delta() == ({}, {})
+
+        doc.string_field = "hello"
+        assert doc._get_changed_fields() == ["string_field"]
+        assert doc._delta() == ({"string_field": "hello"}, {})
+
+        doc._changed_fields = []
+        doc.int_field = 1
+        assert doc._get_changed_fields() == ["int_field"]
+        assert doc._delta() == ({"int_field": 1}, {})
+
+        doc._changed_fields = []
+        dict_value = {"hello": "world", "ping": "pong"}
+        doc.dict_field = dict_value
+        assert doc._get_changed_fields() == ["dict_field"]
+        assert doc._delta() == ({"dict_field": dict_value}, {})
+
+        doc._changed_fields = []
+        list_value = ["1", 2, {"hello": "world"}]
+        doc.list_field = list_value
+        assert doc._get_changed_fields() == ["list_field"]
+        assert doc._delta() == ({"list_field": list_value}, {})
+
+        # Test unsetting
+        doc._changed_fields = []
+        doc.dict_field = {}
+        assert doc._get_changed_fields() == ["dict_field"]
+        assert doc._delta() == ({}, {"dict_field": 1})
+
+        doc._changed_fields = []
+        doc.list_field = []
+        assert doc._get_changed_fields() == ["list_field"]
+        assert doc._delta() == ({}, {"list_field": 1})
+
+    def test_delta_recursive(self):
+        self.delta_recursive(Document, EmbeddedDocument)
+        self.delta_recursive(DynamicDocument, EmbeddedDocument)
+        self.delta_recursive(Document, DynamicEmbeddedDocument)
+        self.delta_recursive(DynamicDocument, DynamicEmbeddedDocument)
+
+    def delta_recursive(self, DocClass, EmbeddedClass):
+        class Embedded(EmbeddedClass):
+            id = StringField()
+            string_field = StringField()
+            int_field = IntField()
+            dict_field = DictField()
+            list_field = ListField()
+
+        class Doc(DocClass):
+            string_field = StringField()
+            int_field = IntField()
+            dict_field = DictField()
+            list_field = ListField()
+            embedded_field = EmbeddedDocumentField(Embedded)
+
+        Doc.drop_collection()
+        doc = Doc()
+        doc.save()
+
+        doc = Doc.objects.first()
+        assert doc._get_changed_fields() == []
+        assert doc._delta() == ({}, {})
+
+        embedded_1 = Embedded()
+        embedded_1.id = "010101"
+        embedded_1.string_field = "hello"
+        embedded_1.int_field = 1
+        embedded_1.dict_field = {"hello": "world"}
+        embedded_1.list_field = ["1", 2, {"hello": "world"}]
+        doc.embedded_field = embedded_1
+
+        assert doc._get_changed_fields() == ["embedded_field"]
+
+        embedded_delta = {
+            "id": "010101",
+            "string_field": "hello",
+            "int_field": 1,
+            "dict_field": {"hello": "world"},
+            "list_field": ["1", 2, {"hello": "world"}],
+        }
+        assert doc.embedded_field._delta() == (embedded_delta, {})
+        assert doc._delta() == ({"embedded_field": embedded_delta}, {})
+
+        doc.save()
+        doc = doc.reload(10)
+
+        doc.embedded_field.dict_field = {}
+        assert doc._get_changed_fields() == ["embedded_field.dict_field"]
+        assert doc.embedded_field._delta() == ({}, {"dict_field": 1})
+        assert doc._delta() == ({}, {"embedded_field.dict_field": 1})
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.dict_field == {}
+
+        doc.embedded_field.list_field = []
+        assert doc._get_changed_fields() == ["embedded_field.list_field"]
+        assert doc.embedded_field._delta() == ({}, {"list_field": 1})
+        assert doc._delta() == ({}, {"embedded_field.list_field": 1})
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field == []
+
+        embedded_2 = Embedded()
+        embedded_2.string_field = "hello"
+        embedded_2.int_field = 1
+        embedded_2.dict_field = {"hello": "world"}
+        embedded_2.list_field = ["1", 2, {"hello": "world"}]
+
+        doc.embedded_field.list_field = ["1", 2, embedded_2]
+        assert doc._get_changed_fields() == ["embedded_field.list_field"]
+
+        assert doc.embedded_field._delta() == (
+            {
+                "list_field": [
+                    "1",
+                    2,
+                    {
+                        "_cls": "Embedded",
+                        "string_field": "hello",
+                        "dict_field": {"hello": "world"},
+                        "int_field": 1,
+                        "list_field": ["1", 2, {"hello": "world"}],
+                    },
+                ]
+            },
+            {},
+        )
+
+        assert doc._delta() == (
+            {
+                "embedded_field.list_field": [
+                    "1",
+                    2,
+                    {
+                        "_cls": "Embedded",
+                        "string_field": "hello",
+                        "dict_field": {"hello": "world"},
+                        "int_field": 1,
+                        "list_field": ["1", 2, {"hello": "world"}],
+                    },
+                ]
+            },
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+
+        assert doc.embedded_field.list_field[0] == "1"
+        assert doc.embedded_field.list_field[1] == 2
+        for k in doc.embedded_field.list_field[2]._fields:
+            assert doc.embedded_field.list_field[2][k] == embedded_2[k]
+
+        doc.embedded_field.list_field[2].string_field = "world"
+        assert doc._get_changed_fields() == ["embedded_field.list_field.2.string_field"]
+        assert doc.embedded_field._delta() == (
+            {"list_field.2.string_field": "world"},
+            {},
+        )
+        assert doc._delta() == (
+            {"embedded_field.list_field.2.string_field": "world"},
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].string_field == "world"
+
+        # Test multiple assignments
+        doc.embedded_field.list_field[2].string_field = "hello world"
+        doc.embedded_field.list_field[2] = doc.embedded_field.list_field[2]
+        assert doc._get_changed_fields() == ["embedded_field.list_field.2"]
+        assert doc.embedded_field._delta() == (
+            {
+                "list_field.2": {
+                    "_cls": "Embedded",
+                    "string_field": "hello world",
+                    "int_field": 1,
+                    "list_field": ["1", 2, {"hello": "world"}],
+                    "dict_field": {"hello": "world"},
+                }
+            },
+            {},
+        )
+        assert doc._delta() == (
+            {
+                "embedded_field.list_field.2": {
+                    "_cls": "Embedded",
+                    "string_field": "hello world",
+                    "int_field": 1,
+                    "list_field": ["1", 2, {"hello": "world"}],
+                    "dict_field": {"hello": "world"},
+                }
+            },
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].string_field == "hello world"
+
+        # Test list native methods
+        doc.embedded_field.list_field[2].list_field.pop(0)
+        assert doc._delta() == (
+            {"embedded_field.list_field.2.list_field": [2, {"hello": "world"}]},
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+
+        doc.embedded_field.list_field[2].list_field.append(1)
+        assert doc._delta() == (
+            {"embedded_field.list_field.2.list_field": [2, {"hello": "world"}, 1]},
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].list_field == [2, {"hello": "world"}, 1]
+
+        doc.embedded_field.list_field[2].list_field.sort(key=str)
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].list_field == [1, 2, {"hello": "world"}]
+
+        del doc.embedded_field.list_field[2].list_field[2]["hello"]
+        assert doc._delta() == (
+            {},
+            {"embedded_field.list_field.2.list_field.2.hello": 1},
+        )
+        doc.save()
+        doc = doc.reload(10)
+
+        del doc.embedded_field.list_field[2].list_field
+        assert doc._delta() == ({}, {"embedded_field.list_field.2.list_field": 1})
+
+        doc.save()
+        doc = doc.reload(10)
+
+        doc.dict_field["Embedded"] = embedded_1
+        doc.save()
+        doc = doc.reload(10)
+
+        doc.dict_field["Embedded"].string_field = "Hello World"
+        assert doc._get_changed_fields() == ["dict_field.Embedded.string_field"]
+        assert doc._delta() == ({"dict_field.Embedded.string_field": "Hello World"}, {})
+
+    def test_circular_reference_deltas(self):
+        self.circular_reference_deltas(Document, Document)
+        self.circular_reference_deltas(Document, DynamicDocument)
+        self.circular_reference_deltas(DynamicDocument, Document)
+        self.circular_reference_deltas(DynamicDocument, DynamicDocument)
+
+    def circular_reference_deltas(self, DocClass1, DocClass2):
+        class Person(DocClass1):
+            name = StringField()
+            owns = ListField(ReferenceField("Organization"))
+
+        class Organization(DocClass2):
+            name = StringField()
+            owner = ReferenceField("Person")
+
+        Person.drop_collection()
+        Organization.drop_collection()
+
+        person = Person(name="owner").save()
+        organization = Organization(name="company").save()
+
+        person.owns.append(organization)
+        organization.owner = person
+
+        person.save()
+        organization.save()
+
+        p = Person.objects[0].select_related()
+        o = Organization.objects.first()
+        assert p.owns[0] == o
+        assert o.owner == p
+
+    def test_circular_reference_deltas_2(self):
+        self.circular_reference_deltas_2(Document, Document)
+        self.circular_reference_deltas_2(Document, DynamicDocument)
+        self.circular_reference_deltas_2(DynamicDocument, Document)
+        self.circular_reference_deltas_2(DynamicDocument, DynamicDocument)
+
+    def circular_reference_deltas_2(self, DocClass1, DocClass2, dbref=True):
+        class Person(DocClass1):
+            name = StringField()
+            owns = ListField(ReferenceField("Organization", dbref=dbref))
+            employer = ReferenceField("Organization", dbref=dbref)
+
+        class Organization(DocClass2):
+            name = StringField()
+            owner = ReferenceField("Person", dbref=dbref)
+            employees = ListField(ReferenceField("Person", dbref=dbref))
+
+        Person.drop_collection()
+        Organization.drop_collection()
+
+        person = Person(name="owner").save()
+        employee = Person(name="employee").save()
+        organization = Organization(name="company").save()
+
+        person.owns.append(organization)
+        organization.owner = person
+
+        organization.employees.append(employee)
+        employee.employer = organization
+
+        person.save()
+        organization.save()
+        employee.save()
+
+        p = Person.objects.get(name="owner")
+        e = Person.objects.get(name="employee")
+        o = Organization.objects.first()
+
+        assert p.owns[0] == o
+        assert o.owner == p
+        assert e.employer == o
+
+        return person, organization, employee
+
+    def test_delta_db_field(self):
+        self.delta_db_field(Document)
+        self.delta_db_field(DynamicDocument)
+
+    def delta_db_field(self, DocClass):
+        class Doc(DocClass):
+            string_field = StringField(db_field="db_string_field")
+            int_field = IntField(db_field="db_int_field")
+            dict_field = DictField(db_field="db_dict_field")
+            list_field = ListField(db_field="db_list_field")
+
+        Doc.drop_collection()
+        doc = Doc()
+        doc.save()
+
+        doc = Doc.objects.first()
+        assert doc._get_changed_fields() == []
+        assert doc._delta() == ({}, {})
+
+        doc.string_field = "hello"
+        assert doc._get_changed_fields() == ["db_string_field"]
+        assert doc._delta() == ({"db_string_field": "hello"}, {})
+
+        doc._changed_fields = []
+        doc.int_field = 1
+        assert doc._get_changed_fields() == ["db_int_field"]
+        assert doc._delta() == ({"db_int_field": 1}, {})
+
+        doc._changed_fields = []
+        dict_value = {"hello": "world", "ping": "pong"}
+        doc.dict_field = dict_value
+        assert doc._get_changed_fields() == ["db_dict_field"]
+        assert doc._delta() == ({"db_dict_field": dict_value}, {})
+
+        doc._changed_fields = []
+        list_value = ["1", 2, {"hello": "world"}]
+        doc.list_field = list_value
+        assert doc._get_changed_fields() == ["db_list_field"]
+        assert doc._delta() == ({"db_list_field": list_value}, {})
+
+        # Test unsetting
+        doc._changed_fields = []
+        doc.dict_field = {}
+        assert doc._get_changed_fields() == ["db_dict_field"]
+        assert doc._delta() == ({}, {"db_dict_field": 1})
+
+        doc._changed_fields = []
+        doc.list_field = []
+        assert doc._get_changed_fields() == ["db_list_field"]
+        assert doc._delta() == ({}, {"db_list_field": 1})
+
+        # Test it saves that data
+        doc = Doc()
+        doc.save()
+
+        doc.string_field = "hello"
+        doc.int_field = 1
+        doc.dict_field = {"hello": "world"}
+        doc.list_field = ["1", 2, {"hello": "world"}]
+        doc.save()
+        doc = doc.reload(10)
+
+        assert doc.string_field == "hello"
+        assert doc.int_field == 1
+        assert doc.dict_field == {"hello": "world"}
+        assert doc.list_field == ["1", 2, {"hello": "world"}]
+
+    def test_delta_recursive_db_field_on_doc_and_embeddeddoc(self):
+        self.delta_recursive_db_field(Document, EmbeddedDocument)
+
+    def test_delta_recursive_db_field_on_doc_and_dynamicembeddeddoc(self):
+        self.delta_recursive_db_field(Document, DynamicEmbeddedDocument)
+
+    def test_delta_recursive_db_field_on_dynamicdoc_and_embeddeddoc(self):
+        self.delta_recursive_db_field(DynamicDocument, EmbeddedDocument)
+
+    def test_delta_recursive_db_field_on_dynamicdoc_and_dynamicembeddeddoc(self):
+        self.delta_recursive_db_field(DynamicDocument, DynamicEmbeddedDocument)
+
+    @staticmethod
+    def delta_recursive_db_field(DocClass, EmbeddedClass):
+        class Embedded(EmbeddedClass):
+            string_field = StringField(db_field="db_string_field")
+            int_field = IntField(db_field="db_int_field")
+            dict_field = DictField(db_field="db_dict_field")
+            list_field = ListField(db_field="db_list_field")
+
+        class Doc(DocClass):
+            string_field = StringField(db_field="db_string_field")
+            int_field = IntField(db_field="db_int_field")
+            dict_field = DictField(db_field="db_dict_field")
+            list_field = ListField(db_field="db_list_field")
+            embedded_field = EmbeddedDocumentField(
+                Embedded, db_field="db_embedded_field"
+            )
+
+        Doc.drop_collection()
+        doc = Doc()
+        doc.save()
+
+        doc = Doc.objects.first()
+        assert doc._get_changed_fields() == []
+        assert doc._delta() == ({}, {})
+
+        embedded_1 = Embedded()
+        embedded_1.string_field = "hello"
+        embedded_1.int_field = 1
+        embedded_1.dict_field = {"hello": "world"}
+        embedded_1.list_field = ["1", 2, {"hello": "world"}]
+        doc.embedded_field = embedded_1
+
+        assert doc._get_changed_fields() == ["db_embedded_field"]
+
+        embedded_delta = {
+            "db_string_field": "hello",
+            "db_int_field": 1,
+            "db_dict_field": {"hello": "world"},
+            "db_list_field": ["1", 2, {"hello": "world"}],
+        }
+        assert doc.embedded_field._delta() == (embedded_delta, {})
+        assert doc._delta() == ({"db_embedded_field": embedded_delta}, {})
+
+        doc.save()
+        doc = doc.reload(10)
+
+        doc.embedded_field.dict_field = {}
+        assert doc._get_changed_fields() == ["db_embedded_field.db_dict_field"]
+        assert doc.embedded_field._delta() == ({}, {"db_dict_field": 1})
+        assert doc._delta() == ({}, {"db_embedded_field.db_dict_field": 1})
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.dict_field == {}
+
+        assert doc._get_changed_fields() == []
+        doc.embedded_field.list_field = []
+        assert doc._get_changed_fields() == ["db_embedded_field.db_list_field"]
+        assert doc.embedded_field._delta() == ({}, {"db_list_field": 1})
+        assert doc._delta() == ({}, {"db_embedded_field.db_list_field": 1})
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field == []
+
+        embedded_2 = Embedded()
+        embedded_2.string_field = "hello"
+        embedded_2.int_field = 1
+        embedded_2.dict_field = {"hello": "world"}
+        embedded_2.list_field = ["1", 2, {"hello": "world"}]
+
+        doc.embedded_field.list_field = ["1", 2, embedded_2]
+        assert doc._get_changed_fields() == ["db_embedded_field.db_list_field"]
+        assert doc.embedded_field._delta() == (
+            {
+                "db_list_field": [
+                    "1",
+                    2,
+                    {
+                        "_cls": "Embedded",
+                        "db_string_field": "hello",
+                        "db_dict_field": {"hello": "world"},
+                        "db_int_field": 1,
+                        "db_list_field": ["1", 2, {"hello": "world"}],
+                    },
+                ]
+            },
+            {},
+        )
+
+        assert doc._delta() == (
+            {
+                "db_embedded_field.db_list_field": [
+                    "1",
+                    2,
+                    {
+                        "_cls": "Embedded",
+                        "db_string_field": "hello",
+                        "db_dict_field": {"hello": "world"},
+                        "db_int_field": 1,
+                        "db_list_field": ["1", 2, {"hello": "world"}],
+                    },
+                ]
+            },
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+
+        assert doc.embedded_field.list_field[0] == "1"
+        assert doc.embedded_field.list_field[1] == 2
+        for k in doc.embedded_field.list_field[2]._fields:
+            assert doc.embedded_field.list_field[2][k] == embedded_2[k]
+
+        doc.embedded_field.list_field[2].string_field = "world"
+        assert doc._get_changed_fields() == [
+            "db_embedded_field.db_list_field.2.db_string_field"
+        ]
+        assert doc.embedded_field._delta() == (
+            {"db_list_field.2.db_string_field": "world"},
+            {},
+        )
+        assert doc._delta() == (
+            {"db_embedded_field.db_list_field.2.db_string_field": "world"},
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].string_field == "world"
+
+        # Test multiple assignments
+        doc.embedded_field.list_field[2].string_field = "hello world"
+        doc.embedded_field.list_field[2] = doc.embedded_field.list_field[2]
+        assert doc._get_changed_fields() == ["db_embedded_field.db_list_field.2"]
+        assert doc.embedded_field._delta() == (
+            {
+                "db_list_field.2": {
+                    "_cls": "Embedded",
+                    "db_string_field": "hello world",
+                    "db_int_field": 1,
+                    "db_list_field": ["1", 2, {"hello": "world"}],
+                    "db_dict_field": {"hello": "world"},
+                }
+            },
+            {},
+        )
+        assert doc._delta() == (
+            {
+                "db_embedded_field.db_list_field.2": {
+                    "_cls": "Embedded",
+                    "db_string_field": "hello world",
+                    "db_int_field": 1,
+                    "db_list_field": ["1", 2, {"hello": "world"}],
+                    "db_dict_field": {"hello": "world"},
+                }
+            },
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].string_field == "hello world"
+
+        # Test list native methods
+        doc.embedded_field.list_field[2].list_field.pop(0)
+        assert doc._delta() == (
+            {
+                "db_embedded_field.db_list_field.2.db_list_field": [
+                    2,
+                    {"hello": "world"},
+                ]
+            },
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+
+        doc.embedded_field.list_field[2].list_field.append(1)
+        assert doc._delta() == (
+            {
+                "db_embedded_field.db_list_field.2.db_list_field": [
+                    2,
+                    {"hello": "world"},
+                    1,
+                ]
+            },
+            {},
+        )
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].list_field == [2, {"hello": "world"}, 1]
+
+        doc.embedded_field.list_field[2].list_field.sort(key=str)
+        doc.save()
+        doc = doc.reload(10)
+        assert doc.embedded_field.list_field[2].list_field == [1, 2, {"hello": "world"}]
+
+        del doc.embedded_field.list_field[2].list_field[2]["hello"]
+        assert doc._delta() == (
+            {},
+            {"db_embedded_field.db_list_field.2.db_list_field.2.hello": 1},
+        )
+        doc.save()
+        doc = doc.reload(10)
+
+        assert doc._delta() == ({}, {},)
+        del doc.embedded_field.list_field[2].list_field
+        assert doc._delta() == (
+            {},
+            {"db_embedded_field.db_list_field.2.db_list_field": 1},
+        )
+
+    def test_delta_for_dynamic_documents(self):
+        class Person(DynamicDocument):
+            name = StringField()
+            meta = {"allow_inheritance": True}
+
+        Person.drop_collection()
+
+        p = Person(name="James", age=34)
+        assert p._delta() == (
+            SON([("_cls", "Person"), ("name", "James"), ("age", 34)]),
+            {},
+        )
+
+        p.doc = 123
+        del p.doc
+        assert p._delta() == (
+            SON([("_cls", "Person"), ("name", "James"), ("age", 34)]),
+            {},
+        )
+
+        p = Person()
+        p.name = "Dean"
+        p.age = 22
+        p.save()
+
+        p.age = 24
+        assert p.age == 24
+        assert p._get_changed_fields() == ["age"]
+        assert p._delta() == ({"age": 24}, {})
+
+        p = Person.objects(age=22).get()
+        p.age = 24
+        assert p.age == 24
+        assert p._get_changed_fields() == ["age"]
+        assert p._delta() == ({"age": 24}, {})
+
+        p.save()
+        assert 1 == Person.objects(age=24).count()
+
+    def test_dynamic_delta(self):
+        class Doc(DynamicDocument):
+            pass
+
+        Doc.drop_collection()
+        doc = Doc()
+        doc.save()
+
+        doc = Doc.objects.first()
+        assert doc._get_changed_fields() == []
+        assert doc._delta() == ({}, {})
+
+        doc.string_field = "hello"
+        assert doc._get_changed_fields() == ["string_field"]
+        assert doc._delta() == ({"string_field": "hello"}, {})
+
+        doc._changed_fields = []
+        doc.int_field = 1
+        assert doc._get_changed_fields() == ["int_field"]
+        assert doc._delta() == ({"int_field": 1}, {})
+
+        doc._changed_fields = []
+        dict_value = {"hello": "world", "ping": "pong"}
+        doc.dict_field = dict_value
+        assert doc._get_changed_fields() == ["dict_field"]
+        assert doc._delta() == ({"dict_field": dict_value}, {})
+
+        doc._changed_fields = []
+        list_value = ["1", 2, {"hello": "world"}]
+        doc.list_field = list_value
+        assert doc._get_changed_fields() == ["list_field"]
+        assert doc._delta() == ({"list_field": list_value}, {})
+
+        # Test unsetting
+        doc._changed_fields = []
+        doc.dict_field = {}
+        assert doc._get_changed_fields() == ["dict_field"]
+        assert doc._delta() == ({}, {"dict_field": 1})
+
+        doc._changed_fields = []
+        doc.list_field = []
+        assert doc._get_changed_fields() == ["list_field"]
+        assert doc._delta() == ({}, {"list_field": 1})
+
+    def test_delta_with_dbref_true(self):
+        person, organization, employee = self.circular_reference_deltas_2(
+            Document, Document, True
+        )
+        employee.name = "test"
+
+        assert organization._get_changed_fields() == []
+
+        updates, removals = organization._delta()
+        assert removals == {}
+        assert updates == {}
+
+        organization.employees.append(person)
+        updates, removals = organization._delta()
+        assert removals == {}
+        assert "employees" in updates
+
+    def test_delta_with_dbref_false(self):
+        person, organization, employee = self.circular_reference_deltas_2(
+            Document, Document, False
+        )
+        employee.name = "test"
+
+        assert organization._get_changed_fields() == []
+
+        updates, removals = organization._delta()
+        assert removals == {}
+        assert updates == {}
+
+        organization.employees.append(person)
+        updates, removals = organization._delta()
+        assert removals == {}
+        assert "employees" in updates
+
+    def test_nested_nested_fields_mark_as_changed(self):
+        class EmbeddedDoc(EmbeddedDocument):
+            name = StringField()
+
+        class MyDoc(Document):
+            subs = MapField(MapField(EmbeddedDocumentField(EmbeddedDoc)))
+            name = StringField()
+
+        MyDoc.drop_collection()
+
+        mydoc = MyDoc(
+            name="testcase1", subs={"a": {"b": EmbeddedDoc(name="foo")}}
+        ).save()
+
+        mydoc = MyDoc.objects.first()
+        subdoc = mydoc.subs["a"]["b"]
+        subdoc.name = "bar"
+
+        assert subdoc._get_changed_fields() == ["name"]
+        assert mydoc._get_changed_fields() == ["subs.a.b.name"]
+
+        mydoc._clear_changed_fields()
+        assert mydoc._get_changed_fields() == []
+
+    def test_lower_level_mark_as_changed(self):
+        class EmbeddedDoc(EmbeddedDocument):
+            name = StringField()
+
+        class MyDoc(Document):
+            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
+
+        MyDoc.drop_collection()
+
+        MyDoc().save()
+
+        mydoc = MyDoc.objects.first()
+        mydoc.subs["a"] = EmbeddedDoc()
+        assert mydoc._get_changed_fields() == ["subs.a"]
+
+        subdoc = mydoc.subs["a"]
+        subdoc.name = "bar"
+
+        assert subdoc._get_changed_fields() == ["name"]
+        assert mydoc._get_changed_fields() == ["subs.a"]
+        mydoc.save()
+
+        mydoc._clear_changed_fields()
+        assert mydoc._get_changed_fields() == []
+
+    def test_upper_level_mark_as_changed(self):
+        class EmbeddedDoc(EmbeddedDocument):
+            name = StringField()
+
+        class MyDoc(Document):
+            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
+
+        MyDoc.drop_collection()
+
+        MyDoc(subs={"a": EmbeddedDoc(name="foo")}).save()
+
+        mydoc = MyDoc.objects.first()
+        subdoc = mydoc.subs["a"]
+        subdoc.name = "bar"
+
+        assert subdoc._get_changed_fields() == ["name"]
+        assert mydoc._get_changed_fields() == ["subs.a.name"]
+
+        mydoc.subs["a"] = EmbeddedDoc()
+        assert mydoc._get_changed_fields() == ["subs.a"]
+        mydoc.save()
+
+        mydoc._clear_changed_fields()
+        assert mydoc._get_changed_fields() == []
+
+    def test_referenced_object_changed_attributes(self):
+        """Ensures that when you save a new reference to a field, the referenced object isn't altered"""
+
+        class Organization(Document):
+            name = StringField()
+
+        class User(Document):
+            name = StringField()
+            org = ReferenceField("Organization", required=True)
+
+        Organization.drop_collection()
+        User.drop_collection()
+
+        org1 = Organization(name="Org 1")
+        org1.save()
+
+        org2 = Organization(name="Org 2")
+        org2.save()
+
+        user = User(name="Fred", org=org1)
+        user.save()
+
+        org1.reload()
+        org2.reload()
+        user.reload()
+        assert org1.name == "Org 1"
+        assert org2.name == "Org 2"
+        assert user.name == "Fred"
+
+        user.name = "Harold"
+        user.org = org2
+
+        org2.name = "New Org 2"
+        assert org2.name == "New Org 2"
+
+        user.save()
+        org2.save()
+
+        assert org2.name == "New Org 2"
+        org2.reload()
+        assert org2.name == "New Org 2"
+
+    def test_delta_for_nested_map_fields(self):
+        class UInfoDocument(Document):
+            phone = StringField()
+
+        class EmbeddedRole(EmbeddedDocument):
+            type = StringField()
+
+        class EmbeddedUser(EmbeddedDocument):
+            name = StringField()
+            roles = MapField(field=EmbeddedDocumentField(EmbeddedRole))
+            rolist = ListField(field=EmbeddedDocumentField(EmbeddedRole))
+            info = ReferenceField(UInfoDocument)
+
+        class Doc(Document):
+            users = MapField(field=EmbeddedDocumentField(EmbeddedUser))
+            num = IntField(default=-1)
+
+        Doc.drop_collection()
+
+        doc = Doc(num=1)
+        doc.users["007"] = EmbeddedUser(name="Agent007")
+        doc.save()
+
+        uinfo = UInfoDocument(phone="79089269066")
+        uinfo.save()
+
+        d = Doc.objects(num=1).first()
+        d.users["007"]["roles"]["666"] = EmbeddedRole(type="superadmin")
+        d.users["007"]["rolist"].append(EmbeddedRole(type="oops"))
+        d.users["007"]["info"] = uinfo
+        delta = d._delta()
+        assert True == ("users.007.roles.666" in delta[0])
+        assert True == ("users.007.rolist" in delta[0])
+        assert True == ("users.007.info" in delta[0])
+        assert "superadmin" == delta[0]["users.007.roles.666"]["type"]
+        assert "oops" == delta[0]["users.007.rolist"][0]["type"]
+        assert uinfo.id == delta[0]["users.007.info"]
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/document/test_dynamic.py

@@ -1,19 +1,20 @@
 import unittest
 
+import pytest
+
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 
-__all__ = ("TestDynamicDocument", )
+__all__ = ("TestDynamicDocument",)
 
 
 class TestDynamicDocument(MongoDBTestCase):
-
     def setUp(self):
         super(TestDynamicDocument, self).setUp()
 
         class Person(DynamicDocument):
             name = StringField()
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
         Person.drop_collection()
 
@@ -26,16 +27,15 @@ class TestDynamicDocument(MongoDBTestCase):
         p.name = "James"
         p.age = 34
 
-        self.assertEqual(p.to_mongo(), {"_cls": "Person", "name": "James",
+        assert p.to_mongo() == {"_cls": "Person", "name": "James", "age": 34}
-                                        "age": 34})
+        assert p.to_mongo().keys() == ["_cls", "name", "age"]
-        self.assertEqual(p.to_mongo().keys(), ["_cls", "name", "age"])
         p.save()
-        self.assertEqual(p.to_mongo().keys(), ["_id", "_cls", "name", "age"])
+        assert p.to_mongo().keys() == ["_id", "_cls", "name", "age"]
 
-        self.assertEqual(self.Person.objects.first().age, 34)
+        assert self.Person.objects.first().age == 34
 
         # Confirm no changes to self.Person
-        self.assertFalse(hasattr(self.Person, 'age'))
+        assert not hasattr(self.Person, "age")
 
     def test_change_scope_of_variable(self):
         """Test changing the scope of a dynamic field has no adverse effects"""
@@ -45,11 +45,11 @@ class TestDynamicDocument(MongoDBTestCase):
         p.save()
 
         p = self.Person.objects.get()
-        p.misc = {'hello': 'world'}
+        p.misc = {"hello": "world"}
         p.save()
 
         p = self.Person.objects.get()
-        self.assertEqual(p.misc, {'hello': 'world'})
+        assert p.misc == {"hello": "world"}
 
     def test_delete_dynamic_field(self):
         """Test deleting a dynamic field works"""
@@ -60,23 +60,23 @@ class TestDynamicDocument(MongoDBTestCase):
         p.save()
 
         p = self.Person.objects.get()
-        p.misc = {'hello': 'world'}
+        p.misc = {"hello": "world"}
         p.save()
 
         p = self.Person.objects.get()
-        self.assertEqual(p.misc, {'hello': 'world'})
+        assert p.misc == {"hello": "world"}
         collection = self.db[self.Person._get_collection_name()]
         obj = collection.find_one()
-        self.assertEqual(sorted(obj.keys()), ['_cls', '_id', 'misc', 'name'])
+        assert sorted(obj.keys()) == ["_cls", "_id", "misc", "name"]
 
         del p.misc
         p.save()
 
         p = self.Person.objects.get()
-        self.assertFalse(hasattr(p, 'misc'))
+        assert not hasattr(p, "misc")
 
         obj = collection.find_one()
-        self.assertEqual(sorted(obj.keys()), ['_cls', '_id', 'name'])
+        assert sorted(obj.keys()) == ["_cls", "_id", "name"]
 
     def test_reload_after_unsetting(self):
         p = self.Person()
@@ -90,78 +90,55 @@ class TestDynamicDocument(MongoDBTestCase):
         p = self.Person.objects.create()
         p.update(age=1)
 
-        self.assertEqual(len(p._data), 3)
+        assert len(p._data) == 3
-        self.assertEqual(sorted(p._data.keys()), ['_cls', 'id', 'name'])
+        assert sorted(p._data.keys()) == ["_cls", "id", "name"]
 
         p.reload()
-        self.assertEqual(len(p._data), 4)
+        assert len(p._data) == 4
-        self.assertEqual(sorted(p._data.keys()), ['_cls', 'age', 'id', 'name'])
+        assert sorted(p._data.keys()) == ["_cls", "age", "id", "name"]
 
     def test_fields_without_underscore(self):
         """Ensure we can query dynamic fields"""
         Person = self.Person
 
-        p = self.Person(name='Dean')
+        p = self.Person(name="Dean")
         p.save()
 
         raw_p = Person.objects.as_pymongo().get(id=p.id)
-        self.assertEqual(
+        assert raw_p == {"_cls": u"Person", "_id": p.id, "name": u"Dean"}
-            raw_p,
-            {
-                '_cls': u'Person',
-                '_id': p.id,
-                'name': u'Dean'
-             }
-        )
 
-        p.name = 'OldDean'
+        p.name = "OldDean"
-        p.newattr = 'garbage'
+        p.newattr = "garbage"
         p.save()
         raw_p = Person.objects.as_pymongo().get(id=p.id)
-        self.assertEqual(
+        assert raw_p == {
-            raw_p,
+            "_cls": u"Person",
-            {
+            "_id": p.id,
-                '_cls': u'Person',
+            "name": "OldDean",
-                '_id': p.id,
+            "newattr": u"garbage",
-                'name': 'OldDean',
+        }
-                'newattr': u'garbage'
-            }
-        )
 
     def test_fields_containing_underscore(self):
         """Ensure we can query dynamic fields"""
+
         class WeirdPerson(DynamicDocument):
             name = StringField()
             _name = StringField()
 
         WeirdPerson.drop_collection()
 
-        p = WeirdPerson(name='Dean', _name='Dean')
+        p = WeirdPerson(name="Dean", _name="Dean")
         p.save()
 
         raw_p = WeirdPerson.objects.as_pymongo().get(id=p.id)
-        self.assertEqual(
+        assert raw_p == {"_id": p.id, "_name": u"Dean", "name": u"Dean"}
-            raw_p,
-            {
-                '_id': p.id,
-                '_name': u'Dean',
-                'name': u'Dean'
-            }
-        )
 
-        p.name = 'OldDean'
+        p.name = "OldDean"
-        p._name = 'NewDean'
+        p._name = "NewDean"
-        p._newattr1 = 'garbage'    # Unknown fields won't be added
+        p._newattr1 = "garbage"  # Unknown fields won't be added
         p.save()
         raw_p = WeirdPerson.objects.as_pymongo().get(id=p.id)
-        self.assertEqual(
+        assert raw_p == {"_id": p.id, "_name": u"NewDean", "name": u"OldDean"}
-            raw_p,
-            {
-                '_id': p.id,
-                '_name': u'NewDean',
-                'name': u'OldDean',
-            }
-        )
 
     def test_dynamic_document_queries(self):
         """Ensure we can query dynamic fields"""
@@ -170,10 +147,10 @@ class TestDynamicDocument(MongoDBTestCase):
         p.age = 22
         p.save()
 
-        self.assertEqual(1, self.Person.objects(age=22).count())
+        assert 1 == self.Person.objects(age=22).count()
         p = self.Person.objects(age=22)
         p = p.get()
-        self.assertEqual(22, p.age)
+        assert 22 == p.age
 
     def test_complex_dynamic_document_queries(self):
         class Person(DynamicDocument):
@@ -193,26 +170,25 @@ class TestDynamicDocument(MongoDBTestCase):
         p2.age = 10
         p2.save()
 
-        self.assertEqual(Person.objects(age__icontains='ten').count(), 2)
+        assert Person.objects(age__icontains="ten").count() == 2
-        self.assertEqual(Person.objects(age__gte=10).count(), 1)
+        assert Person.objects(age__gte=10).count() == 1
 
     def test_complex_data_lookups(self):
         """Ensure you can query dynamic document dynamic fields"""
         p = self.Person()
-        p.misc = {'hello': 'world'}
+        p.misc = {"hello": "world"}
         p.save()
 
-        self.assertEqual(1, self.Person.objects(misc__hello='world').count())
+        assert 1 == self.Person.objects(misc__hello="world").count()
 
     def test_three_level_complex_data_lookups(self):
         """Ensure you can query three level document dynamic fields"""
-        p = self.Person.objects.create(
+        self.Person.objects.create(misc={"hello": {"hello2": "world"}})
-            misc={'hello': {'hello2': 'world'}}
+        assert 1 == self.Person.objects(misc__hello__hello2="world").count()
-        )
-        self.assertEqual(1, self.Person.objects(misc__hello__hello2='world').count())
 
     def test_complex_embedded_document_validation(self):
         """Ensure embedded dynamic documents may be validated"""
+
         class Embedded(DynamicEmbeddedDocument):
             content = URLField()
 
@@ -222,27 +198,29 @@ class TestDynamicDocument(MongoDBTestCase):
         Doc.drop_collection()
         doc = Doc()
 
-        embedded_doc_1 = Embedded(content='http://mongoengine.org')
+        embedded_doc_1 = Embedded(content="http://mongoengine.org")
         embedded_doc_1.validate()
 
-        embedded_doc_2 = Embedded(content='this is not a url')
+        embedded_doc_2 = Embedded(content="this is not a url")
-        self.assertRaises(ValidationError, embedded_doc_2.validate)
+        with pytest.raises(ValidationError):
+            embedded_doc_2.validate()
 
         doc.embedded_field_1 = embedded_doc_1
         doc.embedded_field_2 = embedded_doc_2
-        self.assertRaises(ValidationError, doc.validate)
+        with pytest.raises(ValidationError):
+            doc.validate()
 
     def test_inheritance(self):
         """Ensure that dynamic document plays nice with inheritance"""
+
         class Employee(self.Person):
             salary = IntField()
 
         Employee.drop_collection()
 
-        self.assertIn('name', Employee._fields)
+        assert "name" in Employee._fields
-        self.assertIn('salary', Employee._fields)
+        assert "salary" in Employee._fields
-        self.assertEqual(Employee._get_collection_name(),
+        assert Employee._get_collection_name() == self.Person._get_collection_name()
-                         self.Person._get_collection_name())
 
         joe_bloggs = Employee()
         joe_bloggs.name = "Joe Bloggs"
@@ -250,14 +228,15 @@ class TestDynamicDocument(MongoDBTestCase):
         joe_bloggs.age = 20
         joe_bloggs.save()
 
-        self.assertEqual(1, self.Person.objects(age=20).count())
+        assert 1 == self.Person.objects(age=20).count()
-        self.assertEqual(1, Employee.objects(age=20).count())
+        assert 1 == Employee.objects(age=20).count()
 
         joe_bloggs = self.Person.objects.first()
-        self.assertIsInstance(joe_bloggs, Employee)
+        assert isinstance(joe_bloggs, Employee)
 
     def test_embedded_dynamic_document(self):
         """Test dynamic embedded documents"""
+
         class Embedded(DynamicEmbeddedDocument):
             pass
 
@@ -268,33 +247,33 @@ class TestDynamicDocument(MongoDBTestCase):
         doc = Doc()
 
         embedded_1 = Embedded()
-        embedded_1.string_field = 'hello'
+        embedded_1.string_field = "hello"
         embedded_1.int_field = 1
-        embedded_1.dict_field = {'hello': 'world'}
+        embedded_1.dict_field = {"hello": "world"}
-        embedded_1.list_field = ['1', 2, {'hello': 'world'}]
+        embedded_1.list_field = ["1", 2, {"hello": "world"}]
         doc.embedded_field = embedded_1
 
-        self.assertEqual(doc.to_mongo(), {
+        assert doc.to_mongo() == {
             "embedded_field": {
                 "_cls": "Embedded",
                 "string_field": "hello",
                 "int_field": 1,
                 "dict_field": {"hello": "world"},
-                "list_field": ['1', 2, {'hello': 'world'}]
+                "list_field": ["1", 2, {"hello": "world"}],
             }
-        })
+        }
         doc.save()
 
         doc = Doc.objects.first()
-        self.assertEqual(doc.embedded_field.__class__, Embedded)
+        assert doc.embedded_field.__class__ == Embedded
-        self.assertEqual(doc.embedded_field.string_field, "hello")
+        assert doc.embedded_field.string_field == "hello"
-        self.assertEqual(doc.embedded_field.int_field, 1)
+        assert doc.embedded_field.int_field == 1
-        self.assertEqual(doc.embedded_field.dict_field, {'hello': 'world'})
+        assert doc.embedded_field.dict_field == {"hello": "world"}
-        self.assertEqual(doc.embedded_field.list_field,
+        assert doc.embedded_field.list_field == ["1", 2, {"hello": "world"}]
-                            ['1', 2, {'hello': 'world'}])
 
     def test_complex_embedded_documents(self):
         """Test complex dynamic embedded documents setups"""
+
         class Embedded(DynamicEmbeddedDocument):
             pass
 
@@ -305,51 +284,54 @@ class TestDynamicDocument(MongoDBTestCase):
         doc = Doc()
 
         embedded_1 = Embedded()
-        embedded_1.string_field = 'hello'
+        embedded_1.string_field = "hello"
         embedded_1.int_field = 1
-        embedded_1.dict_field = {'hello': 'world'}
+        embedded_1.dict_field = {"hello": "world"}
 
         embedded_2 = Embedded()
-        embedded_2.string_field = 'hello'
+        embedded_2.string_field = "hello"
         embedded_2.int_field = 1
-        embedded_2.dict_field = {'hello': 'world'}
+        embedded_2.dict_field = {"hello": "world"}
-        embedded_2.list_field = ['1', 2, {'hello': 'world'}]
+        embedded_2.list_field = ["1", 2, {"hello": "world"}]
 
-        embedded_1.list_field = ['1', 2, embedded_2]
+        embedded_1.list_field = ["1", 2, embedded_2]
         doc.embedded_field = embedded_1
 
-        self.assertEqual(doc.to_mongo(), {
+        assert doc.to_mongo() == {
             "embedded_field": {
                 "_cls": "Embedded",
                 "string_field": "hello",
                 "int_field": 1,
                 "dict_field": {"hello": "world"},
-                "list_field": ['1', 2,
+                "list_field": [
-                    {"_cls": "Embedded",
+                    "1",
-                    "string_field": "hello",
+                    2,
-                    "int_field": 1,
+                    {
-                    "dict_field": {"hello": "world"},
+                        "_cls": "Embedded",
-                    "list_field": ['1', 2, {'hello': 'world'}]}
+                        "string_field": "hello",
-                ]
+                        "int_field": 1,
+                        "dict_field": {"hello": "world"},
+                        "list_field": ["1", 2, {"hello": "world"}],
+                    },
+                ],
             }
-        })
+        }
         doc.save()
         doc = Doc.objects.first()
-        self.assertEqual(doc.embedded_field.__class__, Embedded)
+        assert doc.embedded_field.__class__ == Embedded
-        self.assertEqual(doc.embedded_field.string_field, "hello")
+        assert doc.embedded_field.string_field == "hello"
-        self.assertEqual(doc.embedded_field.int_field, 1)
+        assert doc.embedded_field.int_field == 1
-        self.assertEqual(doc.embedded_field.dict_field, {'hello': 'world'})
+        assert doc.embedded_field.dict_field == {"hello": "world"}
-        self.assertEqual(doc.embedded_field.list_field[0], '1')
+        assert doc.embedded_field.list_field[0] == "1"
-        self.assertEqual(doc.embedded_field.list_field[1], 2)
+        assert doc.embedded_field.list_field[1] == 2
 
         embedded_field = doc.embedded_field.list_field[2]
 
-        self.assertEqual(embedded_field.__class__, Embedded)
+        assert embedded_field.__class__ == Embedded
-        self.assertEqual(embedded_field.string_field, "hello")
+        assert embedded_field.string_field == "hello"
-        self.assertEqual(embedded_field.int_field, 1)
+        assert embedded_field.int_field == 1
-        self.assertEqual(embedded_field.dict_field, {'hello': 'world'})
+        assert embedded_field.dict_field == {"hello": "world"}
-        self.assertEqual(embedded_field.list_field, ['1', 2,
+        assert embedded_field.list_field == ["1", 2, {"hello": "world"}]
-                                                        {'hello': 'world'}])
 
     def test_dynamic_and_embedded(self):
         """Ensure embedded documents play nicely"""
@@ -368,18 +350,18 @@ class TestDynamicDocument(MongoDBTestCase):
         person.address.city = "Lundenne"
         person.save()
 
-        self.assertEqual(Person.objects.first().address.city, "Lundenne")
+        assert Person.objects.first().address.city == "Lundenne"
 
         person = Person.objects.first()
         person.address = Address(city="Londinium")
         person.save()
 
-        self.assertEqual(Person.objects.first().address.city, "Londinium")
+        assert Person.objects.first().address.city == "Londinium"
 
         person = Person.objects.first()
         person.age = 35
         person.save()
-        self.assertEqual(Person.objects.first().age, 35)
+        assert Person.objects.first().age == 35
 
     def test_dynamic_embedded_works_with_only(self):
         """Ensure custom fieldnames on a dynamic embedded document are found by qs.only()"""
@@ -392,10 +374,15 @@ class TestDynamicDocument(MongoDBTestCase):
 
         Person.drop_collection()
 
-        Person(name="Eric", address=Address(city="San Francisco", street_number="1337")).save()
+        Person(
+            name="Eric", address=Address(city="San Francisco", street_number="1337")
+        ).save()
 
-        self.assertEqual(Person.objects.first().address.street_number, '1337')
+        assert Person.objects.first().address.street_number == "1337"
-        self.assertEqual(Person.objects.only('address__street_number').first().address.street_number, '1337')
+        assert (
+            Person.objects.only("address__street_number").first().address.street_number
+            == "1337"
+        )
 
     def test_dynamic_and_embedded_dict_access(self):
         """Ensure embedded dynamic documents work with dict[] style access"""
@@ -419,21 +406,21 @@ class TestDynamicDocument(MongoDBTestCase):
         person["address"]["city"] = "Lundenne"
         person.save()
 
-        self.assertEqual(Person.objects.first().address.city, "Lundenne")
+        assert Person.objects.first().address.city == "Lundenne"
 
-        self.assertEqual(Person.objects.first().phone, "555-1212")
+        assert Person.objects.first().phone == "555-1212"
 
         person = Person.objects.first()
         person.address = Address(city="Londinium")
         person.save()
 
-        self.assertEqual(Person.objects.first().address.city, "Londinium")
+        assert Person.objects.first().address.city == "Londinium"
 
         person = Person.objects.first()
         person["age"] = 35
         person.save()
-        self.assertEqual(Person.objects.first().age, 35)
+        assert Person.objects.first().age == 35
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/document/test_inheritance.py

@@ -0,0 +1,631 @@
+# -*- coding: utf-8 -*-
+import unittest
+import warnings
+
+import pytest
+
+from mongoengine import (
+    BooleanField,
+    Document,
+    EmbeddedDocument,
+    EmbeddedDocumentField,
+    GenericReferenceField,
+    IntField,
+    ReferenceField,
+    StringField,
+)
+from mongoengine.pymongo_support import list_collection_names
+from tests.fixtures import Base
+from tests.utils import MongoDBTestCase
+
+
+class TestInheritance(MongoDBTestCase):
+    def tearDown(self):
+        for collection in list_collection_names(self.db):
+            self.db.drop_collection(collection)
+
+    def test_constructor_cls(self):
+        # Ensures _cls is properly set during construction
+        # and when object gets reloaded (prevent regression of #1950)
+        class EmbedData(EmbeddedDocument):
+            data = StringField()
+            meta = {"allow_inheritance": True}
+
+        class DataDoc(Document):
+            name = StringField()
+            embed = EmbeddedDocumentField(EmbedData)
+            meta = {"allow_inheritance": True}
+
+        test_doc = DataDoc(name="test", embed=EmbedData(data="data"))
+        assert test_doc._cls == "DataDoc"
+        assert test_doc.embed._cls == "EmbedData"
+        test_doc.save()
+        saved_doc = DataDoc.objects.with_id(test_doc.id)
+        assert test_doc._cls == saved_doc._cls
+        assert test_doc.embed._cls == saved_doc.embed._cls
+        test_doc.delete()
+
+    def test_superclasses(self):
+        """Ensure that the correct list of superclasses is assembled.
+        """
+
+        class Animal(Document):
+            meta = {"allow_inheritance": True}
+
+        class Fish(Animal):
+            pass
+
+        class Guppy(Fish):
+            pass
+
+        class Mammal(Animal):
+            pass
+
+        class Dog(Mammal):
+            pass
+
+        class Human(Mammal):
+            pass
+
+        assert Animal._superclasses == ()
+        assert Fish._superclasses == ("Animal",)
+        assert Guppy._superclasses == ("Animal", "Animal.Fish")
+        assert Mammal._superclasses == ("Animal",)
+        assert Dog._superclasses == ("Animal", "Animal.Mammal")
+        assert Human._superclasses == ("Animal", "Animal.Mammal")
+
+    def test_external_superclasses(self):
+        """Ensure that the correct list of super classes is assembled when
+        importing part of the model.
+        """
+
+        class Animal(Base):
+            pass
+
+        class Fish(Animal):
+            pass
+
+        class Guppy(Fish):
+            pass
+
+        class Mammal(Animal):
+            pass
+
+        class Dog(Mammal):
+            pass
+
+        class Human(Mammal):
+            pass
+
+        assert Animal._superclasses == ("Base",)
+        assert Fish._superclasses == ("Base", "Base.Animal")
+        assert Guppy._superclasses == ("Base", "Base.Animal", "Base.Animal.Fish")
+        assert Mammal._superclasses == ("Base", "Base.Animal")
+        assert Dog._superclasses == ("Base", "Base.Animal", "Base.Animal.Mammal")
+        assert Human._superclasses == ("Base", "Base.Animal", "Base.Animal.Mammal")
+
+    def test_subclasses(self):
+        """Ensure that the correct list of _subclasses (subclasses) is
+        assembled.
+        """
+
+        class Animal(Document):
+            meta = {"allow_inheritance": True}
+
+        class Fish(Animal):
+            pass
+
+        class Guppy(Fish):
+            pass
+
+        class Mammal(Animal):
+            pass
+
+        class Dog(Mammal):
+            pass
+
+        class Human(Mammal):
+            pass
+
+        assert Animal._subclasses == (
+            "Animal",
+            "Animal.Fish",
+            "Animal.Fish.Guppy",
+            "Animal.Mammal",
+            "Animal.Mammal.Dog",
+            "Animal.Mammal.Human",
+        )
+        assert Fish._subclasses == ("Animal.Fish", "Animal.Fish.Guppy")
+        assert Guppy._subclasses == ("Animal.Fish.Guppy",)
+        assert Mammal._subclasses == (
+            "Animal.Mammal",
+            "Animal.Mammal.Dog",
+            "Animal.Mammal.Human",
+        )
+        assert Human._subclasses == ("Animal.Mammal.Human",)
+
+    def test_external_subclasses(self):
+        """Ensure that the correct list of _subclasses (subclasses) is
+        assembled when importing part of the model.
+        """
+
+        class Animal(Base):
+            pass
+
+        class Fish(Animal):
+            pass
+
+        class Guppy(Fish):
+            pass
+
+        class Mammal(Animal):
+            pass
+
+        class Dog(Mammal):
+            pass
+
+        class Human(Mammal):
+            pass
+
+        assert Animal._subclasses == (
+            "Base.Animal",
+            "Base.Animal.Fish",
+            "Base.Animal.Fish.Guppy",
+            "Base.Animal.Mammal",
+            "Base.Animal.Mammal.Dog",
+            "Base.Animal.Mammal.Human",
+        )
+        assert Fish._subclasses == ("Base.Animal.Fish", "Base.Animal.Fish.Guppy")
+        assert Guppy._subclasses == ("Base.Animal.Fish.Guppy",)
+        assert Mammal._subclasses == (
+            "Base.Animal.Mammal",
+            "Base.Animal.Mammal.Dog",
+            "Base.Animal.Mammal.Human",
+        )
+        assert Human._subclasses == ("Base.Animal.Mammal.Human",)
+
+    def test_dynamic_declarations(self):
+        """Test that declaring an extra class updates meta data"""
+
+        class Animal(Document):
+            meta = {"allow_inheritance": True}
+
+        assert Animal._superclasses == ()
+        assert Animal._subclasses == ("Animal",)
+
+        # Test dynamically adding a class changes the meta data
+        class Fish(Animal):
+            pass
+
+        assert Animal._superclasses == ()
+        assert Animal._subclasses == ("Animal", "Animal.Fish")
+
+        assert Fish._superclasses == ("Animal",)
+        assert Fish._subclasses == ("Animal.Fish",)
+
+        # Test dynamically adding an inherited class changes the meta data
+        class Pike(Fish):
+            pass
+
+        assert Animal._superclasses == ()
+        assert Animal._subclasses == ("Animal", "Animal.Fish", "Animal.Fish.Pike")
+
+        assert Fish._superclasses == ("Animal",)
+        assert Fish._subclasses == ("Animal.Fish", "Animal.Fish.Pike")
+
+        assert Pike._superclasses == ("Animal", "Animal.Fish")
+        assert Pike._subclasses == ("Animal.Fish.Pike",)
+
+    def test_inheritance_meta_data(self):
+        """Ensure that document may inherit fields from a superclass document.
+        """
+
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+            meta = {"allow_inheritance": True}
+
+        class Employee(Person):
+            salary = IntField()
+
+        assert ["_cls", "age", "id", "name", "salary"] == sorted(
+            Employee._fields.keys()
+        )
+        assert Employee._get_collection_name() == Person._get_collection_name()
+
+    def test_inheritance_to_mongo_keys(self):
+        """Ensure that document may inherit fields from a superclass document.
+        """
+
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+            meta = {"allow_inheritance": True}
+
+        class Employee(Person):
+            salary = IntField()
+
+        assert ["_cls", "age", "id", "name", "salary"] == sorted(
+            Employee._fields.keys()
+        )
+        assert Person(name="Bob", age=35).to_mongo().keys() == ["_cls", "name", "age"]
+        assert Employee(name="Bob", age=35, salary=0).to_mongo().keys() == [
+            "_cls",
+            "name",
+            "age",
+            "salary",
+        ]
+        assert Employee._get_collection_name() == Person._get_collection_name()
+
+    def test_indexes_and_multiple_inheritance(self):
+        """ Ensure that all of the indexes are created for a document with
+        multiple inheritance.
+        """
+
+        class A(Document):
+            a = StringField()
+
+            meta = {"allow_inheritance": True, "indexes": ["a"]}
+
+        class B(Document):
+            b = StringField()
+
+            meta = {"allow_inheritance": True, "indexes": ["b"]}
+
+        class C(A, B):
+            pass
+
+        A.drop_collection()
+        B.drop_collection()
+        C.drop_collection()
+
+        C.ensure_indexes()
+
+        assert sorted(
+            [idx["key"] for idx in C._get_collection().index_information().values()]
+        ) == sorted(
+            [[(u"_cls", 1), (u"b", 1)], [(u"_id", 1)], [(u"_cls", 1), (u"a", 1)]]
+        )
+
+    def test_polymorphic_queries(self):
+        """Ensure that the correct subclasses are returned from a query
+        """
+
+        class Animal(Document):
+            meta = {"allow_inheritance": True}
+
+        class Fish(Animal):
+            pass
+
+        class Mammal(Animal):
+            pass
+
+        class Dog(Mammal):
+            pass
+
+        class Human(Mammal):
+            pass
+
+        Animal.drop_collection()
+
+        Animal().save()
+        Fish().save()
+        Mammal().save()
+        Dog().save()
+        Human().save()
+
+        classes = [obj.__class__ for obj in Animal.objects]
+        assert classes == [Animal, Fish, Mammal, Dog, Human]
+
+        classes = [obj.__class__ for obj in Mammal.objects]
+        assert classes == [Mammal, Dog, Human]
+
+        classes = [obj.__class__ for obj in Human.objects]
+        assert classes == [Human]
+
+    def test_allow_inheritance(self):
+        """Ensure that inheritance is disabled by default on simple
+        classes and that _cls will not be used.
+        """
+
+        class Animal(Document):
+            name = StringField()
+
+        # can't inherit because Animal didn't explicitly allow inheritance
+        with pytest.raises(ValueError, match="Document Animal may not be subclassed"):
+
+            class Dog(Animal):
+                pass
+
+        # Check that _cls etc aren't present on simple documents
+        dog = Animal(name="dog").save()
+        assert dog.to_mongo().keys() == ["_id", "name"]
+
+        collection = self.db[Animal._get_collection_name()]
+        obj = collection.find_one()
+        assert "_cls" not in obj
+
+    def test_cant_turn_off_inheritance_on_subclass(self):
+        """Ensure if inheritance is on in a subclass you cant turn it off.
+        """
+
+        class Animal(Document):
+            name = StringField()
+            meta = {"allow_inheritance": True}
+
+        with pytest.raises(ValueError) as exc_info:
+
+            class Mammal(Animal):
+                meta = {"allow_inheritance": False}
+
+        assert (
+            str(exc_info.value)
+            == 'Only direct subclasses of Document may set "allow_inheritance" to False'
+        )
+
+    def test_allow_inheritance_abstract_document(self):
+        """Ensure that abstract documents can set inheritance rules and that
+        _cls will not be used.
+        """
+
+        class FinalDocument(Document):
+            meta = {"abstract": True, "allow_inheritance": False}
+
+        class Animal(FinalDocument):
+            name = StringField()
+
+        with pytest.raises(ValueError):
+
+            class Mammal(Animal):
+                pass
+
+        # Check that _cls isn't present in simple documents
+        doc = Animal(name="dog")
+        assert "_cls" not in doc.to_mongo()
+
+    def test_using_abstract_class_in_reference_field(self):
+        # Ensures no regression of #1920
+        class AbstractHuman(Document):
+            meta = {"abstract": True}
+
+        class Dad(AbstractHuman):
+            name = StringField()
+
+        class Home(Document):
+            dad = ReferenceField(AbstractHuman)  # Referencing the abstract class
+            address = StringField()
+
+        dad = Dad(name="5").save()
+        Home(dad=dad, address="street").save()
+
+        home = Home.objects.first()
+        home.address = "garbage"
+        home.save()  # Was failing with ValidationError
+
+    def test_abstract_class_referencing_self(self):
+        # Ensures no regression of #1920
+        class Human(Document):
+            meta = {"abstract": True}
+            creator = ReferenceField("self", dbref=True)
+
+        class User(Human):
+            name = StringField()
+
+        user = User(name="John").save()
+        user2 = User(name="Foo", creator=user).save()
+
+        user2 = User.objects.with_id(user2.id)
+        user2.name = "Bar"
+        user2.save()  # Was failing with ValidationError
+
+    def test_abstract_handle_ids_in_metaclass_properly(self):
+        class City(Document):
+            continent = StringField()
+            meta = {"abstract": True, "allow_inheritance": False}
+
+        class EuropeanCity(City):
+            name = StringField()
+
+        berlin = EuropeanCity(name="Berlin", continent="Europe")
+        assert len(berlin._db_field_map) == len(berlin._fields_ordered)
+        assert len(berlin._reverse_db_field_map) == len(berlin._fields_ordered)
+        assert len(berlin._fields_ordered) == 3
+        assert berlin._fields_ordered[0] == "id"
+
+    def test_auto_id_not_set_if_specific_in_parent_class(self):
+        class City(Document):
+            continent = StringField()
+            city_id = IntField(primary_key=True)
+            meta = {"abstract": True, "allow_inheritance": False}
+
+        class EuropeanCity(City):
+            name = StringField()
+
+        berlin = EuropeanCity(name="Berlin", continent="Europe")
+        assert len(berlin._db_field_map) == len(berlin._fields_ordered)
+        assert len(berlin._reverse_db_field_map) == len(berlin._fields_ordered)
+        assert len(berlin._fields_ordered) == 3
+        assert berlin._fields_ordered[0] == "city_id"
+
+    def test_auto_id_vs_non_pk_id_field(self):
+        class City(Document):
+            continent = StringField()
+            id = IntField()
+            meta = {"abstract": True, "allow_inheritance": False}
+
+        class EuropeanCity(City):
+            name = StringField()
+
+        berlin = EuropeanCity(name="Berlin", continent="Europe")
+        assert len(berlin._db_field_map) == len(berlin._fields_ordered)
+        assert len(berlin._reverse_db_field_map) == len(berlin._fields_ordered)
+        assert len(berlin._fields_ordered) == 4
+        assert berlin._fields_ordered[0] == "auto_id_0"
+        berlin.save()
+        assert berlin.pk == berlin.auto_id_0
+
+    def test_abstract_document_creation_does_not_fail(self):
+        class City(Document):
+            continent = StringField()
+            meta = {"abstract": True, "allow_inheritance": False}
+
+        city = City(continent="asia")
+        assert city.pk is None
+        # TODO: expected error? Shouldn't we create a new error type?
+        with pytest.raises(KeyError):
+            setattr(city, "pk", 1)
+
+    def test_allow_inheritance_embedded_document(self):
+        """Ensure embedded documents respect inheritance."""
+
+        class Comment(EmbeddedDocument):
+            content = StringField()
+
+        with pytest.raises(ValueError):
+
+            class SpecialComment(Comment):
+                pass
+
+        doc = Comment(content="test")
+        assert "_cls" not in doc.to_mongo()
+
+        class Comment(EmbeddedDocument):
+            content = StringField()
+            meta = {"allow_inheritance": True}
+
+        doc = Comment(content="test")
+        assert "_cls" in doc.to_mongo()
+
+    def test_document_inheritance(self):
+        """Ensure mutliple inheritance of abstract documents
+        """
+
+        class DateCreatedDocument(Document):
+            meta = {"allow_inheritance": True, "abstract": True}
+
+        class DateUpdatedDocument(Document):
+            meta = {"allow_inheritance": True, "abstract": True}
+
+        try:
+
+            class MyDocument(DateCreatedDocument, DateUpdatedDocument):
+                pass
+
+        except Exception:
+            assert False, "Couldn't create MyDocument class"
+
+    def test_abstract_documents(self):
+        """Ensure that a document superclass can be marked as abstract
+        thereby not using it as the name for the collection."""
+
+        defaults = {
+            "index_background": True,
+            "index_opts": {"hello": "world"},
+            "allow_inheritance": True,
+            "queryset_class": "QuerySet",
+            "db_alias": "myDB",
+            "shard_key": ("hello", "world"),
+        }
+
+        meta_settings = {"abstract": True}
+        meta_settings.update(defaults)
+
+        class Animal(Document):
+            name = StringField()
+            meta = meta_settings
+
+        class Fish(Animal):
+            pass
+
+        class Guppy(Fish):
+            pass
+
+        class Mammal(Animal):
+            meta = {"abstract": True}
+
+        class Human(Mammal):
+            pass
+
+        for k, v in defaults.items():
+            for cls in [Animal, Fish, Guppy]:
+                assert cls._meta[k] == v
+
+        assert "collection" not in Animal._meta
+        assert "collection" not in Mammal._meta
+
+        assert Animal._get_collection_name() is None
+        assert Mammal._get_collection_name() is None
+
+        assert Fish._get_collection_name() == "fish"
+        assert Guppy._get_collection_name() == "fish"
+        assert Human._get_collection_name() == "human"
+
+        # ensure that a subclass of a non-abstract class can't be abstract
+        with pytest.raises(ValueError):
+
+            class EvilHuman(Human):
+                evil = BooleanField(default=True)
+                meta = {"abstract": True}
+
+    def test_abstract_embedded_documents(self):
+        # 789: EmbeddedDocument shouldn't inherit abstract
+        class A(EmbeddedDocument):
+            meta = {"abstract": True}
+
+        class B(A):
+            pass
+
+        assert not B._meta["abstract"]
+
+    def test_inherited_collections(self):
+        """Ensure that subclassed documents don't override parents'
+        collections
+        """
+
+        class Drink(Document):
+            name = StringField()
+            meta = {"allow_inheritance": True}
+
+        class Drinker(Document):
+            drink = GenericReferenceField()
+
+        try:
+            warnings.simplefilter("error")
+
+            class AcloholicDrink(Drink):
+                meta = {"collection": "booze"}
+
+        except SyntaxWarning:
+            warnings.simplefilter("ignore")
+
+            class AlcoholicDrink(Drink):
+                meta = {"collection": "booze"}
+
+        else:
+            raise AssertionError("SyntaxWarning should be triggered")
+
+        warnings.resetwarnings()
+
+        Drink.drop_collection()
+        AlcoholicDrink.drop_collection()
+        Drinker.drop_collection()
+
+        red_bull = Drink(name="Red Bull")
+        red_bull.save()
+
+        programmer = Drinker(drink=red_bull)
+        programmer.save()
+
+        beer = AlcoholicDrink(name="Beer")
+        beer.save()
+        real_person = Drinker(drink=beer)
+        real_person.save()
+
+        assert Drinker.objects[0].drink.name == red_bull.name
+        assert Drinker.objects[1].drink.name == beer.name
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/document/test_json_serialisation.py

@@ -1,22 +1,14 @@
 import unittest
 import uuid
 
-from nose.plugins.skip import SkipTest
 from datetime import datetime
 from bson import ObjectId
 
-import pymongo
-
 from mongoengine import *
-
+from tests.utils import MongoDBTestCase
-__all__ = ("TestJson",)
 
 
-class TestJson(unittest.TestCase):
+class TestJson(MongoDBTestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-
     def test_json_names(self):
         """
         Going to test reported issue:
@@ -25,22 +17,24 @@ class TestJson(unittest.TestCase):
         a to_json with the original class names and not the abreviated
         mongodb document keys
         """
+
         class Embedded(EmbeddedDocument):
-            string = StringField(db_field='s')
+            string = StringField(db_field="s")
 
         class Doc(Document):
-            string = StringField(db_field='s')
+            string = StringField(db_field="s")
-            embedded = EmbeddedDocumentField(Embedded, db_field='e')
+            embedded = EmbeddedDocumentField(Embedded, db_field="e")
 
         doc = Doc(string="Hello", embedded=Embedded(string="Inner Hello"))
-        doc_json = doc.to_json(sort_keys=True, use_db_field=False, separators=(',', ':'))
+        doc_json = doc.to_json(
+            sort_keys=True, use_db_field=False, separators=(",", ":")
+        )
 
         expected_json = """{"embedded":{"string":"Inner Hello"},"string":"Hello"}"""
 
-        self.assertEqual(doc_json, expected_json)
+        assert doc_json == expected_json
 
     def test_json_simple(self):
-
         class Embedded(EmbeddedDocument):
             string = StringField()
 
@@ -49,16 +43,18 @@ class TestJson(unittest.TestCase):
             embedded_field = EmbeddedDocumentField(Embedded)
 
             def __eq__(self, other):
-                return (self.string == other.string and
+                return (
-                        self.embedded_field == other.embedded_field)
+                    self.string == other.string
+                    and self.embedded_field == other.embedded_field
+                )
 
         doc = Doc(string="Hi", embedded_field=Embedded(string="Hi"))
 
-        doc_json = doc.to_json(sort_keys=True, separators=(',', ':'))
+        doc_json = doc.to_json(sort_keys=True, separators=(",", ":"))
         expected_json = """{"embedded_field":{"string":"Hi"},"string":"Hi"}"""
-        self.assertEqual(doc_json, expected_json)
+        assert doc_json == expected_json
 
-        self.assertEqual(doc, Doc.from_json(doc.to_json()))
+        assert doc == Doc.from_json(doc.to_json())
 
     def test_json_complex(self):
         class EmbeddedDoc(EmbeddedDocument):
@@ -68,41 +64,43 @@ class TestJson(unittest.TestCase):
             pass
 
         class Doc(Document):
-            string_field = StringField(default='1')
+            string_field = StringField(default="1")
             int_field = IntField(default=1)
             float_field = FloatField(default=1.1)
             boolean_field = BooleanField(default=True)
             datetime_field = DateTimeField(default=datetime.now)
-            embedded_document_field = EmbeddedDocumentField(EmbeddedDoc,
+            embedded_document_field = EmbeddedDocumentField(
-                                        default=lambda: EmbeddedDoc())
+                EmbeddedDoc, default=lambda: EmbeddedDoc()
+            )
             list_field = ListField(default=lambda: [1, 2, 3])
             dict_field = DictField(default=lambda: {"hello": "world"})
             objectid_field = ObjectIdField(default=ObjectId)
-            reference_field = ReferenceField(Simple, default=lambda:
+            reference_field = ReferenceField(Simple, default=lambda: Simple().save())
-                                                        Simple().save())
             map_field = MapField(IntField(), default=lambda: {"simple": 1})
             decimal_field = DecimalField(default=1.0)
             complex_datetime_field = ComplexDateTimeField(default=datetime.now)
             url_field = URLField(default="http://mongoengine.org")
             dynamic_field = DynamicField(default=1)
             generic_reference_field = GenericReferenceField(
-                                            default=lambda: Simple().save())
+                default=lambda: Simple().save()
-            sorted_list_field = SortedListField(IntField(),
+            )
-                                                default=lambda: [1, 2, 3])
+            sorted_list_field = SortedListField(IntField(), default=lambda: [1, 2, 3])
             email_field = EmailField(default="ross@example.com")
             geo_point_field = GeoPointField(default=lambda: [1, 2])
             sequence_field = SequenceField()
             uuid_field = UUIDField(default=uuid.uuid4)
             generic_embedded_document_field = GenericEmbeddedDocumentField(
-                                        default=lambda: EmbeddedDoc())
+                default=lambda: EmbeddedDoc()
+            )
 
             def __eq__(self, other):
                 import json
+
                 return json.loads(self.to_json()) == json.loads(other.to_json())
 
         doc = Doc()
-        self.assertEqual(doc, Doc.from_json(doc.to_json()))
+        assert doc == Doc.from_json(doc.to_json())
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/document/test_validation.py

@@ -2,55 +2,60 @@
 import unittest
 from datetime import datetime
 
+import pytest
+
 from mongoengine import *
-
+from tests.utils import MongoDBTestCase
-__all__ = ("ValidatorErrorTest",)
 
 
-class ValidatorErrorTest(unittest.TestCase):
+class TestValidatorError(MongoDBTestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-
     def test_to_dict(self):
         """Ensure a ValidationError handles error to_dict correctly.
         """
-        error = ValidationError('root')
+        error = ValidationError("root")
-        self.assertEqual(error.to_dict(), {})
+        assert error.to_dict() == {}
 
         # 1st level error schema
-        error.errors = {'1st': ValidationError('bad 1st'), }
+        error.errors = {"1st": ValidationError("bad 1st")}
-        self.assertIn('1st', error.to_dict())
+        assert "1st" in error.to_dict()
-        self.assertEqual(error.to_dict()['1st'], 'bad 1st')
+        assert error.to_dict()["1st"] == "bad 1st"
 
         # 2nd level error schema
-        error.errors = {'1st': ValidationError('bad 1st', errors={
+        error.errors = {
-            '2nd': ValidationError('bad 2nd'),
+            "1st": ValidationError(
-        })}
+                "bad 1st", errors={"2nd": ValidationError("bad 2nd")}
-        self.assertIn('1st', error.to_dict())
+            )
-        self.assertIsInstance(error.to_dict()['1st'], dict)
+        }
-        self.assertIn('2nd', error.to_dict()['1st'])
+        assert "1st" in error.to_dict()
-        self.assertEqual(error.to_dict()['1st']['2nd'], 'bad 2nd')
+        assert isinstance(error.to_dict()["1st"], dict)
+        assert "2nd" in error.to_dict()["1st"]
+        assert error.to_dict()["1st"]["2nd"] == "bad 2nd"
 
         # moar levels
-        error.errors = {'1st': ValidationError('bad 1st', errors={
+        error.errors = {
-            '2nd': ValidationError('bad 2nd', errors={
+            "1st": ValidationError(
-                '3rd': ValidationError('bad 3rd', errors={
+                "bad 1st",
-                    '4th': ValidationError('Inception'),
+                errors={
-                }),
+                    "2nd": ValidationError(
-            }),
+                        "bad 2nd",
-        })}
+                        errors={
-        self.assertIn('1st', error.to_dict())
+                            "3rd": ValidationError(
-        self.assertIn('2nd', error.to_dict()['1st'])
+                                "bad 3rd", errors={"4th": ValidationError("Inception")}
-        self.assertIn('3rd', error.to_dict()['1st']['2nd'])
+                            )
-        self.assertIn('4th', error.to_dict()['1st']['2nd']['3rd'])
+                        },
-        self.assertEqual(error.to_dict()['1st']['2nd']['3rd']['4th'],
+                    )
-                         'Inception')
+                },
+            )
+        }
+        assert "1st" in error.to_dict()
+        assert "2nd" in error.to_dict()["1st"]
+        assert "3rd" in error.to_dict()["1st"]["2nd"]
+        assert "4th" in error.to_dict()["1st"]["2nd"]["3rd"]
+        assert error.to_dict()["1st"]["2nd"]["3rd"]["4th"] == "Inception"
 
-        self.assertEqual(error.message, "root(2nd.3rd.4th.Inception: ['1st'])")
+        assert error.message == "root(2nd.3rd.4th.Inception: ['1st'])"
 
     def test_model_validation(self):
-
         class User(Document):
             username = StringField(primary_key=True)
             name = StringField(required=True)
@@ -58,67 +63,69 @@ class ValidatorErrorTest(unittest.TestCase):
         try:
             User().validate()
         except ValidationError as e:
-            self.assertIn("User:None", e.message)
+            assert "User:None" in e.message
-            self.assertEqual(e.to_dict(), {
+            assert e.to_dict() == {
-                'username': 'Field is required',
+                "username": "Field is required",
-                'name': 'Field is required'})
+                "name": "Field is required",
+            }
 
         user = User(username="RossC0", name="Ross").save()
         user.name = None
         try:
             user.save()
         except ValidationError as e:
-            self.assertIn("User:RossC0", e.message)
+            assert "User:RossC0" in e.message
-            self.assertEqual(e.to_dict(), {
+            assert e.to_dict() == {"name": "Field is required"}
-                'name': 'Field is required'})
 
     def test_fields_rewrite(self):
         class BasePerson(Document):
             name = StringField()
             age = IntField()
-            meta = {'abstract': True}
+            meta = {"abstract": True}
 
         class Person(BasePerson):
             name = StringField(required=True)
 
         p = Person(age=15)
-        self.assertRaises(ValidationError, p.validate)
+        with pytest.raises(ValidationError):
+            p.validate()
 
     def test_embedded_document_validation(self):
         """Ensure that embedded documents may be validated.
         """
+
         class Comment(EmbeddedDocument):
             date = DateTimeField()
             content = StringField(required=True)
 
         comment = Comment()
-        self.assertRaises(ValidationError, comment.validate)
+        with pytest.raises(ValidationError):
+            comment.validate()
 
-        comment.content = 'test'
+        comment.content = "test"
         comment.validate()
 
         comment.date = 4
-        self.assertRaises(ValidationError, comment.validate)
+        with pytest.raises(ValidationError):
+            comment.validate()
 
         comment.date = datetime.now()
         comment.validate()
-        self.assertEqual(comment._instance, None)
+        assert comment._instance is None
 
     def test_embedded_db_field_validate(self):
-
         class SubDoc(EmbeddedDocument):
             val = IntField(required=True)
 
         class Doc(Document):
             id = StringField(primary_key=True)
-            e = EmbeddedDocumentField(SubDoc, db_field='eb')
+            e = EmbeddedDocumentField(SubDoc, db_field="eb")
 
         try:
             Doc(id="bad").validate()
         except ValidationError as e:
-            self.assertIn("SubDoc:None", e.message)
+            assert "SubDoc:None" in e.message
-            self.assertEqual(e.to_dict(), {
+            assert e.to_dict() == {"e": {"val": "OK could not be converted to int"}}
-                "e": {'val': 'OK could not be converted to int'}})
 
         Doc.drop_collection()
 
@@ -126,25 +133,23 @@ class ValidatorErrorTest(unittest.TestCase):
 
         doc = Doc.objects.first()
         keys = doc._data.keys()
-        self.assertEqual(2, len(keys))
+        assert 2 == len(keys)
-        self.assertIn('e', keys)
+        assert "e" in keys
-        self.assertIn('id', keys)
+        assert "id" in keys
 
         doc.e.val = "OK"
         try:
             doc.save()
         except ValidationError as e:
-            self.assertIn("Doc:test", e.message)
+            assert "Doc:test" in e.message
-            self.assertEqual(e.to_dict(), {
+            assert e.to_dict() == {"e": {"val": "OK could not be converted to int"}}
-                "e": {'val': 'OK could not be converted to int'}})
 
     def test_embedded_weakref(self):
-
         class SubDoc(EmbeddedDocument):
             val = IntField(required=True)
 
         class Doc(Document):
-            e = EmbeddedDocumentField(SubDoc, db_field='eb')
+            e = EmbeddedDocumentField(SubDoc, db_field="eb")
 
         Doc.drop_collection()
 
@@ -153,23 +158,26 @@ class ValidatorErrorTest(unittest.TestCase):
 
         s = SubDoc()
 
-        self.assertRaises(ValidationError, s.validate)
+        with pytest.raises(ValidationError):
+            s.validate()
 
         d1.e = s
         d2.e = s
 
         del d1
 
-        self.assertRaises(ValidationError, d2.validate)
+        with pytest.raises(ValidationError):
+            d2.validate()
 
     def test_parent_reference_in_child_document(self):
         """
         Test to ensure a ReferenceField can store a reference to a parent
         class when inherited. Issue #954.
         """
+
         class Parent(Document):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
-            reference = ReferenceField('self')
+            reference = ReferenceField("self")
 
         class Child(Parent):
             pass
@@ -190,9 +198,10 @@ class ValidatorErrorTest(unittest.TestCase):
         Test to ensure a ReferenceField can store a reference to a parent
         class when inherited and when set via attribute. Issue #954.
         """
+
         class Parent(Document):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
-            reference = ReferenceField('self')
+            reference = ReferenceField("self")
 
         class Child(Parent):
             pass
@@ -210,5 +219,5 @@ class ValidatorErrorTest(unittest.TestCase):
             self.fail("ValidationError raised: %s" % e.message)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/fields/__init__.py

@@ -1,3 +0,0 @@
-from .fields import *
-from .file_tests import *
-from .geo import *

tests/fields/test_binary_field.py

@@ -1,27 +1,28 @@
 # -*- coding: utf-8 -*-
 import uuid
 
-from nose.plugins.skip import SkipTest
-import six
-
 from bson import Binary
+import pytest
 
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 
-BIN_VALUE = six.b('\xa9\xf3\x8d(\xd7\x03\x84\xb4k[\x0f\xe3\xa2\x19\x85p[J\xa3\xd2>\xde\xe6\x87\xb1\x7f\xc6\xe6\xd9r\x18\xf5')
+BIN_VALUE = "\xa9\xf3\x8d(\xd7\x03\x84\xb4k[\x0f\xe3\xa2\x19\x85p[J\xa3\xd2>\xde\xe6\x87\xb1\x7f\xc6\xe6\xd9r\x18\xf5".encode(
+    "latin-1"
+)
 
 
 class TestBinaryField(MongoDBTestCase):
     def test_binary_fields(self):
         """Ensure that binary fields can be stored and retrieved.
         """
+
         class Attachment(Document):
             content_type = StringField()
             blob = BinaryField()
 
-        BLOB = six.b('\xe6\x00\xc4\xff\x07')
+        BLOB = "\xe6\x00\xc4\xff\x07".encode("latin-1")
-        MIME_TYPE = 'application/octet-stream'
+        MIME_TYPE = "application/octet-stream"
 
         Attachment.drop_collection()
 
@@ -29,12 +30,13 @@ class TestBinaryField(MongoDBTestCase):
         attachment.save()
 
         attachment_1 = Attachment.objects().first()
-        self.assertEqual(MIME_TYPE, attachment_1.content_type)
+        assert MIME_TYPE == attachment_1.content_type
-        self.assertEqual(BLOB, six.binary_type(attachment_1.blob))
+        assert BLOB == bytes(attachment_1.blob)
 
     def test_validation_succeeds(self):
         """Ensure that valid values can be assigned to binary fields.
         """
+
         class AttachmentRequired(Document):
             blob = BinaryField(required=True)
 
@@ -42,13 +44,15 @@ class TestBinaryField(MongoDBTestCase):
             blob = BinaryField(max_bytes=4)
 
         attachment_required = AttachmentRequired()
-        self.assertRaises(ValidationError, attachment_required.validate)
+        with pytest.raises(ValidationError):
-        attachment_required.blob = Binary(six.b('\xe6\x00\xc4\xff\x07'))
+            attachment_required.validate()
+        attachment_required.blob = Binary("\xe6\x00\xc4\xff\x07".encode("latin-1"))
         attachment_required.validate()
 
-        _5_BYTES = six.b('\xe6\x00\xc4\xff\x07')
+        _5_BYTES = "\xe6\x00\xc4\xff\x07".encode("latin-1")
-        _4_BYTES = six.b('\xe6\x00\xc4\xff')
+        _4_BYTES = "\xe6\x00\xc4\xff".encode("latin-1")
-        self.assertRaises(ValidationError, AttachmentSizeLimit(blob=_5_BYTES).validate)
+        with pytest.raises(ValidationError):
+            AttachmentSizeLimit(blob=_5_BYTES).validate()
         AttachmentSizeLimit(blob=_4_BYTES).validate()
 
     def test_validation_fails(self):
@@ -57,8 +61,9 @@ class TestBinaryField(MongoDBTestCase):
         class Attachment(Document):
             blob = BinaryField()
 
-        for invalid_data in (2, u'Im_a_unicode', ['some_str']):
+        for invalid_data in (2, u"Im_a_unicode", ["some_str"]):
-            self.assertRaises(ValidationError, Attachment(blob=invalid_data).validate)
+            with pytest.raises(ValidationError):
+                Attachment(blob=invalid_data).validate()
 
     def test__primary(self):
         class Attachment(Document):
@@ -67,23 +72,21 @@ class TestBinaryField(MongoDBTestCase):
         Attachment.drop_collection()
         binary_id = uuid.uuid4().bytes
         att = Attachment(id=binary_id).save()
-        self.assertEqual(1, Attachment.objects.count())
+        assert 1 == Attachment.objects.count()
-        self.assertEqual(1, Attachment.objects.filter(id=att.id).count())
+        assert 1 == Attachment.objects.filter(id=att.id).count()
         att.delete()
-        self.assertEqual(0, Attachment.objects.count())
+        assert 0 == Attachment.objects.count()
 
     def test_primary_filter_by_binary_pk_as_str(self):
-        raise SkipTest("Querying by id as string is not currently supported")
-
         class Attachment(Document):
             id = BinaryField(primary_key=True)
 
         Attachment.drop_collection()
         binary_id = uuid.uuid4().bytes
         att = Attachment(id=binary_id).save()
-        self.assertEqual(1, Attachment.objects.filter(id=binary_id).count())
+        assert 1 == Attachment.objects.filter(id=binary_id).count()
         att.delete()
-        self.assertEqual(0, Attachment.objects.count())
+        assert 0 == Attachment.objects.count()
 
     def test_match_querying_with_bytes(self):
         class MyDocument(Document):
@@ -93,7 +96,7 @@ class TestBinaryField(MongoDBTestCase):
 
         doc = MyDocument(bin_field=BIN_VALUE).save()
         matched_doc = MyDocument.objects(bin_field=BIN_VALUE).first()
-        self.assertEqual(matched_doc.id, doc.id)
+        assert matched_doc.id == doc.id
 
     def test_match_querying_with_binary(self):
         class MyDocument(Document):
@@ -104,40 +107,37 @@ class TestBinaryField(MongoDBTestCase):
         doc = MyDocument(bin_field=BIN_VALUE).save()
 
         matched_doc = MyDocument.objects(bin_field=Binary(BIN_VALUE)).first()
-        self.assertEqual(matched_doc.id, doc.id)
+        assert matched_doc.id == doc.id
 
     def test_modify_operation__set(self):
         """Ensures no regression of bug #1127"""
+
         class MyDocument(Document):
             some_field = StringField()
             bin_field = BinaryField()
 
         MyDocument.drop_collection()
 
-        doc = MyDocument.objects(some_field='test').modify(
+        doc = MyDocument.objects(some_field="test").modify(
-            upsert=True, new=True,
+            upsert=True, new=True, set__bin_field=BIN_VALUE
-            set__bin_field=BIN_VALUE
         )
-        self.assertEqual(doc.some_field, 'test')
+        assert doc.some_field == "test"
-        if six.PY3:
+        assert doc.bin_field == BIN_VALUE
-            self.assertEqual(doc.bin_field, BIN_VALUE)
-        else:
-            self.assertEqual(doc.bin_field, Binary(BIN_VALUE))
 
     def test_update_one(self):
         """Ensures no regression of bug #1127"""
+
         class MyDocument(Document):
             bin_field = BinaryField()
 
         MyDocument.drop_collection()
 
-        bin_data = six.b('\xe6\x00\xc4\xff\x07')
+        bin_data = "\xe6\x00\xc4\xff\x07".encode("latin-1")
         doc = MyDocument(bin_field=bin_data).save()
 
-        n_updated = MyDocument.objects(bin_field=bin_data).update_one(bin_field=BIN_VALUE)
+        n_updated = MyDocument.objects(bin_field=bin_data).update_one(
-        self.assertEqual(n_updated, 1)
+            bin_field=BIN_VALUE
+        )
+        assert n_updated == 1
         fetched = MyDocument.objects.with_id(doc.id)
-        if six.PY3:
+        assert fetched.bin_field == BIN_VALUE
-            self.assertEqual(fetched.bin_field, BIN_VALUE)
-        else:
-            self.assertEqual(fetched.bin_field, Binary(BIN_VALUE))

tests/fields/test_boolean_field.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
-from mongoengine import *
+import pytest
 
+from mongoengine import *
 from tests.utils import MongoDBTestCase, get_as_pymongo
 
 
@@ -11,15 +12,13 @@ class TestBooleanField(MongoDBTestCase):
 
         person = Person(admin=True)
         person.save()
-        self.assertEqual(
+        assert get_as_pymongo(person) == {"_id": person.id, "admin": True}
-            get_as_pymongo(person),
-            {'_id': person.id,
-             'admin': True})
 
     def test_validation(self):
         """Ensure that invalid values cannot be assigned to boolean
         fields.
         """
+
         class Person(Document):
             admin = BooleanField()
 
@@ -28,22 +27,26 @@ class TestBooleanField(MongoDBTestCase):
         person.validate()
 
         person.admin = 2
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
-        person.admin = 'Yes'
+            person.validate()
-        self.assertRaises(ValidationError, person.validate)
+        person.admin = "Yes"
-        person.admin = 'False'
+        with pytest.raises(ValidationError):
-        self.assertRaises(ValidationError, person.validate)
+            person.validate()
+        person.admin = "False"
+        with pytest.raises(ValidationError):
+            person.validate()
 
     def test_weirdness_constructor(self):
         """When attribute is set in contructor, it gets cast into a bool
         which causes some weird behavior. We dont necessarily want to maintain this behavior
         but its a known issue
         """
+
         class Person(Document):
             admin = BooleanField()
 
-        new_person = Person(admin='False')
+        new_person = Person(admin="False")
-        self.assertTrue(new_person.admin)
+        assert new_person.admin
 
-        new_person = Person(admin='0')
+        new_person = Person(admin="0")
-        self.assertTrue(new_person.admin)
+        assert new_person.admin

tests/fields/test_cached_reference_field.py

@@ -1,18 +1,19 @@
 # -*- coding: utf-8 -*-
 from decimal import Decimal
 
-from mongoengine import *
+import pytest
 
+from mongoengine import *
 from tests.utils import MongoDBTestCase
 
 
 class TestCachedReferenceField(MongoDBTestCase):
-
     def test_get_and_save(self):
         """
         Tests #1047: CachedReferenceField creates DBRefs on to_python,
         but can't save them on to_mongo.
         """
+
         class Animal(Document):
             name = StringField()
             tag = StringField()
@@ -24,10 +25,11 @@ class TestCachedReferenceField(MongoDBTestCase):
         Animal.drop_collection()
         Ocorrence.drop_collection()
 
-        Ocorrence(person="testte",
+        Ocorrence(
-                  animal=Animal(name="Leopard", tag="heavy").save()).save()
+            person="testte", animal=Animal(name="Leopard", tag="heavy").save()
+        ).save()
         p = Ocorrence.objects.get()
-        p.person = 'new_testte'
+        p.person = "new_testte"
         p.save()
 
     def test_general_things(self):
@@ -37,8 +39,7 @@ class TestCachedReferenceField(MongoDBTestCase):
 
         class Ocorrence(Document):
             person = StringField()
-            animal = CachedReferenceField(
+            animal = CachedReferenceField(Animal, fields=["tag"])
-                Animal, fields=['tag'])
 
         Animal.drop_collection()
         Ocorrence.drop_collection()
@@ -46,30 +47,29 @@ class TestCachedReferenceField(MongoDBTestCase):
         a = Animal(name="Leopard", tag="heavy")
         a.save()
 
-        self.assertEqual(Animal._cached_reference_fields, [Ocorrence.animal])
+        assert Animal._cached_reference_fields == [Ocorrence.animal]
         o = Ocorrence(person="teste", animal=a)
         o.save()
 
         p = Ocorrence(person="Wilson")
         p.save()
 
-        self.assertEqual(Ocorrence.objects(animal=None).count(), 1)
+        assert Ocorrence.objects(animal=None).count() == 1
 
-        self.assertEqual(
+        assert a.to_mongo(fields=["tag"]) == {"tag": "heavy", "_id": a.pk}
-            a.to_mongo(fields=['tag']), {'tag': 'heavy', "_id": a.pk})
 
-        self.assertEqual(o.to_mongo()['animal']['tag'], 'heavy')
+        assert o.to_mongo()["animal"]["tag"] == "heavy"
 
         # counts
         Ocorrence(person="teste 2").save()
         Ocorrence(person="teste 3").save()
 
-        count = Ocorrence.objects(animal__tag='heavy').count()
+        count = Ocorrence.objects(animal__tag="heavy").count()
-        self.assertEqual(count, 1)
+        assert count == 1
 
-        ocorrence = Ocorrence.objects(animal__tag='heavy').first()
+        ocorrence = Ocorrence.objects(animal__tag="heavy").first()
-        self.assertEqual(ocorrence.person, "teste")
+        assert ocorrence.person == "teste"
-        self.assertIsInstance(ocorrence.animal, Animal)
+        assert isinstance(ocorrence.animal, Animal)
 
     def test_with_decimal(self):
         class PersonAuto(Document):
@@ -78,28 +78,22 @@ class TestCachedReferenceField(MongoDBTestCase):
 
         class SocialTest(Document):
             group = StringField()
-            person = CachedReferenceField(
+            person = CachedReferenceField(PersonAuto, fields=("salary",))
-                PersonAuto,
-                fields=('salary',))
 
         PersonAuto.drop_collection()
         SocialTest.drop_collection()
 
-        p = PersonAuto(name="Alberto", salary=Decimal('7000.00'))
+        p = PersonAuto(name="Alberto", salary=Decimal("7000.00"))
         p.save()
 
         s = SocialTest(group="dev", person=p)
         s.save()
 
-        self.assertEqual(
+        assert SocialTest.objects._collection.find_one({"person.salary": 7000.00}) == {
-            SocialTest.objects._collection.find_one({'person.salary': 7000.00}), {
+            "_id": s.pk,
-                '_id': s.pk,
+            "group": s.group,
-                'group': s.group,
+            "person": {"_id": p.pk, "salary": 7000.00},
-                'person': {
+        }
-                    '_id': p.pk,
-                    'salary': 7000.00
-                }
-            })
 
     def test_cached_reference_field_reference(self):
         class Group(Document):
@@ -111,17 +105,14 @@ class TestCachedReferenceField(MongoDBTestCase):
 
         class SocialData(Document):
             obs = StringField()
-            tags = ListField(
+            tags = ListField(StringField())
-                StringField())
+            person = CachedReferenceField(Person, fields=("group",))
-            person = CachedReferenceField(
-                Person,
-                fields=('group',))
 
         Group.drop_collection()
         Person.drop_collection()
         SocialData.drop_collection()
 
-        g1 = Group(name='dev')
+        g1 = Group(name="dev")
         g1.save()
 
         g2 = Group(name="designers")
@@ -136,25 +127,21 @@ class TestCachedReferenceField(MongoDBTestCase):
         p3 = Person(name="Afro design", group=g2)
         p3.save()
 
-        s1 = SocialData(obs="testing 123", person=p1, tags=['tag1', 'tag2'])
+        s1 = SocialData(obs="testing 123", person=p1, tags=["tag1", "tag2"])
         s1.save()
 
-        s2 = SocialData(obs="testing 321", person=p3, tags=['tag3', 'tag4'])
+        s2 = SocialData(obs="testing 321", person=p3, tags=["tag3", "tag4"])
         s2.save()
 
-        self.assertEqual(SocialData.objects._collection.find_one(
+        assert SocialData.objects._collection.find_one({"tags": "tag2"}) == {
-            {'tags': 'tag2'}), {
+            "_id": s1.pk,
-                '_id': s1.pk,
+            "obs": "testing 123",
-                'obs': 'testing 123',
+            "tags": ["tag1", "tag2"],
-                'tags': ['tag1', 'tag2'],
+            "person": {"_id": p1.pk, "group": g1.pk},
-                'person': {
+        }
-                    '_id': p1.pk,
-                    'group': g1.pk
-                }
-        })
 
-        self.assertEqual(SocialData.objects(person__group=g2).count(), 1)
+        assert SocialData.objects(person__group=g2).count() == 1
-        self.assertEqual(SocialData.objects(person__group=g2).first(), s2)
+        assert SocialData.objects(person__group=g2).first() == s2
 
     def test_cached_reference_field_push_with_fields(self):
         class Product(Document):
@@ -163,185 +150,136 @@ class TestCachedReferenceField(MongoDBTestCase):
         Product.drop_collection()
 
         class Basket(Document):
-            products = ListField(CachedReferenceField(Product, fields=['name']))
+            products = ListField(CachedReferenceField(Product, fields=["name"]))
 
         Basket.drop_collection()
-        product1 = Product(name='abc').save()
+        product1 = Product(name="abc").save()
-        product2 = Product(name='def').save()
+        product2 = Product(name="def").save()
         basket = Basket(products=[product1]).save()
-        self.assertEqual(
+        assert Basket.objects._collection.find_one() == {
-            Basket.objects._collection.find_one(),
+            "_id": basket.pk,
-            {
+            "products": [{"_id": product1.pk, "name": product1.name}],
-                '_id': basket.pk,
+        }
-                'products': [
-                    {
-                        '_id': product1.pk,
-                        'name': product1.name
-                    }
-                ]
-            }
-        )
         # push to list
         basket.update(push__products=product2)
         basket.reload()
-        self.assertEqual(
+        assert Basket.objects._collection.find_one() == {
-            Basket.objects._collection.find_one(),
+            "_id": basket.pk,
-            {
+            "products": [
-                '_id': basket.pk,
+                {"_id": product1.pk, "name": product1.name},
-                'products': [
+                {"_id": product2.pk, "name": product2.name},
-                    {
+            ],
-                        '_id': product1.pk,
+        }
-                        'name': product1.name
-                    },
-                    {
-                        '_id': product2.pk,
-                        'name': product2.name
-                    }
-                ]
-            }
-        )
 
     def test_cached_reference_field_update_all(self):
         class Person(Document):
-            TYPES = (
+            TYPES = (("pf", "PF"), ("pj", "PJ"))
-                ('pf', "PF"),
-                ('pj', "PJ")
-            )
             name = StringField()
             tp = StringField(choices=TYPES)
-            father = CachedReferenceField('self', fields=('tp',))
+            father = CachedReferenceField("self", fields=("tp",))
 
         Person.drop_collection()
 
         a1 = Person(name="Wilson Father", tp="pj")
         a1.save()
 
-        a2 = Person(name='Wilson Junior', tp='pf', father=a1)
+        a2 = Person(name="Wilson Junior", tp="pf", father=a1)
         a2.save()
 
         a2 = Person.objects.with_id(a2.id)
-        self.assertEqual(a2.father.tp, a1.tp)
+        assert a2.father.tp == a1.tp
 
-        self.assertEqual(dict(a2.to_mongo()), {
+        assert dict(a2.to_mongo()) == {
             "_id": a2.pk,
             "name": u"Wilson Junior",
             "tp": u"pf",
-            "father": {
+            "father": {"_id": a1.pk, "tp": u"pj"},
-                "_id": a1.pk,
+        }
-                "tp": u"pj"
-            }
-        })
 
-        self.assertEqual(Person.objects(father=a1)._query, {
+        assert Person.objects(father=a1)._query == {"father._id": a1.pk}
-            'father._id': a1.pk
+        assert Person.objects(father=a1).count() == 1
-        })
-        self.assertEqual(Person.objects(father=a1).count(), 1)
 
         Person.objects.update(set__tp="pf")
         Person.father.sync_all()
 
         a2.reload()
-        self.assertEqual(dict(a2.to_mongo()), {
+        assert dict(a2.to_mongo()) == {
             "_id": a2.pk,
             "name": u"Wilson Junior",
             "tp": u"pf",
-            "father": {
+            "father": {"_id": a1.pk, "tp": u"pf"},
-                "_id": a1.pk,
+        }
-                "tp": u"pf"
-            }
-        })
 
     def test_cached_reference_fields_on_embedded_documents(self):
-        with self.assertRaises(InvalidDocumentError):
+        with pytest.raises(InvalidDocumentError):
+
             class Test(Document):
                 name = StringField()
 
-            type('WrongEmbeddedDocument', (
+            type(
-                EmbeddedDocument,), {
+                "WrongEmbeddedDocument",
-                    'test': CachedReferenceField(Test)
+                (EmbeddedDocument,),
-            })
+                {"test": CachedReferenceField(Test)},
+            )
 
     def test_cached_reference_auto_sync(self):
         class Person(Document):
-            TYPES = (
+            TYPES = (("pf", "PF"), ("pj", "PJ"))
-                ('pf', "PF"),
-                ('pj', "PJ")
-            )
             name = StringField()
-            tp = StringField(
+            tp = StringField(choices=TYPES)
-                choices=TYPES
-            )
 
-            father = CachedReferenceField('self', fields=('tp',))
+            father = CachedReferenceField("self", fields=("tp",))
 
         Person.drop_collection()
 
         a1 = Person(name="Wilson Father", tp="pj")
         a1.save()
 
-        a2 = Person(name='Wilson Junior', tp='pf', father=a1)
+        a2 = Person(name="Wilson Junior", tp="pf", father=a1)
         a2.save()
 
-        a1.tp = 'pf'
+        a1.tp = "pf"
         a1.save()
 
         a2.reload()
-        self.assertEqual(dict(a2.to_mongo()), {
+        assert dict(a2.to_mongo()) == {
-            '_id': a2.pk,
+            "_id": a2.pk,
-            'name': 'Wilson Junior',
+            "name": "Wilson Junior",
-            'tp': 'pf',
+            "tp": "pf",
-            'father': {
+            "father": {"_id": a1.pk, "tp": "pf"},
-                '_id': a1.pk,
+        }
-                'tp': 'pf'
-            }
-        })
 
     def test_cached_reference_auto_sync_disabled(self):
         class Persone(Document):
-            TYPES = (
+            TYPES = (("pf", "PF"), ("pj", "PJ"))
-                ('pf', "PF"),
-                ('pj', "PJ")
-            )
             name = StringField()
-            tp = StringField(
+            tp = StringField(choices=TYPES)
-                choices=TYPES
-            )
 
-            father = CachedReferenceField(
+            father = CachedReferenceField("self", fields=("tp",), auto_sync=False)
-                'self', fields=('tp',), auto_sync=False)
 
         Persone.drop_collection()
 
         a1 = Persone(name="Wilson Father", tp="pj")
         a1.save()
 
-        a2 = Persone(name='Wilson Junior', tp='pf', father=a1)
+        a2 = Persone(name="Wilson Junior", tp="pf", father=a1)
         a2.save()
 
-        a1.tp = 'pf'
+        a1.tp = "pf"
         a1.save()
 
-        self.assertEqual(Persone.objects._collection.find_one({'_id': a2.pk}), {
+        assert Persone.objects._collection.find_one({"_id": a2.pk}) == {
-            '_id': a2.pk,
+            "_id": a2.pk,
-            'name': 'Wilson Junior',
+            "name": "Wilson Junior",
-            'tp': 'pf',
+            "tp": "pf",
-            'father': {
+            "father": {"_id": a1.pk, "tp": "pj"},
-                '_id': a1.pk,
+        }
-                'tp': 'pj'
-            }
-        })
 
     def test_cached_reference_embedded_fields(self):
         class Owner(EmbeddedDocument):
-            TPS = (
+            TPS = (("n", "Normal"), ("u", "Urgent"))
-                ('n', "Normal"),
-                ('u', "Urgent")
-            )
             name = StringField()
-            tp = StringField(
+            tp = StringField(verbose_name="Type", db_field="t", choices=TPS)
-                verbose_name="Type",
-                db_field="t",
-                choices=TPS)
 
         class Animal(Document):
             name = StringField()
@@ -351,45 +289,41 @@ class TestCachedReferenceField(MongoDBTestCase):
 
         class Ocorrence(Document):
             person = StringField()
-            animal = CachedReferenceField(
+            animal = CachedReferenceField(Animal, fields=["tag", "owner.tp"])
-                Animal, fields=['tag', 'owner.tp'])
 
         Animal.drop_collection()
         Ocorrence.drop_collection()
 
-        a = Animal(name="Leopard", tag="heavy",
+        a = Animal(
-                   owner=Owner(tp='u', name="Wilson Júnior")
+            name="Leopard", tag="heavy", owner=Owner(tp="u", name="Wilson Júnior")
-                   )
+        )
         a.save()
 
         o = Ocorrence(person="teste", animal=a)
         o.save()
-        self.assertEqual(dict(a.to_mongo(fields=['tag', 'owner.tp'])), {
+        assert dict(a.to_mongo(fields=["tag", "owner.tp"])) == {
-            '_id': a.pk,
+            "_id": a.pk,
-            'tag': 'heavy',
+            "tag": "heavy",
-            'owner': {
+            "owner": {"t": "u"},
-                't': 'u'
+        }
-            }
+        assert o.to_mongo()["animal"]["tag"] == "heavy"
-        })
+        assert o.to_mongo()["animal"]["owner"]["t"] == "u"
-        self.assertEqual(o.to_mongo()['animal']['tag'], 'heavy')
-        self.assertEqual(o.to_mongo()['animal']['owner']['t'], 'u')
 
         # Check to_mongo with fields
-        self.assertNotIn('animal', o.to_mongo(fields=['person']))
+        assert "animal" not in o.to_mongo(fields=["person"])
 
         # counts
         Ocorrence(person="teste 2").save()
         Ocorrence(person="teste 3").save()
 
-        count = Ocorrence.objects(
+        count = Ocorrence.objects(animal__tag="heavy", animal__owner__tp="u").count()
-            animal__tag='heavy', animal__owner__tp='u').count()
+        assert count == 1
-        self.assertEqual(count, 1)
 
         ocorrence = Ocorrence.objects(
-            animal__tag='heavy',
+            animal__tag="heavy", animal__owner__tp="u"
-            animal__owner__tp='u').first()
+        ).first()
-        self.assertEqual(ocorrence.person, "teste")
+        assert ocorrence.person == "teste"
-        self.assertIsInstance(ocorrence.animal, Animal)
+        assert isinstance(ocorrence.animal, Animal)
 
     def test_cached_reference_embedded_list_fields(self):
         class Owner(EmbeddedDocument):
@@ -404,43 +338,40 @@ class TestCachedReferenceField(MongoDBTestCase):
 
         class Ocorrence(Document):
             person = StringField()
-            animal = CachedReferenceField(
+            animal = CachedReferenceField(Animal, fields=["tag", "owner.tags"])
-                Animal, fields=['tag', 'owner.tags'])
 
         Animal.drop_collection()
         Ocorrence.drop_collection()
 
-        a = Animal(name="Leopard", tag="heavy",
+        a = Animal(
-                   owner=Owner(tags=['cool', 'funny'],
+            name="Leopard",
-                               name="Wilson Júnior")
+            tag="heavy",
-                   )
+            owner=Owner(tags=["cool", "funny"], name="Wilson Júnior"),
+        )
         a.save()
 
         o = Ocorrence(person="teste 2", animal=a)
         o.save()
-        self.assertEqual(dict(a.to_mongo(fields=['tag', 'owner.tags'])), {
+        assert dict(a.to_mongo(fields=["tag", "owner.tags"])) == {
-            '_id': a.pk,
+            "_id": a.pk,
-            'tag': 'heavy',
+            "tag": "heavy",
-            'owner': {
+            "owner": {"tags": ["cool", "funny"]},
-                'tags': ['cool', 'funny']
+        }
-            }
-        })
 
-        self.assertEqual(o.to_mongo()['animal']['tag'], 'heavy')
+        assert o.to_mongo()["animal"]["tag"] == "heavy"
-        self.assertEqual(o.to_mongo()['animal']['owner']['tags'],
+        assert o.to_mongo()["animal"]["owner"]["tags"] == ["cool", "funny"]
-                         ['cool', 'funny'])
 
         # counts
         Ocorrence(person="teste 2").save()
         Ocorrence(person="teste 3").save()
 
         query = Ocorrence.objects(
-            animal__tag='heavy', animal__owner__tags='cool')._query
+            animal__tag="heavy", animal__owner__tags="cool"
-        self.assertEqual(
+        )._query
-            query, {'animal.owner.tags': 'cool', 'animal.tag': 'heavy'})
+        assert query == {"animal.owner.tags": "cool", "animal.tag": "heavy"}
 
         ocorrence = Ocorrence.objects(
-            animal__tag='heavy',
+            animal__tag="heavy", animal__owner__tags="cool"
-            animal__owner__tags='cool').first()
+        ).first()
-        self.assertEqual(ocorrence.person, "teste 2")
+        assert ocorrence.person == "teste 2"
-        self.assertIsInstance(ocorrence.animal, Animal)
+        assert isinstance(ocorrence.animal, Animal)

tests/fields/test_complex_datetime_field.py

@@ -1,9 +1,11 @@
 # -*- coding: utf-8 -*-
 import datetime
-import math
 import itertools
+import math
 import re
 
+import pytest
+
 from mongoengine import *
 
 from tests.utils import MongoDBTestCase
@@ -14,9 +16,10 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         """Tests for complex datetime fields - which can handle
         microseconds without rounding.
         """
+
         class LogEntry(Document):
             date = ComplexDateTimeField()
-            date_with_dots = ComplexDateTimeField(separator='.')
+            date_with_dots = ComplexDateTimeField(separator=".")
 
         LogEntry.drop_collection()
 
@@ -27,7 +30,7 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         log.date = d1
         log.save()
         log.reload()
-        self.assertEqual(log.date, d1)
+        assert log.date == d1
 
         # Post UTC - microseconds are rounded (down) nearest millisecond - with
         # default datetimefields
@@ -35,7 +38,7 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         log.date = d1
         log.save()
         log.reload()
-        self.assertEqual(log.date, d1)
+        assert log.date == d1
 
         # Pre UTC dates microseconds below 1000 are dropped - with default
         # datetimefields
@@ -43,7 +46,7 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         log.date = d1
         log.save()
         log.reload()
-        self.assertEqual(log.date, d1)
+        assert log.date == d1
 
         # Pre UTC microseconds above 1000 is wonky - with default datetimefields
         # log.date has an invalid microsecond value so I can't construct
@@ -53,26 +56,34 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
             log.date = d1
             log.save()
             log.reload()
-            self.assertEqual(log.date, d1)
+            assert log.date == d1
             log1 = LogEntry.objects.get(date=d1)
-            self.assertEqual(log, log1)
+            assert log == log1
 
         # Test string padding
         microsecond = map(int, [math.pow(10, x) for x in range(6)])
         mm = dd = hh = ii = ss = [1, 10]
 
         for values in itertools.product([2014], mm, dd, hh, ii, ss, microsecond):
-            stored = LogEntry(date=datetime.datetime(*values)).to_mongo()['date']
+            stored = LogEntry(date=datetime.datetime(*values)).to_mongo()["date"]
-            self.assertTrue(re.match('^\d{4},\d{2},\d{2},\d{2},\d{2},\d{2},\d{6}$', stored) is not None)
+            assert (
+                re.match(r"^\d{4},\d{2},\d{2},\d{2},\d{2},\d{2},\d{6}$", stored)
+                is not None
+            )
 
         # Test separator
-        stored = LogEntry(date_with_dots=datetime.datetime(2014, 1, 1)).to_mongo()['date_with_dots']
+        stored = LogEntry(date_with_dots=datetime.datetime(2014, 1, 1)).to_mongo()[
-        self.assertTrue(re.match('^\d{4}.\d{2}.\d{2}.\d{2}.\d{2}.\d{2}.\d{6}$', stored) is not None)
+            "date_with_dots"
+        ]
+        assert (
+            re.match(r"^\d{4}.\d{2}.\d{2}.\d{2}.\d{2}.\d{2}.\d{6}$", stored) is not None
+        )
 
     def test_complexdatetime_usage(self):
         """Tests for complex datetime fields - which can handle
         microseconds without rounding.
         """
+
         class LogEntry(Document):
             date = ComplexDateTimeField()
 
@@ -84,62 +95,61 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         log.save()
 
         log1 = LogEntry.objects.get(date=d1)
-        self.assertEqual(log, log1)
+        assert log == log1
 
         # create extra 59 log entries for a total of 60
         for i in range(1951, 2010):
             d = datetime.datetime(i, 1, 1, 0, 0, 1, 999)
             LogEntry(date=d).save()
 
-        self.assertEqual(LogEntry.objects.count(), 60)
+        assert LogEntry.objects.count() == 60
 
         # Test ordering
         logs = LogEntry.objects.order_by("date")
         i = 0
         while i < 59:
-            self.assertTrue(logs[i].date <= logs[i + 1].date)
+            assert logs[i].date <= logs[i + 1].date
             i += 1
 
         logs = LogEntry.objects.order_by("-date")
         i = 0
         while i < 59:
-            self.assertTrue(logs[i].date >= logs[i + 1].date)
+            assert logs[i].date >= logs[i + 1].date
             i += 1
 
         # Test searching
         logs = LogEntry.objects.filter(date__gte=datetime.datetime(1980, 1, 1))
-        self.assertEqual(logs.count(), 30)
+        assert logs.count() == 30
 
         logs = LogEntry.objects.filter(date__lte=datetime.datetime(1980, 1, 1))
-        self.assertEqual(logs.count(), 30)
+        assert logs.count() == 30
 
         logs = LogEntry.objects.filter(
             date__lte=datetime.datetime(2011, 1, 1),
             date__gte=datetime.datetime(2000, 1, 1),
         )
-        self.assertEqual(logs.count(), 10)
+        assert logs.count() == 10
 
         LogEntry.drop_collection()
 
         # Test microsecond-level ordering/filtering
         for microsecond in (99, 999, 9999, 10000):
-            LogEntry(
+            LogEntry(date=datetime.datetime(2015, 1, 1, 0, 0, 0, microsecond)).save()
-                date=datetime.datetime(2015, 1, 1, 0, 0, 0, microsecond)
-            ).save()
 
-        logs = list(LogEntry.objects.order_by('date'))
+        logs = list(LogEntry.objects.order_by("date"))
         for next_idx, log in enumerate(logs[:-1], start=1):
             next_log = logs[next_idx]
-            self.assertTrue(log.date < next_log.date)
+            assert log.date < next_log.date
 
-        logs = list(LogEntry.objects.order_by('-date'))
+        logs = list(LogEntry.objects.order_by("-date"))
         for next_idx, log in enumerate(logs[:-1], start=1):
             next_log = logs[next_idx]
-            self.assertTrue(log.date > next_log.date)
+            assert log.date > next_log.date
 
         logs = LogEntry.objects.filter(
-            date__lte=datetime.datetime(2015, 1, 1, 0, 0, 0, 10000))
+            date__lte=datetime.datetime(2015, 1, 1, 0, 0, 0, 10000)
-        self.assertEqual(logs.count(), 4)
+        )
+        assert logs.count() == 4
 
     def test_no_default_value(self):
         class Log(Document):
@@ -148,25 +158,26 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         Log.drop_collection()
 
         log = Log()
-        self.assertIsNone(log.timestamp)
+        assert log.timestamp is None
         log.save()
 
         fetched_log = Log.objects.with_id(log.id)
-        self.assertIsNone(fetched_log.timestamp)
+        assert fetched_log.timestamp is None
 
     def test_default_static_value(self):
         NOW = datetime.datetime.utcnow()
+
         class Log(Document):
             timestamp = ComplexDateTimeField(default=NOW)
 
         Log.drop_collection()
 
         log = Log()
-        self.assertEqual(log.timestamp, NOW)
+        assert log.timestamp == NOW
         log.save()
 
         fetched_log = Log.objects.with_id(log.id)
-        self.assertEqual(fetched_log.timestamp, NOW)
+        assert fetched_log.timestamp == NOW
 
     def test_default_callable(self):
         NOW = datetime.datetime.utcnow()
@@ -177,8 +188,23 @@ class ComplexDateTimeFieldTest(MongoDBTestCase):
         Log.drop_collection()
 
         log = Log()
-        self.assertGreaterEqual(log.timestamp, NOW)
+        assert log.timestamp >= NOW
         log.save()
 
         fetched_log = Log.objects.with_id(log.id)
-        self.assertGreaterEqual(fetched_log.timestamp, NOW)
+        assert fetched_log.timestamp >= NOW
+
+    def test_setting_bad_value_does_not_raise_unless_validate_is_called(self):
+        # test regression of #2253
+
+        class Log(Document):
+            timestamp = ComplexDateTimeField()
+
+        Log.drop_collection()
+
+        log = Log(timestamp="garbage")
+        with pytest.raises(ValidationError):
+            log.validate()
+
+        with pytest.raises(ValidationError):
+            log.save()

tests/fields/test_date_field.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 import datetime
-import six
+
+import pytest
 
 try:
     import dateutil
@@ -8,7 +9,6 @@ except ImportError:
     dateutil = None
 
 from mongoengine import *
-
 from tests.utils import MongoDBTestCase
 
 
@@ -18,41 +18,47 @@ class TestDateField(MongoDBTestCase):
         Ensure an exception is raised when trying to
         cast an empty string to datetime.
         """
+
         class MyDoc(Document):
             dt = DateField()
 
-        md = MyDoc(dt='')
+        md = MyDoc(dt="")
-        self.assertRaises(ValidationError, md.save)
+        with pytest.raises(ValidationError):
+            md.save()
 
     def test_date_from_whitespace_string(self):
         """
         Ensure an exception is raised when trying to
         cast a whitespace-only string to datetime.
         """
+
         class MyDoc(Document):
             dt = DateField()
 
-        md = MyDoc(dt='   ')
+        md = MyDoc(dt="   ")
-        self.assertRaises(ValidationError, md.save)
+        with pytest.raises(ValidationError):
+            md.save()
 
     def test_default_values_today(self):
         """Ensure that default field values are used when creating
         a document.
         """
+
         class Person(Document):
             day = DateField(default=datetime.date.today)
 
         person = Person()
         person.validate()
-        self.assertEqual(person.day, person.day)
+        assert person.day == person.day
-        self.assertEqual(person.day, datetime.date.today())
+        assert person.day == datetime.date.today()
-        self.assertEqual(person._data['day'], person.day)
+        assert person._data["day"] == person.day
 
     def test_date(self):
         """Tests showing pymongo date fields
 
         See: http://api.mongodb.org/python/current/api/bson/son.html#dt
         """
+
         class LogEntry(Document):
             date = DateField()
 
@@ -63,7 +69,7 @@ class TestDateField(MongoDBTestCase):
         log.date = datetime.date.today()
         log.save()
         log.reload()
-        self.assertEqual(log.date, datetime.date.today())
+        assert log.date == datetime.date.today()
 
         d1 = datetime.datetime(1970, 1, 1, 0, 0, 1, 999)
         d2 = datetime.datetime(1970, 1, 1, 0, 0, 1)
@@ -71,30 +77,20 @@ class TestDateField(MongoDBTestCase):
         log.date = d1
         log.save()
         log.reload()
-        self.assertEqual(log.date, d1.date())
+        assert log.date == d1.date()
-        self.assertEqual(log.date, d2.date())
+        assert log.date == d2.date()
 
         d1 = datetime.datetime(1970, 1, 1, 0, 0, 1, 9999)
         d2 = datetime.datetime(1970, 1, 1, 0, 0, 1, 9000)
         log.date = d1
         log.save()
         log.reload()
-        self.assertEqual(log.date, d1.date())
+        assert log.date == d1.date()
-        self.assertEqual(log.date, d2.date())
+        assert log.date == d2.date()
-
-        if not six.PY3:
-            # Pre UTC dates microseconds below 1000 are dropped
-            # This does not seem to be true in PY3
-            d1 = datetime.datetime(1969, 12, 31, 23, 59, 59, 999)
-            d2 = datetime.datetime(1969, 12, 31, 23, 59, 59)
-            log.date = d1
-            log.save()
-            log.reload()
-            self.assertEqual(log.date, d1.date())
-            self.assertEqual(log.date, d2.date())
 
     def test_regular_usage(self):
         """Tests for regular datetime fields"""
+
         class LogEntry(Document):
             date = DateField()
 
@@ -106,42 +102,43 @@ class TestDateField(MongoDBTestCase):
         log.validate()
         log.save()
 
-        for query in (d1, d1.isoformat(' ')):
+        for query in (d1, d1.isoformat(" ")):
             log1 = LogEntry.objects.get(date=query)
-            self.assertEqual(log, log1)
+            assert log == log1
 
         if dateutil:
-            log1 = LogEntry.objects.get(date=d1.isoformat('T'))
+            log1 = LogEntry.objects.get(date=d1.isoformat("T"))
-            self.assertEqual(log, log1)
+            assert log == log1
 
         # create additional 19 log entries for a total of 20
         for i in range(1971, 1990):
             d = datetime.datetime(i, 1, 1, 0, 0, 1)
             LogEntry(date=d).save()
 
-        self.assertEqual(LogEntry.objects.count(), 20)
+        assert LogEntry.objects.count() == 20
 
         # Test ordering
         logs = LogEntry.objects.order_by("date")
         i = 0
         while i < 19:
-            self.assertTrue(logs[i].date <= logs[i + 1].date)
+            assert logs[i].date <= logs[i + 1].date
             i += 1
 
         logs = LogEntry.objects.order_by("-date")
         i = 0
         while i < 19:
-            self.assertTrue(logs[i].date >= logs[i + 1].date)
+            assert logs[i].date >= logs[i + 1].date
             i += 1
 
         # Test searching
         logs = LogEntry.objects.filter(date__gte=datetime.datetime(1980, 1, 1))
-        self.assertEqual(logs.count(), 10)
+        assert logs.count() == 10
 
     def test_validation(self):
         """Ensure that invalid values cannot be assigned to datetime
         fields.
         """
+
         class LogEntry(Document):
             time = DateField()
 
@@ -152,14 +149,16 @@ class TestDateField(MongoDBTestCase):
         log.time = datetime.date.today()
         log.validate()
 
-        log.time = datetime.datetime.now().isoformat(' ')
+        log.time = datetime.datetime.now().isoformat(" ")
         log.validate()
 
         if dateutil:
-            log.time = datetime.datetime.now().isoformat('T')
+            log.time = datetime.datetime.now().isoformat("T")
             log.validate()
 
         log.time = -1
-        self.assertRaises(ValidationError, log.validate)
+        with pytest.raises(ValidationError):
-        log.time = 'ABC'
+            log.validate()
-        self.assertRaises(ValidationError, log.validate)
+        log.time = "ABC"
+        with pytest.raises(ValidationError):
+            log.validate()

tests/fields/test_datetime_field.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 import datetime as dt
-import six
+
+import pytest
 
 try:
     import dateutil
@@ -19,27 +20,32 @@ class TestDateTimeField(MongoDBTestCase):
         Ensure an exception is raised when trying to
         cast an empty string to datetime.
         """
+
         class MyDoc(Document):
             dt = DateTimeField()
 
-        md = MyDoc(dt='')
+        md = MyDoc(dt="")
-        self.assertRaises(ValidationError, md.save)
+        with pytest.raises(ValidationError):
+            md.save()
 
     def test_datetime_from_whitespace_string(self):
         """
         Ensure an exception is raised when trying to
         cast a whitespace-only string to datetime.
         """
+
         class MyDoc(Document):
             dt = DateTimeField()
 
-        md = MyDoc(dt='   ')
+        md = MyDoc(dt="   ")
-        self.assertRaises(ValidationError, md.save)
+        with pytest.raises(ValidationError):
+            md.save()
 
     def test_default_value_utcnow(self):
         """Ensure that default field values are used when creating
         a document.
         """
+
         class Person(Document):
             created = DateTimeField(default=dt.datetime.utcnow)
 
@@ -47,9 +53,9 @@ class TestDateTimeField(MongoDBTestCase):
         person = Person()
         person.validate()
         person_created_t0 = person.created
-        self.assertLess(person.created - utcnow, dt.timedelta(seconds=1))
+        assert person.created - utcnow < dt.timedelta(seconds=1)
-        self.assertEqual(person_created_t0, person.created)  # make sure it does not change
+        assert person_created_t0 == person.created  # make sure it does not change
-        self.assertEqual(person._data['created'], person.created)
+        assert person._data["created"] == person.created
 
     def test_handling_microseconds(self):
         """Tests showing pymongo datetime fields handling of microseconds.
@@ -58,6 +64,7 @@ class TestDateTimeField(MongoDBTestCase):
 
         See: http://api.mongodb.org/python/current/api/bson/son.html#dt
         """
+
         class LogEntry(Document):
             date = DateTimeField()
 
@@ -68,7 +75,7 @@ class TestDateTimeField(MongoDBTestCase):
         log.date = dt.date.today()
         log.save()
         log.reload()
-        self.assertEqual(log.date.date(), dt.date.today())
+        assert log.date.date() == dt.date.today()
 
         # Post UTC - microseconds are rounded (down) nearest millisecond and
         # dropped
@@ -78,8 +85,8 @@ class TestDateTimeField(MongoDBTestCase):
         log.date = d1
         log.save()
         log.reload()
-        self.assertNotEqual(log.date, d1)
+        assert log.date != d1
-        self.assertEqual(log.date, d2)
+        assert log.date == d2
 
         # Post UTC - microseconds are rounded (down) nearest millisecond
         d1 = dt.datetime(1970, 1, 1, 0, 0, 1, 9999)
@@ -87,22 +94,12 @@ class TestDateTimeField(MongoDBTestCase):
         log.date = d1
         log.save()
         log.reload()
-        self.assertNotEqual(log.date, d1)
+        assert log.date != d1
-        self.assertEqual(log.date, d2)
+        assert log.date == d2
-
-        if not six.PY3:
-            # Pre UTC dates microseconds below 1000 are dropped
-            # This does not seem to be true in PY3
-            d1 = dt.datetime(1969, 12, 31, 23, 59, 59, 999)
-            d2 = dt.datetime(1969, 12, 31, 23, 59, 59)
-            log.date = d1
-            log.save()
-            log.reload()
-            self.assertNotEqual(log.date, d1)
-            self.assertEqual(log.date, d2)
 
     def test_regular_usage(self):
         """Tests for regular datetime fields"""
+
         class LogEntry(Document):
             date = DateTimeField()
 
@@ -114,51 +111,51 @@ class TestDateTimeField(MongoDBTestCase):
         log.validate()
         log.save()
 
-        for query in (d1, d1.isoformat(' ')):
+        for query in (d1, d1.isoformat(" ")):
             log1 = LogEntry.objects.get(date=query)
-            self.assertEqual(log, log1)
+            assert log == log1
 
         if dateutil:
-            log1 = LogEntry.objects.get(date=d1.isoformat('T'))
+            log1 = LogEntry.objects.get(date=d1.isoformat("T"))
-            self.assertEqual(log, log1)
+            assert log == log1
 
         # create additional 19 log entries for a total of 20
         for i in range(1971, 1990):
             d = dt.datetime(i, 1, 1, 0, 0, 1)
             LogEntry(date=d).save()
 
-        self.assertEqual(LogEntry.objects.count(), 20)
+        assert LogEntry.objects.count() == 20
 
         # Test ordering
         logs = LogEntry.objects.order_by("date")
         i = 0
         while i < 19:
-            self.assertTrue(logs[i].date <= logs[i + 1].date)
+            assert logs[i].date <= logs[i + 1].date
             i += 1
 
         logs = LogEntry.objects.order_by("-date")
         i = 0
         while i < 19:
-            self.assertTrue(logs[i].date >= logs[i + 1].date)
+            assert logs[i].date >= logs[i + 1].date
             i += 1
 
         # Test searching
         logs = LogEntry.objects.filter(date__gte=dt.datetime(1980, 1, 1))
-        self.assertEqual(logs.count(), 10)
+        assert logs.count() == 10
 
         logs = LogEntry.objects.filter(date__lte=dt.datetime(1980, 1, 1))
-        self.assertEqual(logs.count(), 10)
+        assert logs.count() == 10
 
         logs = LogEntry.objects.filter(
-            date__lte=dt.datetime(1980, 1, 1),
+            date__lte=dt.datetime(1980, 1, 1), date__gte=dt.datetime(1975, 1, 1)
-            date__gte=dt.datetime(1975, 1, 1),
         )
-        self.assertEqual(logs.count(), 5)
+        assert logs.count() == 5
 
     def test_datetime_validation(self):
         """Ensure that invalid values cannot be assigned to datetime
         fields.
         """
+
         class LogEntry(Document):
             time = DateTimeField()
 
@@ -169,45 +166,51 @@ class TestDateTimeField(MongoDBTestCase):
         log.time = dt.date.today()
         log.validate()
 
-        log.time = dt.datetime.now().isoformat(' ')
+        log.time = dt.datetime.now().isoformat(" ")
         log.validate()
 
-        log.time = '2019-05-16 21:42:57.897847'
+        log.time = "2019-05-16 21:42:57.897847"
         log.validate()
 
         if dateutil:
-            log.time = dt.datetime.now().isoformat('T')
+            log.time = dt.datetime.now().isoformat("T")
             log.validate()
 
         log.time = -1
-        self.assertRaises(ValidationError, log.validate)
+        with pytest.raises(ValidationError):
-        log.time = 'ABC'
+            log.validate()
-        self.assertRaises(ValidationError, log.validate)
+        log.time = "ABC"
-        log.time = '2019-05-16 21:GARBAGE:12'
+        with pytest.raises(ValidationError):
-        self.assertRaises(ValidationError, log.validate)
+            log.validate()
-        log.time = '2019-05-16 21:42:57.GARBAGE'
+        log.time = "2019-05-16 21:GARBAGE:12"
-        self.assertRaises(ValidationError, log.validate)
+        with pytest.raises(ValidationError):
-        log.time = '2019-05-16 21:42:57.123.456'
+            log.validate()
-        self.assertRaises(ValidationError, log.validate)
+        log.time = "2019-05-16 21:42:57.GARBAGE"
+        with pytest.raises(ValidationError):
+            log.validate()
+        log.time = "2019-05-16 21:42:57.123.456"
+        with pytest.raises(ValidationError):
+            log.validate()
 
     def test_parse_datetime_as_str(self):
         class DTDoc(Document):
             date = DateTimeField()
 
-        date_str = '2019-03-02 22:26:01'
+        date_str = "2019-03-02 22:26:01"
 
         # make sure that passing a parsable datetime works
         dtd = DTDoc()
         dtd.date = date_str
-        self.assertIsInstance(dtd.date, six.string_types)
+        assert isinstance(dtd.date, str)
         dtd.save()
         dtd.reload()
 
-        self.assertIsInstance(dtd.date, dt.datetime)
+        assert isinstance(dtd.date, dt.datetime)
-        self.assertEqual(str(dtd.date), date_str)
+        assert str(dtd.date) == date_str
 
-        dtd.date = 'January 1st, 9999999999'
+        dtd.date = "January 1st, 9999999999"
-        self.assertRaises(ValidationError, dtd.validate)
+        with pytest.raises(ValidationError):
+            dtd.validate()
 
 
 class TestDateTimeTzAware(MongoDBTestCase):
@@ -217,7 +220,7 @@ class TestDateTimeTzAware(MongoDBTestCase):
         connection._connections = {}
         connection._dbs = {}
 
-        connect(db='mongoenginetest', tz_aware=True)
+        connect(db="mongoenginetest", tz_aware=True)
 
         class LogEntry(Document):
             time = DateTimeField()
@@ -228,4 +231,4 @@ class TestDateTimeTzAware(MongoDBTestCase):
 
         log = LogEntry.objects.first()
         log.time = dt.datetime(2013, 1, 1, 0, 0, 0)
-        self.assertEqual(['time'], log._changed_fields)
+        assert ["time"] == log._changed_fields

tests/fields/test_decimal_field.py

@@ -1,39 +1,44 @@
 # -*- coding: utf-8 -*-
 from decimal import Decimal
 
-from mongoengine import *
+import pytest
 
+from mongoengine import *
 from tests.utils import MongoDBTestCase
 
 
 class TestDecimalField(MongoDBTestCase):
-
     def test_validation(self):
         """Ensure that invalid values cannot be assigned to decimal fields.
         """
+
         class Person(Document):
-            height = DecimalField(min_value=Decimal('0.1'),
+            height = DecimalField(min_value=Decimal("0.1"), max_value=Decimal("3.5"))
-                                  max_value=Decimal('3.5'))
 
         Person.drop_collection()
 
-        Person(height=Decimal('1.89')).save()
+        Person(height=Decimal("1.89")).save()
         person = Person.objects.first()
-        self.assertEqual(person.height, Decimal('1.89'))
+        assert person.height == Decimal("1.89")
 
-        person.height = '2.0'
+        person.height = "2.0"
         person.save()
         person.height = 0.01
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
-        person.height = Decimal('0.01')
+            person.validate()
-        self.assertRaises(ValidationError, person.validate)
+        person.height = Decimal("0.01")
-        person.height = Decimal('4.0')
+        with pytest.raises(ValidationError):
-        self.assertRaises(ValidationError, person.validate)
+            person.validate()
-        person.height = 'something invalid'
+        person.height = Decimal("4.0")
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
+        person.height = "something invalid"
+        with pytest.raises(ValidationError):
+            person.validate()
 
-        person_2 = Person(height='something invalid')
+        person_2 = Person(height="something invalid")
-        self.assertRaises(ValidationError, person_2.validate)
+        with pytest.raises(ValidationError):
+            person_2.validate()
 
     def test_comparison(self):
         class Person(Document):
@@ -46,11 +51,11 @@ class TestDecimalField(MongoDBTestCase):
         Person(money=8).save()
         Person(money=10).save()
 
-        self.assertEqual(2, Person.objects(money__gt=Decimal("7")).count())
+        assert 2 == Person.objects(money__gt=Decimal("7")).count()
-        self.assertEqual(2, Person.objects(money__gt=7).count())
+        assert 2 == Person.objects(money__gt=7).count()
-        self.assertEqual(2, Person.objects(money__gt="7").count())
+        assert 2 == Person.objects(money__gt="7").count()
 
-        self.assertEqual(3, Person.objects(money__gte="7").count())
+        assert 3 == Person.objects(money__gte="7").count()
 
     def test_storage(self):
         class Person(Document):
@@ -58,7 +63,14 @@ class TestDecimalField(MongoDBTestCase):
             string_value = DecimalField(precision=4, force_string=True)
 
         Person.drop_collection()
-        values_to_store = [10, 10.1, 10.11, "10.111", Decimal("10.1111"), Decimal("10.11111")]
+        values_to_store = [
+            10,
+            10.1,
+            10.11,
+            "10.111",
+            Decimal("10.1111"),
+            Decimal("10.11111"),
+        ]
         for store_at_creation in [True, False]:
             for value in values_to_store:
                 # to_python is called explicitly if values were sent in the kwargs of __init__
@@ -72,20 +84,27 @@ class TestDecimalField(MongoDBTestCase):
 
         # How its stored
         expected = [
-            {'float_value': 10.0, 'string_value': '10.0000'},
+            {"float_value": 10.0, "string_value": "10.0000"},
-            {'float_value': 10.1, 'string_value': '10.1000'},
+            {"float_value": 10.1, "string_value": "10.1000"},
-            {'float_value': 10.11, 'string_value': '10.1100'},
+            {"float_value": 10.11, "string_value": "10.1100"},
-            {'float_value': 10.111, 'string_value': '10.1110'},
+            {"float_value": 10.111, "string_value": "10.1110"},
-            {'float_value': 10.1111, 'string_value': '10.1111'},
+            {"float_value": 10.1111, "string_value": "10.1111"},
-            {'float_value': 10.1111, 'string_value': '10.1111'}]
+            {"float_value": 10.1111, "string_value": "10.1111"},
+        ]
         expected.extend(expected)
-        actual = list(Person.objects.exclude('id').as_pymongo())
+        actual = list(Person.objects.exclude("id").as_pymongo())
-        self.assertEqual(expected, actual)
+        assert expected == actual
 
         # How it comes out locally
-        expected = [Decimal('10.0000'), Decimal('10.1000'), Decimal('10.1100'),
+        expected = [
-                    Decimal('10.1110'), Decimal('10.1111'), Decimal('10.1111')]
+            Decimal("10.0000"),
+            Decimal("10.1000"),
+            Decimal("10.1100"),
+            Decimal("10.1110"),
+            Decimal("10.1111"),
+            Decimal("10.1111"),
+        ]
         expected.extend(expected)
-        for field_name in ['float_value', 'string_value']:
+        for field_name in ["float_value", "string_value"]:
             actual = list(Person.objects().scalar(field_name))
-            self.assertEqual(expected, actual)
+            assert expected == actual

tests/fields/test_dict_field.py

@@ -1,100 +1,123 @@
 # -*- coding: utf-8 -*-
+from bson import InvalidDocument
+import pytest
+
 from mongoengine import *
 from mongoengine.base import BaseDict
+from mongoengine.mongodb_support import MONGODB_36, get_mongodb_version
 
 from tests.utils import MongoDBTestCase, get_as_pymongo
 
 
 class TestDictField(MongoDBTestCase):
-
     def test_storage(self):
         class BlogPost(Document):
             info = DictField()
 
         BlogPost.drop_collection()
 
-        info = {'testkey': 'testvalue'}
+        info = {"testkey": "testvalue"}
         post = BlogPost(info=info).save()
-        self.assertEqual(
+        assert get_as_pymongo(post) == {"_id": post.id, "info": info}
-            get_as_pymongo(post),
-            {
-                '_id': post.id,
-                'info': info
-            }
-        )
 
-    def test_general_things(self):
+    def test_validate_invalid_type(self):
-        """Ensure that dict types work as expected."""
+        class BlogPost(Document):
+            info = DictField()
+
+        BlogPost.drop_collection()
+
+        invalid_infos = ["my post", ["test", "test"], {1: "test"}]
+        for invalid_info in invalid_infos:
+            with pytest.raises(ValidationError):
+                BlogPost(info=invalid_info).validate()
+
+    def test_keys_with_dots_or_dollars(self):
         class BlogPost(Document):
             info = DictField()
 
         BlogPost.drop_collection()
 
         post = BlogPost()
-        post.info = 'my post'
-        self.assertRaises(ValidationError, post.validate)
 
-        post.info = ['test', 'test']
+        post.info = {"$title": "test"}
-        self.assertRaises(ValidationError, post.validate)
+        with pytest.raises(ValidationError):
+            post.validate()
 
-        post.info = {'$title': 'test'}
+        post.info = {"nested": {"$title": "test"}}
-        self.assertRaises(ValidationError, post.validate)
+        with pytest.raises(ValidationError):
+            post.validate()
 
-        post.info = {'nested': {'$title': 'test'}}
+        post.info = {"$title.test": "test"}
-        self.assertRaises(ValidationError, post.validate)
+        with pytest.raises(ValidationError):
+            post.validate()
 
-        post.info = {'the.title': 'test'}
+        post.info = {"nested": {"the.title": "test"}}
-        self.assertRaises(ValidationError, post.validate)
+        if get_mongodb_version() < MONGODB_36:
+            # MongoDB < 3.6 rejects dots
+            # To avoid checking the mongodb version from the DictField class
+            # we rely on MongoDB to reject the data during the save
+            post.validate()
+            with pytest.raises(InvalidDocument):
+                post.save()
+        else:
+            post.validate()
 
-        post.info = {'nested': {'the.title': 'test'}}
+        post.info = {"dollar_and_dot": {"te$st.test": "test"}}
-        self.assertRaises(ValidationError, post.validate)
+        if get_mongodb_version() < MONGODB_36:
+            post.validate()
+            with pytest.raises(InvalidDocument):
+                post.save()
+        else:
+            post.validate()
 
-        post.info = {1: 'test'}
+    def test_general_things(self):
-        self.assertRaises(ValidationError, post.validate)
+        """Ensure that dict types work as expected."""
 
-        post.info = {'title': 'test'}
+        class BlogPost(Document):
+            info = DictField()
+
+        BlogPost.drop_collection()
+
+        post = BlogPost(info={"title": "test"})
         post.save()
 
         post = BlogPost()
-        post.info = {'title': 'dollar_sign', 'details': {'te$t': 'test'}}
+        post.info = {"title": "dollar_sign", "details": {"te$t": "test"}}
         post.save()
 
         post = BlogPost()
-        post.info = {'details': {'test': 'test'}}
+        post.info = {"details": {"test": "test"}}
         post.save()
 
         post = BlogPost()
-        post.info = {'details': {'test': 3}}
+        post.info = {"details": {"test": 3}}
         post.save()
 
-        self.assertEqual(BlogPost.objects.count(), 4)
+        assert BlogPost.objects.count() == 4
-        self.assertEqual(
+        assert BlogPost.objects.filter(info__title__exact="test").count() == 1
-            BlogPost.objects.filter(info__title__exact='test').count(), 1)
+        assert BlogPost.objects.filter(info__details__test__exact="test").count() == 1
-        self.assertEqual(
-            BlogPost.objects.filter(info__details__test__exact='test').count(), 1)
 
-        post = BlogPost.objects.filter(info__title__exact='dollar_sign').first()
+        post = BlogPost.objects.filter(info__title__exact="dollar_sign").first()
-        self.assertIn('te$t', post['info']['details'])
+        assert "te$t" in post["info"]["details"]
 
         # Confirm handles non strings or non existing keys
-        self.assertEqual(
+        assert BlogPost.objects.filter(info__details__test__exact=5).count() == 0
-            BlogPost.objects.filter(info__details__test__exact=5).count(), 0)
+        assert BlogPost.objects.filter(info__made_up__test__exact="test").count() == 0
-        self.assertEqual(
-            BlogPost.objects.filter(info__made_up__test__exact='test').count(), 0)
 
-        post = BlogPost.objects.create(info={'title': 'original'})
+        post = BlogPost.objects.create(info={"title": "original"})
-        post.info.update({'title': 'updated'})
+        post.info.update({"title": "updated"})
         post.save()
         post.reload()
-        self.assertEqual('updated', post.info['title'])
+        assert "updated" == post.info["title"]
 
-        post.info.setdefault('authors', [])
+        post.info.setdefault("authors", [])
         post.save()
         post.reload()
-        self.assertEqual([], post.info['authors'])
+        assert post.info["authors"] == []
 
     def test_dictfield_dump_document(self):
         """Ensure a DictField can handle another document's dump."""
+
         class Doc(Document):
             field = DictField()
 
@@ -106,51 +129,60 @@ class TestDictField(MongoDBTestCase):
             id = IntField(primary_key=True, default=1)
             recursive = DictField()
 
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
         class ToEmbedChild(ToEmbedParent):
             pass
 
         to_embed_recursive = ToEmbed(id=1).save()
         to_embed = ToEmbed(
-            id=2, recursive=to_embed_recursive.to_mongo().to_dict()).save()
+            id=2, recursive=to_embed_recursive.to_mongo().to_dict()
+        ).save()
         doc = Doc(field=to_embed.to_mongo().to_dict())
         doc.save()
-        self.assertIsInstance(doc.field, dict)
+        assert isinstance(doc.field, dict)
-        self.assertEqual(doc.field, {'_id': 2, 'recursive': {'_id': 1, 'recursive': {}}})
+        assert doc.field == {"_id": 2, "recursive": {"_id": 1, "recursive": {}}}
         # Same thing with a Document with a _cls field
         to_embed_recursive = ToEmbedChild(id=1).save()
         to_embed_child = ToEmbedChild(
-            id=2, recursive=to_embed_recursive.to_mongo().to_dict()).save()
+            id=2, recursive=to_embed_recursive.to_mongo().to_dict()
+        ).save()
         doc = Doc(field=to_embed_child.to_mongo().to_dict())
         doc.save()
-        self.assertIsInstance(doc.field, dict)
+        assert isinstance(doc.field, dict)
         expected = {
-            '_id': 2, '_cls': 'ToEmbedParent.ToEmbedChild',
+            "_id": 2,
-            'recursive': {'_id': 1, '_cls': 'ToEmbedParent.ToEmbedChild', 'recursive': {}}
+            "_cls": "ToEmbedParent.ToEmbedChild",
+            "recursive": {
+                "_id": 1,
+                "_cls": "ToEmbedParent.ToEmbedChild",
+                "recursive": {},
+            },
         }
-        self.assertEqual(doc.field, expected)
+        assert doc.field == expected
 
     def test_dictfield_strict(self):
         """Ensure that dict field handles validation if provided a strict field type."""
+
         class Simple(Document):
             mapping = DictField(field=IntField())
 
         Simple.drop_collection()
 
         e = Simple()
-        e.mapping['someint'] = 1
+        e.mapping["someint"] = 1
         e.save()
 
         # try creating an invalid mapping
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
-            e.mapping['somestring'] = "abc"
+            e.mapping["somestring"] = "abc"
             e.save()
 
     def test_dictfield_complex(self):
         """Ensure that the dict field can handle the complex types."""
+
         class SettingBase(EmbeddedDocument):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
         class StringSetting(SettingBase):
             value = StringField()
@@ -164,73 +196,76 @@ class TestDictField(MongoDBTestCase):
         Simple.drop_collection()
 
         e = Simple()
-        e.mapping['somestring'] = StringSetting(value='foo')
+        e.mapping["somestring"] = StringSetting(value="foo")
-        e.mapping['someint'] = IntegerSetting(value=42)
+        e.mapping["someint"] = IntegerSetting(value=42)
-        e.mapping['nested_dict'] = {'number': 1, 'string': 'Hi!',
+        e.mapping["nested_dict"] = {
-                                    'float': 1.001,
+            "number": 1,
-                                    'complex': IntegerSetting(value=42),
+            "string": "Hi!",
-                                    'list': [IntegerSetting(value=42),
+            "float": 1.001,
-                                             StringSetting(value='foo')]}
+            "complex": IntegerSetting(value=42),
+            "list": [IntegerSetting(value=42), StringSetting(value="foo")],
+        }
         e.save()
 
         e2 = Simple.objects.get(id=e.id)
-        self.assertIsInstance(e2.mapping['somestring'], StringSetting)
+        assert isinstance(e2.mapping["somestring"], StringSetting)
-        self.assertIsInstance(e2.mapping['someint'], IntegerSetting)
+        assert isinstance(e2.mapping["someint"], IntegerSetting)
 
         # Test querying
-        self.assertEqual(
+        assert Simple.objects.filter(mapping__someint__value=42).count() == 1
-            Simple.objects.filter(mapping__someint__value=42).count(), 1)
+        assert Simple.objects.filter(mapping__nested_dict__number=1).count() == 1
-        self.assertEqual(
+        assert (
-            Simple.objects.filter(mapping__nested_dict__number=1).count(), 1)
+            Simple.objects.filter(mapping__nested_dict__complex__value=42).count() == 1
-        self.assertEqual(
+        )
-            Simple.objects.filter(mapping__nested_dict__complex__value=42).count(), 1)
+        assert (
-        self.assertEqual(
+            Simple.objects.filter(mapping__nested_dict__list__0__value=42).count() == 1
-            Simple.objects.filter(mapping__nested_dict__list__0__value=42).count(), 1)
+        )
-        self.assertEqual(
+        assert (
-            Simple.objects.filter(mapping__nested_dict__list__1__value='foo').count(), 1)
+            Simple.objects.filter(mapping__nested_dict__list__1__value="foo").count()
+            == 1
+        )
 
         # Confirm can update
+        Simple.objects().update(set__mapping={"someint": IntegerSetting(value=10)})
         Simple.objects().update(
-            set__mapping={"someint": IntegerSetting(value=10)})
+            set__mapping__nested_dict__list__1=StringSetting(value="Boo")
-        Simple.objects().update(
+        )
-            set__mapping__nested_dict__list__1=StringSetting(value='Boo'))
+        assert (
-        self.assertEqual(
+            Simple.objects.filter(mapping__nested_dict__list__1__value="foo").count()
-            Simple.objects.filter(mapping__nested_dict__list__1__value='foo').count(), 0)
+            == 0
-        self.assertEqual(
+        )
-            Simple.objects.filter(mapping__nested_dict__list__1__value='Boo').count(), 1)
+        assert (
+            Simple.objects.filter(mapping__nested_dict__list__1__value="Boo").count()
+            == 1
+        )
 
     def test_push_dict(self):
         class MyModel(Document):
             events = ListField(DictField())
 
-        doc = MyModel(events=[{'a': 1}]).save()
+        doc = MyModel(events=[{"a": 1}]).save()
         raw_doc = get_as_pymongo(doc)
-        expected_raw_doc = {
+        expected_raw_doc = {"_id": doc.id, "events": [{"a": 1}]}
-            '_id': doc.id,
+        assert raw_doc == expected_raw_doc
-            'events': [{'a': 1}]
-        }
-        self.assertEqual(raw_doc, expected_raw_doc)
 
         MyModel.objects(id=doc.id).update(push__events={})
         raw_doc = get_as_pymongo(doc)
-        expected_raw_doc = {
+        expected_raw_doc = {"_id": doc.id, "events": [{"a": 1}, {}]}
-            '_id': doc.id,
+        assert raw_doc == expected_raw_doc
-            'events': [{'a': 1}, {}]
-        }
-        self.assertEqual(raw_doc, expected_raw_doc)
 
     def test_ensure_unique_default_instances(self):
         """Ensure that every field has it's own unique default instance."""
+
         class D(Document):
             data = DictField()
             data2 = DictField(default=lambda: {})
 
         d1 = D()
-        d1.data['foo'] = 'bar'
+        d1.data["foo"] = "bar"
-        d1.data2['foo'] = 'bar'
+        d1.data2["foo"] = "bar"
         d2 = D()
-        self.assertEqual(d2.data, {})
+        assert d2.data == {}
-        self.assertEqual(d2.data2, {})
+        assert d2.data2 == {}
 
     def test_dict_field_invalid_dict_value(self):
         class DictFieldTest(Document):
@@ -240,11 +275,13 @@ class TestDictField(MongoDBTestCase):
 
         test = DictFieldTest(dictionary=None)
         test.dictionary  # Just access to test getter
-        self.assertRaises(ValidationError, test.validate)
+        with pytest.raises(ValidationError):
+            test.validate()
 
         test = DictFieldTest(dictionary=False)
         test.dictionary  # Just access to test getter
-        self.assertRaises(ValidationError, test.validate)
+        with pytest.raises(ValidationError):
+            test.validate()
 
     def test_dict_field_raises_validation_error_if_wrongly_assign_embedded_doc(self):
         class DictFieldTest(Document):
@@ -255,31 +292,34 @@ class TestDictField(MongoDBTestCase):
         class Embedded(EmbeddedDocument):
             name = StringField()
 
-        embed = Embedded(name='garbage')
+        embed = Embedded(name="garbage")
         doc = DictFieldTest(dictionary=embed)
-        with self.assertRaises(ValidationError) as ctx_err:
+        with pytest.raises(ValidationError) as exc_info:
             doc.validate()
-        self.assertIn("'dictionary'", str(ctx_err.exception))
+
-        self.assertIn('Only dictionaries may be used in a DictField', str(ctx_err.exception))
+        error_msg = str(exc_info.value)
+        assert "'dictionary'" in error_msg
+        assert "Only dictionaries may be used in a DictField" in error_msg
 
     def test_atomic_update_dict_field(self):
         """Ensure that the entire DictField can be atomically updated."""
+
         class Simple(Document):
             mapping = DictField(field=ListField(IntField(required=True)))
 
         Simple.drop_collection()
 
         e = Simple()
-        e.mapping['someints'] = [1, 2]
+        e.mapping["someints"] = [1, 2]
         e.save()
         e.update(set__mapping={"ints": [3, 4]})
         e.reload()
-        self.assertEqual(BaseDict, type(e.mapping))
+        assert isinstance(e.mapping, BaseDict)
-        self.assertEqual({"ints": [3, 4]}, e.mapping)
+        assert {"ints": [3, 4]} == e.mapping
 
         # try creating an invalid mapping
-        with self.assertRaises(ValueError):
+        with pytest.raises(ValueError):
-            e.update(set__mapping={"somestrings": ["foo", "bar", ]})
+            e.update(set__mapping={"somestrings": ["foo", "bar"]})
 
     def test_dictfield_with_referencefield_complex_nesting_cases(self):
         """Ensure complex nesting inside DictField handles dereferencing of ReferenceField(dbref=True | False)"""
@@ -296,29 +336,33 @@ class TestDictField(MongoDBTestCase):
             mapping5 = DictField(DictField(field=ReferenceField(Doc, dbref=False)))
             mapping6 = DictField(ListField(DictField(ReferenceField(Doc, dbref=True))))
             mapping7 = DictField(ListField(DictField(ReferenceField(Doc, dbref=False))))
-            mapping8 = DictField(ListField(DictField(ListField(ReferenceField(Doc, dbref=True)))))
+            mapping8 = DictField(
-            mapping9 = DictField(ListField(DictField(ListField(ReferenceField(Doc, dbref=False)))))
+                ListField(DictField(ListField(ReferenceField(Doc, dbref=True))))
+            )
+            mapping9 = DictField(
+                ListField(DictField(ListField(ReferenceField(Doc, dbref=False))))
+            )
 
         Doc.drop_collection()
         Simple.drop_collection()
 
-        d = Doc(s='aa').save()
+        d = Doc(s="aa").save()
         e = Simple()
-        e.mapping0['someint'] = e.mapping1['someint'] = d
+        e.mapping0["someint"] = e.mapping1["someint"] = d
-        e.mapping2['someint'] = e.mapping3['someint'] = [d]
+        e.mapping2["someint"] = e.mapping3["someint"] = [d]
-        e.mapping4['someint'] = e.mapping5['someint'] = {'d': d}
+        e.mapping4["someint"] = e.mapping5["someint"] = {"d": d}
-        e.mapping6['someint'] = e.mapping7['someint'] = [{'d': d}]
+        e.mapping6["someint"] = e.mapping7["someint"] = [{"d": d}]
-        e.mapping8['someint'] = e.mapping9['someint'] = [{'d': [d]}]
+        e.mapping8["someint"] = e.mapping9["someint"] = [{"d": [d]}]
         e.save()
 
         s = Simple.objects.first()
-        self.assertIsInstance(s.mapping0['someint'], Doc)
+        assert isinstance(s.mapping0["someint"], Doc)
-        self.assertIsInstance(s.mapping1['someint'], Doc)
+        assert isinstance(s.mapping1["someint"], Doc)
-        self.assertIsInstance(s.mapping2['someint'][0], Doc)
+        assert isinstance(s.mapping2["someint"][0], Doc)
-        self.assertIsInstance(s.mapping3['someint'][0], Doc)
+        assert isinstance(s.mapping3["someint"][0], Doc)
-        self.assertIsInstance(s.mapping4['someint']['d'], Doc)
+        assert isinstance(s.mapping4["someint"]["d"], Doc)
-        self.assertIsInstance(s.mapping5['someint']['d'], Doc)
+        assert isinstance(s.mapping5["someint"]["d"], Doc)
-        self.assertIsInstance(s.mapping6['someint'][0]['d'], Doc)
+        assert isinstance(s.mapping6["someint"][0]["d"], Doc)
-        self.assertIsInstance(s.mapping7['someint'][0]['d'], Doc)
+        assert isinstance(s.mapping7["someint"][0]["d"], Doc)
-        self.assertIsInstance(s.mapping8['someint'][0]['d'][0], Doc)
+        assert isinstance(s.mapping8["someint"][0]["d"][0], Doc)
-        self.assertIsInstance(s.mapping9['someint'][0]['d'][0], Doc)
+        assert isinstance(s.mapping9["someint"][0]["d"][0], Doc)

tests/fields/test_email_field.py

@@ -1,9 +1,9 @@
 # -*- coding: utf-8 -*-
 import sys
-from unittest import SkipTest
+
+import pytest
 
 from mongoengine import *
-
 from tests.utils import MongoDBTestCase
 
 
@@ -12,52 +12,52 @@ class TestEmailField(MongoDBTestCase):
         class User(Document):
             email = EmailField()
 
-        user = User(email='ross@example.com')
+        user = User(email="ross@example.com")
         user.validate()
 
-        user = User(email='ross@example.co.uk')
+        user = User(email="ross@example.co.uk")
         user.validate()
 
-        user = User(email=('Kofq@rhom0e4klgauOhpbpNdogawnyIKvQS0wk2mjqrgGQ5S'
+        user = User(
-                           'aJIazqqWkm7.net'))
+            email=("Kofq@rhom0e4klgauOhpbpNdogawnyIKvQS0wk2mjqrgGQ5SaJIazqqWkm7.net")
+        )
         user.validate()
 
-        user = User(email='new-tld@example.technology')
+        user = User(email="new-tld@example.technology")
         user.validate()
 
-        user = User(email='ross@example.com.')
+        user = User(email="ross@example.com.")
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         # unicode domain
-        user = User(email=u'user@пример.рф')
+        user = User(email=u"user@пример.рф")
         user.validate()
 
         # invalid unicode domain
-        user = User(email=u'user@пример')
+        user = User(email=u"user@пример")
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         # invalid data type
         user = User(email=123)
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
     def test_email_field_unicode_user(self):
-        # Don't run this test on pypy3, which doesn't support unicode regex:
-        # https://bitbucket.org/pypy/pypy/issues/1821/regular-expression-doesnt-find-unicode
-        if sys.version_info[:2] == (3, 2):
-            raise SkipTest('unicode email addresses are not supported on PyPy 3')
-
         class User(Document):
             email = EmailField()
 
         # unicode user shouldn't validate by default...
-        user = User(email=u'Dörte@Sörensen.example.com')
+        user = User(email=u"Dörte@Sörensen.example.com")
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         # ...but it should be fine with allow_utf8_user set to True
         class User(Document):
             email = EmailField(allow_utf8_user=True)
 
-        user = User(email=u'Dörte@Sörensen.example.com')
+        user = User(email=u"Dörte@Sörensen.example.com")
         user.validate()
 
     def test_email_field_domain_whitelist(self):
@@ -65,43 +65,48 @@ class TestEmailField(MongoDBTestCase):
             email = EmailField()
 
         # localhost domain shouldn't validate by default...
-        user = User(email='me@localhost')
+        user = User(email="me@localhost")
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         # ...but it should be fine if it's whitelisted
         class User(Document):
-            email = EmailField(domain_whitelist=['localhost'])
+            email = EmailField(domain_whitelist=["localhost"])
 
-        user = User(email='me@localhost')
+        user = User(email="me@localhost")
         user.validate()
 
     def test_email_domain_validation_fails_if_invalid_idn(self):
         class User(Document):
             email = EmailField()
 
-        invalid_idn = '.google.com'
+        invalid_idn = ".google.com"
-        user = User(email='me@%s' % invalid_idn)
+        user = User(email="me@%s" % invalid_idn)
-        with self.assertRaises(ValidationError) as ctx_err:
+
+        with pytest.raises(ValidationError) as exc_info:
             user.validate()
-        self.assertIn("domain failed IDN encoding", str(ctx_err.exception))
+        assert "domain failed IDN encoding" in str(exc_info.value)
 
     def test_email_field_ip_domain(self):
         class User(Document):
             email = EmailField()
 
-        valid_ipv4 = 'email@[127.0.0.1]'
+        valid_ipv4 = "email@[127.0.0.1]"
-        valid_ipv6 = 'email@[2001:dB8::1]'
+        valid_ipv6 = "email@[2001:dB8::1]"
-        invalid_ip = 'email@[324.0.0.1]'
+        invalid_ip = "email@[324.0.0.1]"
 
         # IP address as a domain shouldn't validate by default...
         user = User(email=valid_ipv4)
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         user = User(email=valid_ipv6)
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         user = User(email=invalid_ip)
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         # ...but it should be fine with allow_ip_domain set to True
         class User(Document):
@@ -115,16 +120,18 @@ class TestEmailField(MongoDBTestCase):
 
         # invalid IP should still fail validation
         user = User(email=invalid_ip)
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
     def test_email_field_honors_regex(self):
         class User(Document):
-            email = EmailField(regex=r'\w+@example.com')
+            email = EmailField(regex=r"\w+@example.com")
 
         # Fails regex validation
-        user = User(email='me@foo.com')
+        user = User(email="me@foo.com")
-        self.assertRaises(ValidationError, user.validate)
+        with pytest.raises(ValidationError):
+            user.validate()
 
         # Passes regex validation
-        user = User(email='me@example.com')
+        user = User(email="me@example.com")
-        self.assertIsNone(user.validate())
+        assert user.validate() is None

tests/fields/test_embedded_document_field.py

@@ -1,7 +1,18 @@
 # -*- coding: utf-8 -*-
-from mongoengine import Document, StringField, ValidationError, EmbeddedDocument, EmbeddedDocumentField, \
+import pytest
-    InvalidQueryError, LookUpError, IntField, GenericEmbeddedDocumentField, ListField, EmbeddedDocumentListField, \
+
-    ReferenceField
+from mongoengine import (
+    Document,
+    EmbeddedDocument,
+    EmbeddedDocumentField,
+    GenericEmbeddedDocumentField,
+    IntField,
+    InvalidQueryError,
+    ListField,
+    LookUpError,
+    StringField,
+    ValidationError,
+)
 
 from tests.utils import MongoDBTestCase
 
@@ -12,37 +23,41 @@ class TestEmbeddedDocumentField(MongoDBTestCase):
             name = StringField()
 
         field = EmbeddedDocumentField(MyDoc)
-        self.assertEqual(field.document_type_obj, MyDoc)
+        assert field.document_type_obj == MyDoc
 
-        field2 = EmbeddedDocumentField('MyDoc')
+        field2 = EmbeddedDocumentField("MyDoc")
-        self.assertEqual(field2.document_type_obj, 'MyDoc')
+        assert field2.document_type_obj == "MyDoc"
 
     def test___init___throw_error_if_document_type_is_not_EmbeddedDocument(self):
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
             EmbeddedDocumentField(dict)
 
     def test_document_type_throw_error_if_not_EmbeddedDocument_subclass(self):
-
         class MyDoc(Document):
             name = StringField()
 
-        emb = EmbeddedDocumentField('MyDoc')
+        emb = EmbeddedDocumentField("MyDoc")
-        with self.assertRaises(ValidationError) as ctx:
+        with pytest.raises(ValidationError) as exc_info:
             emb.document_type
-        self.assertIn('Invalid embedded document class provided to an EmbeddedDocumentField', str(ctx.exception))
+        assert (
+            "Invalid embedded document class provided to an EmbeddedDocumentField"
+            in str(exc_info.value)
+        )
 
     def test_embedded_document_field_only_allow_subclasses_of_embedded_document(self):
         # Relates to #1661
         class MyDoc(Document):
             name = StringField()
 
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
+
             class MyFailingDoc(Document):
                 emb = EmbeddedDocumentField(MyDoc)
 
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
+
             class MyFailingdoc2(Document):
-                emb = EmbeddedDocumentField('MyDoc')
+                emb = EmbeddedDocumentField("MyDoc")
 
     def test_query_embedded_document_attribute(self):
         class AdminSettings(EmbeddedDocument):
@@ -55,34 +70,31 @@ class TestEmbeddedDocumentField(MongoDBTestCase):
 
         Person.drop_collection()
 
-        p = Person(
+        p = Person(settings=AdminSettings(foo1="bar1", foo2="bar2"), name="John").save()
-            settings=AdminSettings(foo1='bar1', foo2='bar2'),
-            name='John',
-        ).save()
 
         # Test non exiting attribute
-        with self.assertRaises(InvalidQueryError) as ctx_err:
+        with pytest.raises(InvalidQueryError) as exc_info:
-            Person.objects(settings__notexist='bar').first()
+            Person.objects(settings__notexist="bar").first()
-        self.assertEqual(unicode(ctx_err.exception), u'Cannot resolve field "notexist"')
+        assert str(exc_info.value) == u'Cannot resolve field "notexist"'
 
-        with self.assertRaises(LookUpError):
+        with pytest.raises(LookUpError):
-            Person.objects.only('settings.notexist')
+            Person.objects.only("settings.notexist")
 
         # Test existing attribute
-        self.assertEqual(Person.objects(settings__foo1='bar1').first().id, p.id)
+        assert Person.objects(settings__foo1="bar1").first().id == p.id
-        only_p = Person.objects.only('settings.foo1').first()
+        only_p = Person.objects.only("settings.foo1").first()
-        self.assertEqual(only_p.settings.foo1, p.settings.foo1)
+        assert only_p.settings.foo1 == p.settings.foo1
-        self.assertIsNone(only_p.settings.foo2)
+        assert only_p.settings.foo2 is None
-        self.assertIsNone(only_p.name)
+        assert only_p.name is None
 
-        exclude_p = Person.objects.exclude('settings.foo1').first()
+        exclude_p = Person.objects.exclude("settings.foo1").first()
-        self.assertIsNone(exclude_p.settings.foo1)
+        assert exclude_p.settings.foo1 is None
-        self.assertEqual(exclude_p.settings.foo2, p.settings.foo2)
+        assert exclude_p.settings.foo2 == p.settings.foo2
-        self.assertEqual(exclude_p.name, p.name)
+        assert exclude_p.name == p.name
 
     def test_query_embedded_document_attribute_with_inheritance(self):
         class BaseSettings(EmbeddedDocument):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
             base_foo = StringField()
 
         class AdminSettings(BaseSettings):
@@ -93,26 +105,26 @@ class TestEmbeddedDocumentField(MongoDBTestCase):
 
         Person.drop_collection()
 
-        p = Person(settings=AdminSettings(base_foo='basefoo', sub_foo='subfoo'))
+        p = Person(settings=AdminSettings(base_foo="basefoo", sub_foo="subfoo"))
         p.save()
 
         # Test non exiting attribute
-        with self.assertRaises(InvalidQueryError) as ctx_err:
+        with pytest.raises(InvalidQueryError) as exc_info:
-            self.assertEqual(Person.objects(settings__notexist='bar').first().id, p.id)
+            assert Person.objects(settings__notexist="bar").first().id == p.id
-        self.assertEqual(unicode(ctx_err.exception), u'Cannot resolve field "notexist"')
+        assert str(exc_info.value) == u'Cannot resolve field "notexist"'
 
         # Test existing attribute
-        self.assertEqual(Person.objects(settings__base_foo='basefoo').first().id, p.id)
+        assert Person.objects(settings__base_foo="basefoo").first().id == p.id
-        self.assertEqual(Person.objects(settings__sub_foo='subfoo').first().id, p.id)
+        assert Person.objects(settings__sub_foo="subfoo").first().id == p.id
 
-        only_p = Person.objects.only('settings.base_foo', 'settings._cls').first()
+        only_p = Person.objects.only("settings.base_foo", "settings._cls").first()
-        self.assertEqual(only_p.settings.base_foo, 'basefoo')
+        assert only_p.settings.base_foo == "basefoo"
-        self.assertIsNone(only_p.settings.sub_foo)
+        assert only_p.settings.sub_foo is None
 
     def test_query_list_embedded_document_with_inheritance(self):
         class Post(EmbeddedDocument):
             title = StringField(max_length=120, required=True)
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
         class TextPost(Post):
             content = StringField()
@@ -123,22 +135,21 @@ class TestEmbeddedDocumentField(MongoDBTestCase):
         class Record(Document):
             posts = ListField(EmbeddedDocumentField(Post))
 
-        record_movie = Record(posts=[MoviePost(author='John', title='foo')]).save()
+        record_movie = Record(posts=[MoviePost(author="John", title="foo")]).save()
-        record_text = Record(posts=[TextPost(content='a', title='foo')]).save()
+        record_text = Record(posts=[TextPost(content="a", title="foo")]).save()
 
         records = list(Record.objects(posts__author=record_movie.posts[0].author))
-        self.assertEqual(len(records), 1)
+        assert len(records) == 1
-        self.assertEqual(records[0].id, record_movie.id)
+        assert records[0].id == record_movie.id
 
         records = list(Record.objects(posts__content=record_text.posts[0].content))
-        self.assertEqual(len(records), 1)
+        assert len(records) == 1
-        self.assertEqual(records[0].id, record_text.id)
+        assert records[0].id == record_text.id
 
-        self.assertEqual(Record.objects(posts__title='foo').count(), 2)
+        assert Record.objects(posts__title="foo").count() == 2
 
 
 class TestGenericEmbeddedDocumentField(MongoDBTestCase):
-
     def test_generic_embedded_document(self):
         class Car(EmbeddedDocument):
             name = StringField()
@@ -153,21 +164,22 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
 
         Person.drop_collection()
 
-        person = Person(name='Test User')
+        person = Person(name="Test User")
-        person.like = Car(name='Fiat')
+        person.like = Car(name="Fiat")
         person.save()
 
         person = Person.objects.first()
-        self.assertIsInstance(person.like, Car)
+        assert isinstance(person.like, Car)
 
         person.like = Dish(food="arroz", number=15)
         person.save()
 
         person = Person.objects.first()
-        self.assertIsInstance(person.like, Dish)
+        assert isinstance(person.like, Dish)
 
     def test_generic_embedded_document_choices(self):
         """Ensure you can limit GenericEmbeddedDocument choices."""
+
         class Car(EmbeddedDocument):
             name = StringField()
 
@@ -181,20 +193,22 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
 
         Person.drop_collection()
 
-        person = Person(name='Test User')
+        person = Person(name="Test User")
-        person.like = Car(name='Fiat')
+        person.like = Car(name="Fiat")
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
 
         person.like = Dish(food="arroz", number=15)
         person.save()
 
         person = Person.objects.first()
-        self.assertIsInstance(person.like, Dish)
+        assert isinstance(person.like, Dish)
 
     def test_generic_list_embedded_document_choices(self):
         """Ensure you can limit GenericEmbeddedDocument choices inside
         a list field.
         """
+
         class Car(EmbeddedDocument):
             name = StringField()
 
@@ -208,39 +222,38 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
 
         Person.drop_collection()
 
-        person = Person(name='Test User')
+        person = Person(name="Test User")
-        person.likes = [Car(name='Fiat')]
+        person.likes = [Car(name="Fiat")]
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
 
         person.likes = [Dish(food="arroz", number=15)]
         person.save()
 
         person = Person.objects.first()
-        self.assertIsInstance(person.likes[0], Dish)
+        assert isinstance(person.likes[0], Dish)
 
     def test_choices_validation_documents(self):
         """
         Ensure fields with document choices validate given a valid choice.
         """
+
         class UserComments(EmbeddedDocument):
             author = StringField()
             message = StringField()
 
         class BlogPost(Document):
-            comments = ListField(
+            comments = ListField(GenericEmbeddedDocumentField(choices=(UserComments,)))
-                GenericEmbeddedDocumentField(choices=(UserComments,))
-            )
 
         # Ensure Validation Passes
-        BlogPost(comments=[
+        BlogPost(comments=[UserComments(author="user2", message="message2")]).save()
-            UserComments(author='user2', message='message2'),
-        ]).save()
 
     def test_choices_validation_documents_invalid(self):
         """
         Ensure fields with document choices validate given an invalid choice.
         This should throw a ValidationError exception.
         """
+
         class UserComments(EmbeddedDocument):
             author = StringField()
             message = StringField()
@@ -250,31 +263,30 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
             message = StringField()
 
         class BlogPost(Document):
-            comments = ListField(
+            comments = ListField(GenericEmbeddedDocumentField(choices=(UserComments,)))
-                GenericEmbeddedDocumentField(choices=(UserComments,))
-            )
 
         # Single Entry Failure
-        post = BlogPost(comments=[
+        post = BlogPost(comments=[ModeratorComments(author="mod1", message="message1")])
-            ModeratorComments(author='mod1', message='message1'),
+        with pytest.raises(ValidationError):
-        ])
+            post.save()
-        self.assertRaises(ValidationError, post.save)
 
         # Mixed Entry Failure
-        post = BlogPost(comments=[
+        post = BlogPost(
-            ModeratorComments(author='mod1', message='message1'),
+            comments=[
-            UserComments(author='user2', message='message2'),
+                ModeratorComments(author="mod1", message="message1"),
-        ])
+                UserComments(author="user2", message="message2"),
-        self.assertRaises(ValidationError, post.save)
+            ]
+        )
+        with pytest.raises(ValidationError):
+            post.save()
 
     def test_choices_validation_documents_inheritance(self):
         """
         Ensure fields with document choices validate given subclass of choice.
         """
+
         class Comments(EmbeddedDocument):
-            meta = {
+            meta = {"abstract": True}
-                'abstract': True
-            }
             author = StringField()
             message = StringField()
 
@@ -282,14 +294,10 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
             pass
 
         class BlogPost(Document):
-            comments = ListField(
+            comments = ListField(GenericEmbeddedDocumentField(choices=(Comments,)))
-                GenericEmbeddedDocumentField(choices=(Comments,))
-            )
 
         # Save Valid EmbeddedDocument Type
-        BlogPost(comments=[
+        BlogPost(comments=[UserComments(author="user2", message="message2")]).save()
-            UserComments(author='user2', message='message2'),
-        ]).save()
 
     def test_query_generic_embedded_document_attribute(self):
         class AdminSettings(EmbeddedDocument):
@@ -299,28 +307,30 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
             foo2 = StringField()
 
         class Person(Document):
-            settings = GenericEmbeddedDocumentField(choices=(AdminSettings, NonAdminSettings))
+            settings = GenericEmbeddedDocumentField(
+                choices=(AdminSettings, NonAdminSettings)
+            )
 
         Person.drop_collection()
 
-        p1 = Person(settings=AdminSettings(foo1='bar1')).save()
+        p1 = Person(settings=AdminSettings(foo1="bar1")).save()
-        p2 = Person(settings=NonAdminSettings(foo2='bar2')).save()
+        p2 = Person(settings=NonAdminSettings(foo2="bar2")).save()
 
         # Test non exiting attribute
-        with self.assertRaises(InvalidQueryError) as ctx_err:
+        with pytest.raises(InvalidQueryError) as exc_info:
-            Person.objects(settings__notexist='bar').first()
+            Person.objects(settings__notexist="bar").first()
-        self.assertEqual(unicode(ctx_err.exception), u'Cannot resolve field "notexist"')
+        assert str(exc_info.value) == u'Cannot resolve field "notexist"'
 
-        with self.assertRaises(LookUpError):
+        with pytest.raises(LookUpError):
-            Person.objects.only('settings.notexist')
+            Person.objects.only("settings.notexist")
 
         # Test existing attribute
-        self.assertEqual(Person.objects(settings__foo1='bar1').first().id, p1.id)
+        assert Person.objects(settings__foo1="bar1").first().id == p1.id
-        self.assertEqual(Person.objects(settings__foo2='bar2').first().id, p2.id)
+        assert Person.objects(settings__foo2="bar2").first().id == p2.id
 
     def test_query_generic_embedded_document_attribute_with_inheritance(self):
         class BaseSettings(EmbeddedDocument):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
             base_foo = StringField()
 
         class AdminSettings(BaseSettings):
@@ -331,14 +341,14 @@ class TestGenericEmbeddedDocumentField(MongoDBTestCase):
 
         Person.drop_collection()
 
-        p = Person(settings=AdminSettings(base_foo='basefoo', sub_foo='subfoo'))
+        p = Person(settings=AdminSettings(base_foo="basefoo", sub_foo="subfoo"))
         p.save()
 
         # Test non exiting attribute
-        with self.assertRaises(InvalidQueryError) as ctx_err:
+        with pytest.raises(InvalidQueryError) as exc_info:
-            self.assertEqual(Person.objects(settings__notexist='bar').first().id, p.id)
+            assert Person.objects(settings__notexist="bar").first().id == p.id
-        self.assertEqual(unicode(ctx_err.exception), u'Cannot resolve field "notexist"')
+        assert str(exc_info.value) == u'Cannot resolve field "notexist"'
 
         # Test existing attribute
-        self.assertEqual(Person.objects(settings__base_foo='basefoo').first().id, p.id)
+        assert Person.objects(settings__base_foo="basefoo").first().id == p.id
-        self.assertEqual(Person.objects(settings__sub_foo='subfoo').first().id, p.id)
+        assert Person.objects(settings__sub_foo="subfoo").first().id == p.id

tests/fields/test_file_field.py

@@ -1,49 +1,51 @@
 # -*- coding: utf-8 -*-
 import copy
 import os
-import unittest
 import tempfile
+import unittest
+from io import BytesIO
 
 import gridfs
-import six
+import pytest
 
-from nose.plugins.skip import SkipTest
 from mongoengine import *
 from mongoengine.connection import get_db
-from mongoengine.python_support import StringIO
 
 try:
     from PIL import Image
+
     HAS_PIL = True
 except ImportError:
     HAS_PIL = False
 
 from tests.utils import MongoDBTestCase
 
-TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__), 'mongoengine.png')
+require_pil = pytest.mark.skipif(not HAS_PIL, reason="PIL not installed")
-TEST_IMAGE2_PATH = os.path.join(os.path.dirname(__file__), 'mongodb_leaf.png')
+
+TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__), "mongoengine.png")
+TEST_IMAGE2_PATH = os.path.join(os.path.dirname(__file__), "mongodb_leaf.png")
 
 
 def get_file(path):
     """Use a BytesIO instead of a file to allow
     to have a one-liner and avoid that the file remains opened"""
-    bytes_io = StringIO()
+    bytes_io = BytesIO()
-    with open(path, 'rb') as f:
+    with open(path, "rb") as f:
         bytes_io.write(f.read())
     bytes_io.seek(0)
     return bytes_io
 
 
-class FileTest(MongoDBTestCase):
+class TestFileField(MongoDBTestCase):
-
     def tearDown(self):
-        self.db.drop_collection('fs.files')
+        self.db.drop_collection("fs.files")
-        self.db.drop_collection('fs.chunks')
+        self.db.drop_collection("fs.chunks")
 
     def test_file_field_optional(self):
         # Make sure FileField is optional and not required
         class DemoFile(Document):
             the_file = FileField()
+
         DemoFile.objects.create()
 
     def test_file_fields(self):
@@ -55,18 +57,21 @@ class FileTest(MongoDBTestCase):
 
         PutFile.drop_collection()
 
-        text = six.b('Hello, World!')
+        text = "Hello, World!".encode("latin-1")
-        content_type = 'text/plain'
+        content_type = "text/plain"
 
         putfile = PutFile()
         putfile.the_file.put(text, content_type=content_type, filename="hello")
         putfile.save()
 
         result = PutFile.objects.first()
-        self.assertEqual(putfile, result)
+        assert putfile == result
-        self.assertEqual("%s" % result.the_file, "<GridFSProxy: hello (%s)>" % result.the_file.grid_id)
+        assert (
-        self.assertEqual(result.the_file.read(), text)
+            "%s" % result.the_file
-        self.assertEqual(result.the_file.content_type, content_type)
+            == "<GridFSProxy: hello (%s)>" % result.the_file.grid_id
+        )
+        assert result.the_file.read() == text
+        assert result.the_file.content_type == content_type
         result.the_file.delete()  # Remove file from GridFS
         PutFile.objects.delete()
 
@@ -74,29 +79,30 @@ class FileTest(MongoDBTestCase):
         PutFile.drop_collection()
 
         putfile = PutFile()
-        putstring = StringIO()
+        putstring = BytesIO()
         putstring.write(text)
         putstring.seek(0)
         putfile.the_file.put(putstring, content_type=content_type)
         putfile.save()
 
         result = PutFile.objects.first()
-        self.assertEqual(putfile, result)
+        assert putfile == result
-        self.assertEqual(result.the_file.read(), text)
+        assert result.the_file.read() == text
-        self.assertEqual(result.the_file.content_type, content_type)
+        assert result.the_file.content_type == content_type
         result.the_file.delete()
 
     def test_file_fields_stream(self):
         """Ensure that file fields can be written to and their data retrieved
         """
+
         class StreamFile(Document):
             the_file = FileField()
 
         StreamFile.drop_collection()
 
-        text = six.b('Hello, World!')
+        text = "Hello, World!".encode("latin-1")
-        more_text = six.b('Foo Bar')
+        more_text = "Foo Bar".encode("latin-1")
-        content_type = 'text/plain'
+        content_type = "text/plain"
 
         streamfile = StreamFile()
         streamfile.the_file.new_file(content_type=content_type)
@@ -106,32 +112,32 @@ class FileTest(MongoDBTestCase):
         streamfile.save()
 
         result = StreamFile.objects.first()
-        self.assertEqual(streamfile, result)
+        assert streamfile == result
-        self.assertEqual(result.the_file.read(), text + more_text)
+        assert result.the_file.read() == text + more_text
-        self.assertEqual(result.the_file.content_type, content_type)
+        assert result.the_file.content_type == content_type
         result.the_file.seek(0)
-        self.assertEqual(result.the_file.tell(), 0)
+        assert result.the_file.tell() == 0
-        self.assertEqual(result.the_file.read(len(text)), text)
+        assert result.the_file.read(len(text)) == text
-        self.assertEqual(result.the_file.tell(), len(text))
+        assert result.the_file.tell() == len(text)
-        self.assertEqual(result.the_file.read(len(more_text)), more_text)
+        assert result.the_file.read(len(more_text)) == more_text
-        self.assertEqual(result.the_file.tell(), len(text + more_text))
+        assert result.the_file.tell() == len(text + more_text)
         result.the_file.delete()
 
         # Ensure deleted file returns None
-        self.assertTrue(result.the_file.read() is None)
+        assert result.the_file.read() is None
 
     def test_file_fields_stream_after_none(self):
         """Ensure that a file field can be written to after it has been saved as
         None
         """
+
         class StreamFile(Document):
             the_file = FileField()
 
         StreamFile.drop_collection()
 
-        text = six.b('Hello, World!')
+        text = "Hello, World!".encode("latin-1")
-        more_text = six.b('Foo Bar')
+        more_text = "Foo Bar".encode("latin-1")
-        content_type = 'text/plain'
 
         streamfile = StreamFile()
         streamfile.save()
@@ -142,27 +148,26 @@ class FileTest(MongoDBTestCase):
         streamfile.save()
 
         result = StreamFile.objects.first()
-        self.assertEqual(streamfile, result)
+        assert streamfile == result
-        self.assertEqual(result.the_file.read(), text + more_text)
+        assert result.the_file.read() == text + more_text
-        # self.assertEqual(result.the_file.content_type, content_type)
+        # assert result.the_file.content_type == content_type
         result.the_file.seek(0)
-        self.assertEqual(result.the_file.tell(), 0)
+        assert result.the_file.tell() == 0
-        self.assertEqual(result.the_file.read(len(text)), text)
+        assert result.the_file.read(len(text)) == text
-        self.assertEqual(result.the_file.tell(), len(text))
+        assert result.the_file.tell() == len(text)
-        self.assertEqual(result.the_file.read(len(more_text)), more_text)
+        assert result.the_file.read(len(more_text)) == more_text
-        self.assertEqual(result.the_file.tell(), len(text + more_text))
+        assert result.the_file.tell() == len(text + more_text)
         result.the_file.delete()
 
         # Ensure deleted file returns None
-        self.assertTrue(result.the_file.read() is None)
+        assert result.the_file.read() is None
 
     def test_file_fields_set(self):
-
         class SetFile(Document):
             the_file = FileField()
 
-        text = six.b('Hello, World!')
+        text = "Hello, World!".encode("latin-1")
-        more_text = six.b('Foo Bar')
+        more_text = "Foo Bar".encode("latin-1")
 
         SetFile.drop_collection()
 
@@ -171,27 +176,26 @@ class FileTest(MongoDBTestCase):
         setfile.save()
 
         result = SetFile.objects.first()
-        self.assertEqual(setfile, result)
+        assert setfile == result
-        self.assertEqual(result.the_file.read(), text)
+        assert result.the_file.read() == text
 
         # Try replacing file with new one
         result.the_file.replace(more_text)
         result.save()
 
         result = SetFile.objects.first()
-        self.assertEqual(setfile, result)
+        assert setfile == result
-        self.assertEqual(result.the_file.read(), more_text)
+        assert result.the_file.read() == more_text
         result.the_file.delete()
 
     def test_file_field_no_default(self):
-
         class GridDocument(Document):
             the_file = FileField()
 
         GridDocument.drop_collection()
 
         with tempfile.TemporaryFile() as f:
-            f.write(six.b("Hello World!"))
+            f.write("Hello World!".encode("latin-1"))
             f.flush()
 
             # Test without default
@@ -199,34 +203,35 @@ class FileTest(MongoDBTestCase):
             doc_a.save()
 
             doc_b = GridDocument.objects.with_id(doc_a.id)
-            doc_b.the_file.replace(f, filename='doc_b')
+            doc_b.the_file.replace(f, filename="doc_b")
             doc_b.save()
-            self.assertNotEqual(doc_b.the_file.grid_id, None)
+            assert doc_b.the_file.grid_id is not None
 
             # Test it matches
             doc_c = GridDocument.objects.with_id(doc_b.id)
-            self.assertEqual(doc_b.the_file.grid_id, doc_c.the_file.grid_id)
+            assert doc_b.the_file.grid_id == doc_c.the_file.grid_id
 
             # Test with default
-            doc_d = GridDocument(the_file=six.b(''))
+            doc_d = GridDocument(the_file="".encode("latin-1"))
             doc_d.save()
 
             doc_e = GridDocument.objects.with_id(doc_d.id)
-            self.assertEqual(doc_d.the_file.grid_id, doc_e.the_file.grid_id)
+            assert doc_d.the_file.grid_id == doc_e.the_file.grid_id
 
-            doc_e.the_file.replace(f, filename='doc_e')
+            doc_e.the_file.replace(f, filename="doc_e")
             doc_e.save()
 
             doc_f = GridDocument.objects.with_id(doc_e.id)
-            self.assertEqual(doc_e.the_file.grid_id, doc_f.the_file.grid_id)
+            assert doc_e.the_file.grid_id == doc_f.the_file.grid_id
 
         db = GridDocument._get_db()
         grid_fs = gridfs.GridFS(db)
-        self.assertEqual(['doc_b', 'doc_e'], grid_fs.list())
+        assert ["doc_b", "doc_e"] == grid_fs.list()
 
     def test_file_uniqueness(self):
         """Ensure that each instance of a FileField is unique
         """
+
         class TestFile(Document):
             name = StringField()
             the_file = FileField()
@@ -234,15 +239,15 @@ class FileTest(MongoDBTestCase):
         # First instance
         test_file = TestFile()
         test_file.name = "Hello, World!"
-        test_file.the_file.put(six.b('Hello, World!'))
+        test_file.the_file.put("Hello, World!".encode("latin-1"))
         test_file.save()
 
         # Second instance
         test_file_dupe = TestFile()
         data = test_file_dupe.the_file.read()  # Should be None
 
-        self.assertNotEqual(test_file.name, test_file_dupe.name)
+        assert test_file.name != test_file_dupe.name
-        self.assertNotEqual(test_file.the_file.read(), data)
+        assert test_file.the_file.read() != data
 
         TestFile.drop_collection()
 
@@ -255,61 +260,68 @@ class FileTest(MongoDBTestCase):
             photo = FileField()
 
         Animal.drop_collection()
-        marmot = Animal(genus='Marmota', family='Sciuridae')
+        marmot = Animal(genus="Marmota", family="Sciuridae")
 
         marmot_photo_content = get_file(TEST_IMAGE_PATH)  # Retrieve a photo from disk
-        marmot.photo.put(marmot_photo_content, content_type='image/jpeg', foo='bar')
+        marmot.photo.put(marmot_photo_content, content_type="image/jpeg", foo="bar")
         marmot.photo.close()
         marmot.save()
 
         marmot = Animal.objects.get()
-        self.assertEqual(marmot.photo.content_type, 'image/jpeg')
+        assert marmot.photo.content_type == "image/jpeg"
-        self.assertEqual(marmot.photo.foo, 'bar')
+        assert marmot.photo.foo == "bar"
 
     def test_file_reassigning(self):
         class TestFile(Document):
             the_file = FileField()
+
         TestFile.drop_collection()
 
         test_file = TestFile(the_file=get_file(TEST_IMAGE_PATH)).save()
-        self.assertEqual(test_file.the_file.get().length, 8313)
+        assert test_file.the_file.get().length == 8313
 
         test_file = TestFile.objects.first()
         test_file.the_file = get_file(TEST_IMAGE2_PATH)
         test_file.save()
-        self.assertEqual(test_file.the_file.get().length, 4971)
+        assert test_file.the_file.get().length == 4971
 
     def test_file_boolean(self):
         """Ensure that a boolean test of a FileField indicates its presence
         """
+
         class TestFile(Document):
             the_file = FileField()
+
         TestFile.drop_collection()
 
         test_file = TestFile()
-        self.assertFalse(bool(test_file.the_file))
+        assert not bool(test_file.the_file)
-        test_file.the_file.put(six.b('Hello, World!'), content_type='text/plain')
+        test_file.the_file.put(
+            "Hello, World!".encode("latin-1"), content_type="text/plain"
+        )
         test_file.save()
-        self.assertTrue(bool(test_file.the_file))
+        assert bool(test_file.the_file)
 
         test_file = TestFile.objects.first()
-        self.assertEqual(test_file.the_file.content_type, "text/plain")
+        assert test_file.the_file.content_type == "text/plain"
 
     def test_file_cmp(self):
         """Test comparing against other types"""
+
         class TestFile(Document):
             the_file = FileField()
 
         test_file = TestFile()
-        self.assertNotIn(test_file.the_file, [{"test": 1}])
+        assert test_file.the_file not in [{"test": 1}]
 
     def test_file_disk_space(self):
         """ Test disk space usage when we delete/replace a file """
+
         class TestFile(Document):
             the_file = FileField()
 
-        text = six.b('Hello, World!')
+        text = "Hello, World!".encode("latin-1")
-        content_type = 'text/plain'
+        content_type = "text/plain"
 
         testfile = TestFile()
         testfile.the_file.put(text, content_type=content_type, filename="hello")
@@ -320,16 +332,16 @@ class FileTest(MongoDBTestCase):
 
         files = db.fs.files.find()
         chunks = db.fs.chunks.find()
-        self.assertEqual(len(list(files)), 1)
+        assert len(list(files)) == 1
-        self.assertEqual(len(list(chunks)), 1)
+        assert len(list(chunks)) == 1
 
         # Deleting the docoument should delete the files
         testfile.delete()
 
         files = db.fs.files.find()
         chunks = db.fs.chunks.find()
-        self.assertEqual(len(list(files)), 0)
+        assert len(list(files)) == 0
-        self.assertEqual(len(list(chunks)), 0)
+        assert len(list(chunks)) == 0
 
         # Test case where we don't store a file in the first place
         testfile = TestFile()
@@ -337,48 +349,46 @@ class FileTest(MongoDBTestCase):
 
         files = db.fs.files.find()
         chunks = db.fs.chunks.find()
-        self.assertEqual(len(list(files)), 0)
+        assert len(list(files)) == 0
-        self.assertEqual(len(list(chunks)), 0)
+        assert len(list(chunks)) == 0
 
         testfile.delete()
 
         files = db.fs.files.find()
         chunks = db.fs.chunks.find()
-        self.assertEqual(len(list(files)), 0)
+        assert len(list(files)) == 0
-        self.assertEqual(len(list(chunks)), 0)
+        assert len(list(chunks)) == 0
 
         # Test case where we overwrite the file
         testfile = TestFile()
         testfile.the_file.put(text, content_type=content_type, filename="hello")
         testfile.save()
 
-        text = six.b('Bonjour, World!')
+        text = "Bonjour, World!".encode("latin-1")
         testfile.the_file.replace(text, content_type=content_type, filename="hello")
         testfile.save()
 
         files = db.fs.files.find()
         chunks = db.fs.chunks.find()
-        self.assertEqual(len(list(files)), 1)
+        assert len(list(files)) == 1
-        self.assertEqual(len(list(chunks)), 1)
+        assert len(list(chunks)) == 1
 
         testfile.delete()
 
         files = db.fs.files.find()
         chunks = db.fs.chunks.find()
-        self.assertEqual(len(list(files)), 0)
+        assert len(list(files)) == 0
-        self.assertEqual(len(list(chunks)), 0)
+        assert len(list(chunks)) == 0
 
+    @require_pil
     def test_image_field(self):
-        if not HAS_PIL:
-            raise SkipTest('PIL not installed')
-
         class TestImage(Document):
             image = ImageField()
 
         TestImage.drop_collection()
 
         with tempfile.TemporaryFile() as f:
-            f.write(six.b("Hello World!"))
+            f.write("Hello World!".encode("latin-1"))
             f.flush()
 
             t = TestImage()
@@ -386,7 +396,7 @@ class FileTest(MongoDBTestCase):
                 t.image.put(f)
                 self.fail("Should have raised an invalidation error")
             except ValidationError as e:
-                self.assertEqual("%s" % e, "Invalid image: cannot identify image file %s" % f)
+                assert "%s" % e == "Invalid image: cannot identify image file %s" % f
 
         t = TestImage()
         t.image.put(get_file(TEST_IMAGE_PATH))
@@ -394,34 +404,31 @@ class FileTest(MongoDBTestCase):
 
         t = TestImage.objects.first()
 
-        self.assertEqual(t.image.format, 'PNG')
+        assert t.image.format == "PNG"
 
         w, h = t.image.size
-        self.assertEqual(w, 371)
+        assert w == 371
-        self.assertEqual(h, 76)
+        assert h == 76
 
         t.image.delete()
 
+    @require_pil
     def test_image_field_reassigning(self):
-        if not HAS_PIL:
-            raise SkipTest('PIL not installed')
-
         class TestFile(Document):
             the_file = ImageField()
+
         TestFile.drop_collection()
 
         test_file = TestFile(the_file=get_file(TEST_IMAGE_PATH)).save()
-        self.assertEqual(test_file.the_file.size, (371, 76))
+        assert test_file.the_file.size == (371, 76)
 
         test_file = TestFile.objects.first()
         test_file.the_file = get_file(TEST_IMAGE2_PATH)
         test_file.save()
-        self.assertEqual(test_file.the_file.size, (45, 101))
+        assert test_file.the_file.size == (45, 101)
 
+    @require_pil
     def test_image_field_resize(self):
-        if not HAS_PIL:
-            raise SkipTest('PIL not installed')
-
         class TestImage(Document):
             image = ImageField(size=(185, 37))
 
@@ -433,18 +440,16 @@ class FileTest(MongoDBTestCase):
 
         t = TestImage.objects.first()
 
-        self.assertEqual(t.image.format, 'PNG')
+        assert t.image.format == "PNG"
         w, h = t.image.size
 
-        self.assertEqual(w, 185)
+        assert w == 185
-        self.assertEqual(h, 37)
+        assert h == 37
 
         t.image.delete()
 
+    @require_pil
     def test_image_field_resize_force(self):
-        if not HAS_PIL:
-            raise SkipTest('PIL not installed')
-
         class TestImage(Document):
             image = ImageField(size=(185, 37, True))
 
@@ -456,18 +461,16 @@ class FileTest(MongoDBTestCase):
 
         t = TestImage.objects.first()
 
-        self.assertEqual(t.image.format, 'PNG')
+        assert t.image.format == "PNG"
         w, h = t.image.size
 
-        self.assertEqual(w, 185)
+        assert w == 185
-        self.assertEqual(h, 37)
+        assert h == 37
 
         t.image.delete()
 
+    @require_pil
     def test_image_field_thumbnail(self):
-        if not HAS_PIL:
-            raise SkipTest('PIL not installed')
-
         class TestImage(Document):
             image = ImageField(thumbnail_size=(92, 18))
 
@@ -479,19 +482,18 @@ class FileTest(MongoDBTestCase):
 
         t = TestImage.objects.first()
 
-        self.assertEqual(t.image.thumbnail.format, 'PNG')
+        assert t.image.thumbnail.format == "PNG"
-        self.assertEqual(t.image.thumbnail.width, 92)
+        assert t.image.thumbnail.width == 92
-        self.assertEqual(t.image.thumbnail.height, 18)
+        assert t.image.thumbnail.height == 18
 
         t.image.delete()
 
     def test_file_multidb(self):
-        register_connection('test_files', 'test_files')
+        register_connection("test_files", "test_files")
 
         class TestFile(Document):
             name = StringField()
-            the_file = FileField(db_alias="test_files",
+            the_file = FileField(db_alias="test_files", collection_name="macumba")
-                                 collection_name="macumba")
 
         TestFile.drop_collection()
 
@@ -502,23 +504,21 @@ class FileTest(MongoDBTestCase):
         # First instance
         test_file = TestFile()
         test_file.name = "Hello, World!"
-        test_file.the_file.put(six.b('Hello, World!'),
+        test_file.the_file.put("Hello, World!".encode("latin-1"), name="hello.txt")
-                          name="hello.txt")
         test_file.save()
 
         data = get_db("test_files").macumba.files.find_one()
-        self.assertEqual(data.get('name'), 'hello.txt')
+        assert data.get("name") == "hello.txt"
 
         test_file = TestFile.objects.first()
-        self.assertEqual(test_file.the_file.read(), six.b('Hello, World!'))
+        assert test_file.the_file.read() == "Hello, World!".encode("latin-1")
 
         test_file = TestFile.objects.first()
-        test_file.the_file = six.b('HELLO, WORLD!')
+        test_file.the_file = "Hello, World!".encode("latin-1")
         test_file.save()
 
         test_file = TestFile.objects.first()
-        self.assertEqual(test_file.the_file.read(),
+        assert test_file.the_file.read() == "Hello, World!".encode("latin-1")
-                         six.b('HELLO, WORLD!'))
 
     def test_copyable(self):
         class PutFile(Document):
@@ -526,8 +526,8 @@ class FileTest(MongoDBTestCase):
 
         PutFile.drop_collection()
 
-        text = six.b('Hello, World!')
+        text = "Hello, World!".encode("latin-1")
-        content_type = 'text/plain'
+        content_type = "text/plain"
 
         putfile = PutFile()
         putfile.the_file.put(text, content_type=content_type)
@@ -536,14 +536,11 @@ class FileTest(MongoDBTestCase):
         class TestFile(Document):
             name = StringField()
 
-        self.assertEqual(putfile, copy.copy(putfile))
+        assert putfile == copy.copy(putfile)
-        self.assertEqual(putfile, copy.deepcopy(putfile))
+        assert putfile == copy.deepcopy(putfile)
 
+    @require_pil
     def test_get_image_by_grid_id(self):
-
-        if not HAS_PIL:
-            raise SkipTest('PIL not installed')
-
         class TestImage(Document):
 
             image1 = ImageField()
@@ -559,8 +556,7 @@ class FileTest(MongoDBTestCase):
         test = TestImage.objects.first()
         grid_id = test.image1.grid_id
 
-        self.assertEqual(1, TestImage.objects(Q(image1=grid_id)
+        assert 1 == TestImage.objects(Q(image1=grid_id) or Q(image2=grid_id)).count()
-                                              or Q(image2=grid_id)).count())
 
     def test_complex_field_filefield(self):
         """Ensure you can add meta data to file"""
@@ -571,21 +567,21 @@ class FileTest(MongoDBTestCase):
             photos = ListField(FileField())
 
         Animal.drop_collection()
-        marmot = Animal(genus='Marmota', family='Sciuridae')
+        marmot = Animal(genus="Marmota", family="Sciuridae")
 
-        with open(TEST_IMAGE_PATH, 'rb') as marmot_photo:   # Retrieve a photo from disk
+        with open(TEST_IMAGE_PATH, "rb") as marmot_photo:  # Retrieve a photo from disk
-            photos_field = marmot._fields['photos'].field
+            photos_field = marmot._fields["photos"].field
-            new_proxy = photos_field.get_proxy_obj('photos', marmot)
+            new_proxy = photos_field.get_proxy_obj("photos", marmot)
-            new_proxy.put(marmot_photo, content_type='image/jpeg', foo='bar')
+            new_proxy.put(marmot_photo, content_type="image/jpeg", foo="bar")
 
         marmot.photos.append(new_proxy)
         marmot.save()
 
         marmot = Animal.objects.get()
-        self.assertEqual(marmot.photos[0].content_type, 'image/jpeg')
+        assert marmot.photos[0].content_type == "image/jpeg"
-        self.assertEqual(marmot.photos[0].foo, 'bar')
+        assert marmot.photos[0].foo == "bar"
-        self.assertEqual(marmot.photos[0].get().length, 8313)
+        assert marmot.photos[0].get().length == 8313
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/fields/test_float_field.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-import six
+import pytest
 
 from mongoengine import *
 
@@ -7,7 +7,6 @@ from tests.utils import MongoDBTestCase
 
 
 class TestFloatField(MongoDBTestCase):
-
     def test_float_ne_operator(self):
         class TestDocument(Document):
             float_fld = FloatField()
@@ -17,12 +16,13 @@ class TestFloatField(MongoDBTestCase):
         TestDocument(float_fld=None).save()
         TestDocument(float_fld=1).save()
 
-        self.assertEqual(1, TestDocument.objects(float_fld__ne=None).count())
+        assert 1 == TestDocument.objects(float_fld__ne=None).count()
-        self.assertEqual(1, TestDocument.objects(float_fld__ne=1).count())
+        assert 1 == TestDocument.objects(float_fld__ne=1).count()
 
     def test_validation(self):
         """Ensure that invalid values cannot be assigned to float fields.
         """
+
         class Person(Document):
             height = FloatField(min_value=0.1, max_value=3.5)
 
@@ -33,26 +33,30 @@ class TestFloatField(MongoDBTestCase):
         person.height = 1.89
         person.validate()
 
-        person.height = '2.0'
+        person.height = "2.0"
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
 
         person.height = 0.01
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
 
         person.height = 4.0
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
 
-        person_2 = Person(height='something invalid')
+        person_2 = Person(height="something invalid")
-        self.assertRaises(ValidationError, person_2.validate)
+        with pytest.raises(ValidationError):
+            person_2.validate()
 
         big_person = BigPerson()
 
-        for value, value_type in enumerate(six.integer_types):
+        big_person.height = int(0)
-            big_person.height = value_type(value)
+        big_person.validate()
-            big_person.validate()
 
         big_person.height = 2 ** 500
         big_person.validate()
 
         big_person.height = 2 ** 100000  # Too big for a float value
-        self.assertRaises(ValidationError, big_person.validate)
+        with pytest.raises(ValidationError):
+            big_person.validate()

tests/fields/test_geo_fields.py

@@ -2,30 +2,23 @@
 import unittest
 
 from mongoengine import *
-from mongoengine.connection import get_db
+from tests.utils import MongoDBTestCase
-
-__all__ = ("GeoFieldTest", )
 
 
-class GeoFieldTest(unittest.TestCase):
+class TestGeoField(MongoDBTestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-        self.db = get_db()
-
     def _test_for_expected_error(self, Cls, loc, expected):
         try:
             Cls(loc=loc).validate()
-            self.fail('Should not validate the location {0}'.format(loc))
+            self.fail("Should not validate the location {0}".format(loc))
         except ValidationError as e:
-            self.assertEqual(expected, e.to_dict()['loc'])
+            assert expected == e.to_dict()["loc"]
 
     def test_geopoint_validation(self):
         class Location(Document):
             loc = GeoPointField()
 
         invalid_coords = [{"x": 1, "y": 2}, 5, "a"]
-        expected = 'GeoPointField can only accept tuples or lists of (x, y)'
+        expected = "GeoPointField can only accept tuples or lists of (x, y)"
 
         for coord in invalid_coords:
             self._test_for_expected_error(Location, coord, expected)
@@ -40,7 +33,7 @@ class GeoFieldTest(unittest.TestCase):
             expected = "Both values (%s) in point must be float or int" % repr(coord)
             self._test_for_expected_error(Location, coord, expected)
 
-        invalid_coords = [21, 4, 'a']
+        invalid_coords = [21, 4, "a"]
         for coord in invalid_coords:
             expected = "GeoPointField can only accept tuples or lists of (x, y)"
             self._test_for_expected_error(Location, coord, expected)
@@ -50,7 +43,9 @@ class GeoFieldTest(unittest.TestCase):
             loc = PointField()
 
         invalid_coords = {"x": 1, "y": 2}
-        expected = 'PointField can only accept a valid GeoJson dictionary or lists of (x, y)'
+        expected = (
+            "PointField can only accept a valid GeoJson dictionary or lists of (x, y)"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MadeUp", "coordinates": []}
@@ -77,19 +72,16 @@ class GeoFieldTest(unittest.TestCase):
             self._test_for_expected_error(Location, coord, expected)
 
         Location(loc=[1, 2]).validate()
-        Location(loc={
+        Location(
-            "type": "Point",
+            loc={"type": "Point", "coordinates": [81.4471435546875, 23.61432859499169]}
-            "coordinates": [
+        ).validate()
-              81.4471435546875,
-              23.61432859499169
-            ]}).validate()
 
     def test_linestring_validation(self):
         class Location(Document):
             loc = LineStringField()
 
         invalid_coords = {"x": 1, "y": 2}
-        expected = 'LineStringField can only accept a valid GeoJson dictionary or lists of (x, y)'
+        expected = "LineStringField can only accept a valid GeoJson dictionary or lists of (x, y)"
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MadeUp", "coordinates": [[]]}
@@ -97,7 +89,9 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "LineString", "coordinates": [[1, 2, 3]]}
-        expected = "Invalid LineString:\nValue ([1, 2, 3]) must be a two-dimensional point"
+        expected = (
+            "Invalid LineString:\nValue ([1, 2, 3]) must be a two-dimensional point"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [5, "a"]
@@ -105,16 +99,25 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[1]]
-        expected = "Invalid LineString:\nValue (%s) must be a two-dimensional point" % repr(invalid_coords[0])
+        expected = (
+            "Invalid LineString:\nValue (%s) must be a two-dimensional point"
+            % repr(invalid_coords[0])
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[1, 2, 3]]
-        expected = "Invalid LineString:\nValue (%s) must be a two-dimensional point" % repr(invalid_coords[0])
+        expected = (
+            "Invalid LineString:\nValue (%s) must be a two-dimensional point"
+            % repr(invalid_coords[0])
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[{}, {}]], [("a", "b")]]
         for coord in invalid_coords:
-            expected = "Invalid LineString:\nBoth values (%s) in point must be float or int" % repr(coord[0])
+            expected = (
+                "Invalid LineString:\nBoth values (%s) in point must be float or int"
+                % repr(coord[0])
+            )
             self._test_for_expected_error(Location, coord, expected)
 
         Location(loc=[[1, 2], [3, 4], [5, 6], [1, 2]]).validate()
@@ -124,7 +127,9 @@ class GeoFieldTest(unittest.TestCase):
             loc = PolygonField()
 
         invalid_coords = {"x": 1, "y": 2}
-        expected = 'PolygonField can only accept a valid GeoJson dictionary or lists of (x, y)'
+        expected = (
+            "PolygonField can only accept a valid GeoJson dictionary or lists of (x, y)"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MadeUp", "coordinates": [[]]}
@@ -136,7 +141,9 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[5, "a"]]]
-        expected = "Invalid Polygon:\nBoth values ([5, 'a']) in point must be float or int"
+        expected = (
+            "Invalid Polygon:\nBoth values ([5, 'a']) in point must be float or int"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[]]]
@@ -162,7 +169,7 @@ class GeoFieldTest(unittest.TestCase):
             loc = MultiPointField()
 
         invalid_coords = {"x": 1, "y": 2}
-        expected = 'MultiPointField can only accept a valid GeoJson dictionary or lists of (x, y)'
+        expected = "MultiPointField can only accept a valid GeoJson dictionary or lists of (x, y)"
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MadeUp", "coordinates": [[]]}
@@ -188,19 +195,19 @@ class GeoFieldTest(unittest.TestCase):
             self._test_for_expected_error(Location, coord, expected)
 
         Location(loc=[[1, 2]]).validate()
-        Location(loc={
+        Location(
-            "type": "MultiPoint",
+            loc={
-            "coordinates": [
+                "type": "MultiPoint",
-                [1, 2],
+                "coordinates": [[1, 2], [81.4471435546875, 23.61432859499169]],
-                [81.4471435546875, 23.61432859499169]
+            }
-            ]}).validate()
+        ).validate()
 
     def test_multilinestring_validation(self):
         class Location(Document):
             loc = MultiLineStringField()
 
         invalid_coords = {"x": 1, "y": 2}
-        expected = 'MultiLineStringField can only accept a valid GeoJson dictionary or lists of (x, y)'
+        expected = "MultiLineStringField can only accept a valid GeoJson dictionary or lists of (x, y)"
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MadeUp", "coordinates": [[]]}
@@ -216,16 +223,25 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[1]]]
-        expected = "Invalid MultiLineString:\nValue (%s) must be a two-dimensional point" % repr(invalid_coords[0][0])
+        expected = (
+            "Invalid MultiLineString:\nValue (%s) must be a two-dimensional point"
+            % repr(invalid_coords[0][0])
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[1, 2, 3]]]
-        expected = "Invalid MultiLineString:\nValue (%s) must be a two-dimensional point" % repr(invalid_coords[0][0])
+        expected = (
+            "Invalid MultiLineString:\nValue (%s) must be a two-dimensional point"
+            % repr(invalid_coords[0][0])
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[[{}, {}]]], [[("a", "b")]]]
         for coord in invalid_coords:
-            expected = "Invalid MultiLineString:\nBoth values (%s) in point must be float or int" % repr(coord[0][0])
+            expected = (
+                "Invalid MultiLineString:\nBoth values (%s) in point must be float or int"
+                % repr(coord[0][0])
+            )
             self._test_for_expected_error(Location, coord, expected)
 
         Location(loc=[[[1, 2], [3, 4], [5, 6], [1, 2]]]).validate()
@@ -235,7 +251,7 @@ class GeoFieldTest(unittest.TestCase):
             loc = MultiPolygonField()
 
         invalid_coords = {"x": 1, "y": 2}
-        expected = 'MultiPolygonField can only accept a valid GeoJson dictionary or lists of (x, y)'
+        expected = "MultiPolygonField can only accept a valid GeoJson dictionary or lists of (x, y)"
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MadeUp", "coordinates": [[]]}
@@ -243,7 +259,9 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = {"type": "MultiPolygon", "coordinates": [[[[1, 2, 3]]]]}
-        expected = "Invalid MultiPolygon:\nValue ([1, 2, 3]) must be a two-dimensional point"
+        expected = (
+            "Invalid MultiPolygon:\nValue ([1, 2, 3]) must be a two-dimensional point"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[[5, "a"]]]]
@@ -255,7 +273,9 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[[1, 2, 3]]]]
-        expected = "Invalid MultiPolygon:\nValue ([1, 2, 3]) must be a two-dimensional point"
+        expected = (
+            "Invalid MultiPolygon:\nValue ([1, 2, 3]) must be a two-dimensional point"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[[{}, {}]]], [[("a", "b")]]]
@@ -263,7 +283,9 @@ class GeoFieldTest(unittest.TestCase):
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         invalid_coords = [[[[1, 2], [3, 4]]]]
-        expected = "Invalid MultiPolygon:\nLineStrings must start and end at the same point"
+        expected = (
+            "Invalid MultiPolygon:\nLineStrings must start and end at the same point"
+        )
         self._test_for_expected_error(Location, invalid_coords, expected)
 
         Location(loc=[[[[1, 2], [3, 4], [5, 6], [1, 2]]]]).validate()
@@ -271,17 +293,19 @@ class GeoFieldTest(unittest.TestCase):
     def test_indexes_geopoint(self):
         """Ensure that indexes are created automatically for GeoPointFields.
         """
+
         class Event(Document):
             title = StringField()
             location = GeoPointField()
 
         geo_indicies = Event._geo_indices()
-        self.assertEqual(geo_indicies, [{'fields': [('location', '2d')]}])
+        assert geo_indicies == [{"fields": [("location", "2d")]}]
 
     def test_geopoint_embedded_indexes(self):
         """Ensure that indexes are created automatically for GeoPointFields on
         embedded documents.
         """
+
         class Venue(EmbeddedDocument):
             location = GeoPointField()
             name = StringField()
@@ -291,11 +315,12 @@ class GeoFieldTest(unittest.TestCase):
             venue = EmbeddedDocumentField(Venue)
 
         geo_indicies = Event._geo_indices()
-        self.assertEqual(geo_indicies, [{'fields': [('venue.location', '2d')]}])
+        assert geo_indicies == [{"fields": [("venue.location", "2d")]}]
 
     def test_indexes_2dsphere(self):
         """Ensure that indexes are created automatically for GeoPointFields.
         """
+
         class Event(Document):
             title = StringField()
             point = PointField()
@@ -303,13 +328,14 @@ class GeoFieldTest(unittest.TestCase):
             polygon = PolygonField()
 
         geo_indicies = Event._geo_indices()
-        self.assertIn({'fields': [('line', '2dsphere')]}, geo_indicies)
+        assert {"fields": [("line", "2dsphere")]} in geo_indicies
-        self.assertIn({'fields': [('polygon', '2dsphere')]}, geo_indicies)
+        assert {"fields": [("polygon", "2dsphere")]} in geo_indicies
-        self.assertIn({'fields': [('point', '2dsphere')]}, geo_indicies)
+        assert {"fields": [("point", "2dsphere")]} in geo_indicies
 
     def test_indexes_2dsphere_embedded(self):
         """Ensure that indexes are created automatically for GeoPointFields.
         """
+
         class Venue(EmbeddedDocument):
             name = StringField()
             point = PointField()
@@ -321,12 +347,11 @@ class GeoFieldTest(unittest.TestCase):
             venue = EmbeddedDocumentField(Venue)
 
         geo_indicies = Event._geo_indices()
-        self.assertIn({'fields': [('venue.line', '2dsphere')]}, geo_indicies)
+        assert {"fields": [("venue.line", "2dsphere")]} in geo_indicies
-        self.assertIn({'fields': [('venue.polygon', '2dsphere')]}, geo_indicies)
+        assert {"fields": [("venue.polygon", "2dsphere")]} in geo_indicies
-        self.assertIn({'fields': [('venue.point', '2dsphere')]}, geo_indicies)
+        assert {"fields": [("venue.point", "2dsphere")]} in geo_indicies
 
     def test_geo_indexes_recursion(self):
-
         class Location(Document):
             name = StringField()
             location = GeoPointField()
@@ -338,14 +363,14 @@ class GeoFieldTest(unittest.TestCase):
         Location.drop_collection()
         Parent.drop_collection()
 
-        Parent(name='Berlin').save()
+        Parent(name="Berlin").save()
         info = Parent._get_collection().index_information()
-        self.assertNotIn('location_2d', info)
+        assert "location_2d" not in info
         info = Location._get_collection().index_information()
-        self.assertIn('location_2d', info)
+        assert "location_2d" in info
 
-        self.assertEqual(len(Parent._geo_indices()), 0)
+        assert len(Parent._geo_indices()) == 0
-        self.assertEqual(len(Location._geo_indices()), 1)
+        assert len(Location._geo_indices()) == 1
 
     def test_geo_indexes_auto_index(self):
 
@@ -354,18 +379,18 @@ class GeoFieldTest(unittest.TestCase):
             location = PointField(auto_index=False)
             datetime = DateTimeField()
 
-            meta = {
+            meta = {"indexes": [[("location", "2dsphere"), ("datetime", 1)]]}
-                'indexes': [[("location", "2dsphere"), ("datetime", 1)]]
-            }
 
-        self.assertEqual([], Log._geo_indices())
+        assert Log._geo_indices() == []
 
         Log.drop_collection()
         Log.ensure_indexes()
 
         info = Log._get_collection().index_information()
-        self.assertEqual(info["location_2dsphere_datetime_1"]["key"],
+        assert info["location_2dsphere_datetime_1"]["key"] == [
-                         [('location', '2dsphere'), ('datetime', 1)])
+            ("location", "2dsphere"),
+            ("datetime", 1),
+        ]
 
         # Test listing explicitly
         class Log(Document):
@@ -373,20 +398,20 @@ class GeoFieldTest(unittest.TestCase):
             datetime = DateTimeField()
 
             meta = {
-                'indexes': [
+                "indexes": [{"fields": [("location", "2dsphere"), ("datetime", 1)]}]
-                    {'fields': [("location", "2dsphere"), ("datetime", 1)]}
-                ]
             }
 
-        self.assertEqual([], Log._geo_indices())
+        assert Log._geo_indices() == []
 
         Log.drop_collection()
         Log.ensure_indexes()
 
         info = Log._get_collection().index_information()
-        self.assertEqual(info["location_2dsphere_datetime_1"]["key"],
+        assert info["location_2dsphere_datetime_1"]["key"] == [
-                         [('location', '2dsphere'), ('datetime', 1)])
+            ("location", "2dsphere"),
+            ("datetime", 1),
+        ]
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/fields/test_int_field.py

@@ -1,14 +1,16 @@
 # -*- coding: utf-8 -*-
+import pytest
+
 from mongoengine import *
 
 from tests.utils import MongoDBTestCase
 
 
 class TestIntField(MongoDBTestCase):
-
     def test_int_validation(self):
         """Ensure that invalid values cannot be assigned to int fields.
         """
+
         class Person(Document):
             age = IntField(min_value=0, max_value=110)
 
@@ -23,11 +25,14 @@ class TestIntField(MongoDBTestCase):
         person.validate()
 
         person.age = -1
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
+            person.validate()
         person.age = 120
-        self.assertRaises(ValidationError, person.validate)
+        with pytest.raises(ValidationError):
-        person.age = 'ten'
+            person.validate()
-        self.assertRaises(ValidationError, person.validate)
+        person.age = "ten"
+        with pytest.raises(ValidationError):
+            person.validate()
 
     def test_ne_operator(self):
         class TestDocument(Document):
@@ -38,5 +43,5 @@ class TestIntField(MongoDBTestCase):
         TestDocument(int_fld=None).save()
         TestDocument(int_fld=1).save()
 
-        self.assertEqual(1, TestDocument.objects(int_fld__ne=None).count())
+        assert 1 == TestDocument.objects(int_fld__ne=None).count()
-        self.assertEqual(1, TestDocument.objects(int_fld__ne=1).count())
+        assert 1 == TestDocument.objects(int_fld__ne=1).count()

tests/fields/test_lazy_reference_field.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 from bson import DBRef, ObjectId
+import pytest
 
 from mongoengine import *
 from mongoengine.base import LazyReference
@@ -11,7 +12,8 @@ class TestLazyReferenceField(MongoDBTestCase):
     def test_lazy_reference_config(self):
         # Make sure ReferenceField only accepts a document class or a string
         # with a document class name.
-        self.assertRaises(ValidationError, LazyReferenceField, EmbeddedDocument)
+        with pytest.raises(ValidationError):
+            LazyReferenceField(EmbeddedDocument)
 
     def test___repr__(self):
         class Animal(Document):
@@ -25,7 +27,7 @@ class TestLazyReferenceField(MongoDBTestCase):
 
         animal = Animal()
         oc = Ocurrence(animal=animal)
-        self.assertIn('LazyReference', repr(oc.animal))
+        assert "LazyReference" in repr(oc.animal)
 
     def test___getattr___unknown_attr_raises_attribute_error(self):
         class Animal(Document):
@@ -39,7 +41,7 @@ class TestLazyReferenceField(MongoDBTestCase):
 
         animal = Animal().save()
         oc = Ocurrence(animal=animal)
-        with self.assertRaises(AttributeError):
+        with pytest.raises(AttributeError):
             oc.animal.not_exist
 
     def test_lazy_reference_simple(self):
@@ -57,19 +59,19 @@ class TestLazyReferenceField(MongoDBTestCase):
         animal = Animal(name="Leopard", tag="heavy").save()
         Ocurrence(person="test", animal=animal).save()
         p = Ocurrence.objects.get()
-        self.assertIsInstance(p.animal, LazyReference)
+        assert isinstance(p.animal, LazyReference)
         fetched_animal = p.animal.fetch()
-        self.assertEqual(fetched_animal, animal)
+        assert fetched_animal == animal
         # `fetch` keep cache on referenced document by default...
         animal.tag = "not so heavy"
         animal.save()
         double_fetch = p.animal.fetch()
-        self.assertIs(fetched_animal, double_fetch)
+        assert fetched_animal is double_fetch
-        self.assertEqual(double_fetch.tag, "heavy")
+        assert double_fetch.tag == "heavy"
         # ...unless specified otherwise
         fetch_force = p.animal.fetch(force=True)
-        self.assertIsNot(fetch_force, fetched_animal)
+        assert fetch_force is not fetched_animal
-        self.assertEqual(fetch_force.tag, "not so heavy")
+        assert fetch_force.tag == "not so heavy"
 
     def test_lazy_reference_fetch_invalid_ref(self):
         class Animal(Document):
@@ -87,13 +89,13 @@ class TestLazyReferenceField(MongoDBTestCase):
         Ocurrence(person="test", animal=animal).save()
         animal.delete()
         p = Ocurrence.objects.get()
-        self.assertIsInstance(p.animal, LazyReference)
+        assert isinstance(p.animal, LazyReference)
-        with self.assertRaises(DoesNotExist):
+        with pytest.raises(DoesNotExist):
             p.animal.fetch()
 
     def test_lazy_reference_set(self):
         class Animal(Document):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
             name = StringField()
             tag = StringField()
@@ -109,21 +111,20 @@ class TestLazyReferenceField(MongoDBTestCase):
             nick = StringField()
 
         animal = Animal(name="Leopard", tag="heavy").save()
-        sub_animal = SubAnimal(nick='doggo', name='dog').save()
+        sub_animal = SubAnimal(nick="doggo", name="dog").save()
         for ref in (
-                animal,
+            animal,
-                animal.pk,
+            animal.pk,
-                DBRef(animal._get_collection_name(), animal.pk),
+            DBRef(animal._get_collection_name(), animal.pk),
-                LazyReference(Animal, animal.pk),
+            LazyReference(Animal, animal.pk),
-
+            sub_animal,
-                sub_animal,
+            sub_animal.pk,
-                sub_animal.pk,
+            DBRef(sub_animal._get_collection_name(), sub_animal.pk),
-                DBRef(sub_animal._get_collection_name(), sub_animal.pk),
+            LazyReference(SubAnimal, sub_animal.pk),
-                LazyReference(SubAnimal, sub_animal.pk),
+        ):
-                ):
             p = Ocurrence(person="test", animal=ref).save()
             p.reload()
-            self.assertIsInstance(p.animal, LazyReference)
+            assert isinstance(p.animal, LazyReference)
             p.animal.fetch()
 
     def test_lazy_reference_bad_set(self):
@@ -144,19 +145,20 @@ class TestLazyReferenceField(MongoDBTestCase):
         animal = Animal(name="Leopard", tag="heavy").save()
         baddoc = BadDoc().save()
         for bad in (
-                42,
+            42,
-                'foo',
+            "foo",
-                baddoc,
+            baddoc,
-                DBRef(baddoc._get_collection_name(), animal.pk),
+            DBRef(baddoc._get_collection_name(), animal.pk),
-                LazyReference(BadDoc, animal.pk)
+            LazyReference(BadDoc, animal.pk),
-                ):
+        ):
-            with self.assertRaises(ValidationError):
+            with pytest.raises(ValidationError):
-                p = Ocurrence(person="test", animal=bad).save()
+                Ocurrence(person="test", animal=bad).save()
 
     def test_lazy_reference_query_conversion(self):
         """Ensure that LazyReferenceFields can be queried using objects and values
         of the type of the primary key of the referenced object.
         """
+
         class Member(Document):
             user_num = IntField(primary_key=True)
 
@@ -172,26 +174,27 @@ class TestLazyReferenceField(MongoDBTestCase):
         m2 = Member(user_num=2)
         m2.save()
 
-        post1 = BlogPost(title='post 1', author=m1)
+        post1 = BlogPost(title="post 1", author=m1)
         post1.save()
 
-        post2 = BlogPost(title='post 2', author=m2)
+        post2 = BlogPost(title="post 2", author=m2)
         post2.save()
 
         post = BlogPost.objects(author=m1).first()
-        self.assertEqual(post.id, post1.id)
+        assert post.id == post1.id
 
         post = BlogPost.objects(author=m2).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
         # Same thing by passing a LazyReference instance
         post = BlogPost.objects(author=LazyReference(Member, m2.pk)).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
     def test_lazy_reference_query_conversion_dbref(self):
         """Ensure that LazyReferenceFields can be queried using objects and values
         of the type of the primary key of the referenced object.
         """
+
         class Member(Document):
             user_num = IntField(primary_key=True)
 
@@ -207,21 +210,21 @@ class TestLazyReferenceField(MongoDBTestCase):
         m2 = Member(user_num=2)
         m2.save()
 
-        post1 = BlogPost(title='post 1', author=m1)
+        post1 = BlogPost(title="post 1", author=m1)
         post1.save()
 
-        post2 = BlogPost(title='post 2', author=m2)
+        post2 = BlogPost(title="post 2", author=m2)
         post2.save()
 
         post = BlogPost.objects(author=m1).first()
-        self.assertEqual(post.id, post1.id)
+        assert post.id == post1.id
 
         post = BlogPost.objects(author=m2).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
         # Same thing by passing a LazyReference instance
         post = BlogPost.objects(author=LazyReference(Member, m2.pk)).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
     def test_lazy_reference_passthrough(self):
         class Animal(Document):
@@ -238,21 +241,21 @@ class TestLazyReferenceField(MongoDBTestCase):
         animal = Animal(name="Leopard", tag="heavy").save()
         Ocurrence(animal=animal, animal_passthrough=animal).save()
         p = Ocurrence.objects.get()
-        self.assertIsInstance(p.animal, LazyReference)
+        assert isinstance(p.animal, LazyReference)
-        with self.assertRaises(KeyError):
+        with pytest.raises(KeyError):
-            p.animal['name']
+            p.animal["name"]
-        with self.assertRaises(AttributeError):
+        with pytest.raises(AttributeError):
             p.animal.name
-        self.assertEqual(p.animal.pk, animal.pk)
+        assert p.animal.pk == animal.pk
 
-        self.assertEqual(p.animal_passthrough.name, "Leopard")
+        assert p.animal_passthrough.name == "Leopard"
-        self.assertEqual(p.animal_passthrough['name'], "Leopard")
+        assert p.animal_passthrough["name"] == "Leopard"
 
         # Should not be able to access referenced document's methods
-        with self.assertRaises(AttributeError):
+        with pytest.raises(AttributeError):
             p.animal.save
-        with self.assertRaises(KeyError):
+        with pytest.raises(KeyError):
-            p.animal['save']
+            p.animal["save"]
 
     def test_lazy_reference_not_set(self):
         class Animal(Document):
@@ -266,9 +269,9 @@ class TestLazyReferenceField(MongoDBTestCase):
         Animal.drop_collection()
         Ocurrence.drop_collection()
 
-        Ocurrence(person='foo').save()
+        Ocurrence(person="foo").save()
         p = Ocurrence.objects.get()
-        self.assertIs(p.animal, None)
+        assert p.animal is None
 
     def test_lazy_reference_equality(self):
         class Animal(Document):
@@ -279,12 +282,12 @@ class TestLazyReferenceField(MongoDBTestCase):
 
         animal = Animal(name="Leopard", tag="heavy").save()
         animalref = LazyReference(Animal, animal.pk)
-        self.assertEqual(animal, animalref)
+        assert animal == animalref
-        self.assertEqual(animalref, animal)
+        assert animalref == animal
 
         other_animalref = LazyReference(Animal, ObjectId("54495ad94c934721ede76f90"))
-        self.assertNotEqual(animal, other_animalref)
+        assert animal != other_animalref
-        self.assertNotEqual(other_animalref, animal)
+        assert other_animalref != animal
 
     def test_lazy_reference_embedded(self):
         class Animal(Document):
@@ -303,21 +306,21 @@ class TestLazyReferenceField(MongoDBTestCase):
         Animal.drop_collection()
         Ocurrence.drop_collection()
 
-        animal1 = Animal('doggo').save()
+        animal1 = Animal(name="doggo").save()
-        animal2 = Animal('cheeta').save()
+        animal2 = Animal(name="cheeta").save()
 
         def check_fields_type(occ):
-            self.assertIsInstance(occ.direct, LazyReference)
+            assert isinstance(occ.direct, LazyReference)
             for elem in occ.in_list:
-                self.assertIsInstance(elem, LazyReference)
+                assert isinstance(elem, LazyReference)
-            self.assertIsInstance(occ.in_embedded.direct, LazyReference)
+            assert isinstance(occ.in_embedded.direct, LazyReference)
             for elem in occ.in_embedded.in_list:
-                self.assertIsInstance(elem, LazyReference)
+                assert isinstance(elem, LazyReference)
 
         occ = Ocurrence(
             in_list=[animal1, animal2],
-            in_embedded={'in_list': [animal1, animal2], 'direct': animal1},
+            in_embedded={"in_list": [animal1, animal2], "direct": animal1},
-            direct=animal1
+            direct=animal1,
         ).save()
         check_fields_type(occ)
         occ.reload()
@@ -345,19 +348,19 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
         animal = Animal(name="Leopard", tag="heavy").save()
         Ocurrence(person="test", animal=animal).save()
         p = Ocurrence.objects.get()
-        self.assertIsInstance(p.animal, LazyReference)
+        assert isinstance(p.animal, LazyReference)
         fetched_animal = p.animal.fetch()
-        self.assertEqual(fetched_animal, animal)
+        assert fetched_animal == animal
         # `fetch` keep cache on referenced document by default...
         animal.tag = "not so heavy"
         animal.save()
         double_fetch = p.animal.fetch()
-        self.assertIs(fetched_animal, double_fetch)
+        assert fetched_animal is double_fetch
-        self.assertEqual(double_fetch.tag, "heavy")
+        assert double_fetch.tag == "heavy"
         # ...unless specified otherwise
         fetch_force = p.animal.fetch(force=True)
-        self.assertIsNot(fetch_force, fetched_animal)
+        assert fetch_force is not fetched_animal
-        self.assertEqual(fetch_force.tag, "not so heavy")
+        assert fetch_force.tag == "not so heavy"
 
     def test_generic_lazy_reference_choices(self):
         class Animal(Document):
@@ -383,14 +386,14 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
         mineral = Mineral(name="Granite").save()
 
         occ_animal = Ocurrence(living_thing=animal, thing=animal).save()
-        occ_vegetal = Ocurrence(living_thing=vegetal, thing=vegetal).save()
+        _ = Ocurrence(living_thing=vegetal, thing=vegetal).save()
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
             Ocurrence(living_thing=mineral).save()
 
         occ = Ocurrence.objects.get(living_thing=animal)
-        self.assertEqual(occ, occ_animal)
+        assert occ == occ_animal
-        self.assertIsInstance(occ.thing, LazyReference)
+        assert isinstance(occ.thing, LazyReference)
-        self.assertIsInstance(occ.living_thing, LazyReference)
+        assert isinstance(occ.living_thing, LazyReference)
 
         occ.thing = vegetal
         occ.living_thing = vegetal
@@ -398,12 +401,12 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
 
         occ.thing = mineral
         occ.living_thing = mineral
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
             occ.save()
 
     def test_generic_lazy_reference_set(self):
         class Animal(Document):
-            meta = {'allow_inheritance': True}
+            meta = {"allow_inheritance": True}
 
             name = StringField()
             tag = StringField()
@@ -419,19 +422,21 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
             nick = StringField()
 
         animal = Animal(name="Leopard", tag="heavy").save()
-        sub_animal = SubAnimal(nick='doggo', name='dog').save()
+        sub_animal = SubAnimal(nick="doggo", name="dog").save()
         for ref in (
-                animal,
+            animal,
-                LazyReference(Animal, animal.pk),
+            LazyReference(Animal, animal.pk),
-                {'_cls': 'Animal', '_ref': DBRef(animal._get_collection_name(), animal.pk)},
+            {"_cls": "Animal", "_ref": DBRef(animal._get_collection_name(), animal.pk)},
-
+            sub_animal,
-                sub_animal,
+            LazyReference(SubAnimal, sub_animal.pk),
-                LazyReference(SubAnimal, sub_animal.pk),
+            {
-                {'_cls': 'SubAnimal', '_ref': DBRef(sub_animal._get_collection_name(), sub_animal.pk)},
+                "_cls": "SubAnimal",
-                ):
+                "_ref": DBRef(sub_animal._get_collection_name(), sub_animal.pk),
+            },
+        ):
             p = Ocurrence(person="test", animal=ref).save()
             p.reload()
-            self.assertIsInstance(p.animal, (LazyReference, Document))
+            assert isinstance(p.animal, (LazyReference, Document))
             p.animal.fetch()
 
     def test_generic_lazy_reference_bad_set(self):
@@ -441,7 +446,7 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
 
         class Ocurrence(Document):
             person = StringField()
-            animal = GenericLazyReferenceField(choices=['Animal'])
+            animal = GenericLazyReferenceField(choices=["Animal"])
 
         Animal.drop_collection()
         Ocurrence.drop_collection()
@@ -451,14 +456,9 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
 
         animal = Animal(name="Leopard", tag="heavy").save()
         baddoc = BadDoc().save()
-        for bad in (
+        for bad in (42, "foo", baddoc, LazyReference(BadDoc, animal.pk)):
-                42,
+            with pytest.raises(ValidationError):
-                'foo',
+                Ocurrence(person="test", animal=bad).save()
-                baddoc,
-                LazyReference(BadDoc, animal.pk)
-                ):
-            with self.assertRaises(ValidationError):
-                p = Ocurrence(person="test", animal=bad).save()
 
     def test_generic_lazy_reference_query_conversion(self):
         class Member(Document):
@@ -476,21 +476,21 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
         m2 = Member(user_num=2)
         m2.save()
 
-        post1 = BlogPost(title='post 1', author=m1)
+        post1 = BlogPost(title="post 1", author=m1)
         post1.save()
 
-        post2 = BlogPost(title='post 2', author=m2)
+        post2 = BlogPost(title="post 2", author=m2)
         post2.save()
 
         post = BlogPost.objects(author=m1).first()
-        self.assertEqual(post.id, post1.id)
+        assert post.id == post1.id
 
         post = BlogPost.objects(author=m2).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
         # Same thing by passing a LazyReference instance
         post = BlogPost.objects(author=LazyReference(Member, m2.pk)).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
     def test_generic_lazy_reference_not_set(self):
         class Animal(Document):
@@ -504,9 +504,9 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
         Animal.drop_collection()
         Ocurrence.drop_collection()
 
-        Ocurrence(person='foo').save()
+        Ocurrence(person="foo").save()
         p = Ocurrence.objects.get()
-        self.assertIs(p.animal, None)
+        assert p.animal is None
 
     def test_generic_lazy_reference_accepts_string_instead_of_class(self):
         class Animal(Document):
@@ -515,7 +515,7 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
 
         class Ocurrence(Document):
             person = StringField()
-            animal = GenericLazyReferenceField('Animal')
+            animal = GenericLazyReferenceField("Animal")
 
         Animal.drop_collection()
         Ocurrence.drop_collection()
@@ -523,7 +523,7 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
         animal = Animal().save()
         Ocurrence(animal=animal).save()
         p = Ocurrence.objects.get()
-        self.assertEqual(p.animal, animal)
+        assert p.animal == animal
 
     def test_generic_lazy_reference_embedded(self):
         class Animal(Document):
@@ -542,27 +542,33 @@ class TestGenericLazyReferenceField(MongoDBTestCase):
         Animal.drop_collection()
         Ocurrence.drop_collection()
 
-        animal1 = Animal('doggo').save()
+        animal1 = Animal(name="doggo").save()
-        animal2 = Animal('cheeta').save()
+        animal2 = Animal(name="cheeta").save()
 
         def check_fields_type(occ):
-            self.assertIsInstance(occ.direct, LazyReference)
+            assert isinstance(occ.direct, LazyReference)
             for elem in occ.in_list:
-                self.assertIsInstance(elem, LazyReference)
+                assert isinstance(elem, LazyReference)
-            self.assertIsInstance(occ.in_embedded.direct, LazyReference)
+            assert isinstance(occ.in_embedded.direct, LazyReference)
             for elem in occ.in_embedded.in_list:
-                self.assertIsInstance(elem, LazyReference)
+                assert isinstance(elem, LazyReference)
 
         occ = Ocurrence(
             in_list=[animal1, animal2],
-            in_embedded={'in_list': [animal1, animal2], 'direct': animal1},
+            in_embedded={"in_list": [animal1, animal2], "direct": animal1},
-            direct=animal1
+            direct=animal1,
         ).save()
         check_fields_type(occ)
         occ.reload()
         check_fields_type(occ)
-        animal1_ref = {'_cls': 'Animal', '_ref': DBRef(animal1._get_collection_name(), animal1.pk)}
+        animal1_ref = {
-        animal2_ref = {'_cls': 'Animal', '_ref': DBRef(animal2._get_collection_name(), animal2.pk)}
+            "_cls": "Animal",
+            "_ref": DBRef(animal1._get_collection_name(), animal1.pk),
+        }
+        animal2_ref = {
+            "_cls": "Animal",
+            "_ref": DBRef(animal2._get_collection_name(), animal2.pk),
+        }
         occ.direct = animal1_ref
         occ.in_list = [animal1_ref, animal2_ref]
         occ.in_embedded.direct = animal1_ref

tests/fields/test_long_field.py

@@ -1,10 +1,5 @@
-# -*- coding: utf-8 -*-
+from bson.int64 import Int64
-import six
+import pytest
-
-try:
-    from bson.int64 import Int64
-except ImportError:
-    Int64 = long
 
 from mongoengine import *
 from mongoengine.connection import get_db
@@ -13,23 +8,26 @@ from tests.utils import MongoDBTestCase
 
 
 class TestLongField(MongoDBTestCase):
-
     def test_long_field_is_considered_as_int64(self):
         """
         Tests that long fields are stored as long in mongo, even if long
         value is small enough to be an int.
         """
+
         class TestLongFieldConsideredAsInt64(Document):
             some_long = LongField()
 
         doc = TestLongFieldConsideredAsInt64(some_long=42).save()
         db = get_db()
-        self.assertIsInstance(db.test_long_field_considered_as_int64.find()[0]['some_long'], Int64)
+        assert isinstance(
-        self.assertIsInstance(doc.some_long, six.integer_types)
+            db.test_long_field_considered_as_int64.find()[0]["some_long"], Int64
+        )
+        assert isinstance(doc.some_long, int)
 
     def test_long_validation(self):
         """Ensure that invalid values cannot be assigned to long fields.
         """
+
         class TestDocument(Document):
             value = LongField(min_value=0, max_value=110)
 
@@ -38,11 +36,14 @@ class TestLongField(MongoDBTestCase):
         doc.validate()
 
         doc.value = -1
-        self.assertRaises(ValidationError, doc.validate)
+        with pytest.raises(ValidationError):
+            doc.validate()
         doc.value = 120
-        self.assertRaises(ValidationError, doc.validate)
+        with pytest.raises(ValidationError):
-        doc.value = 'ten'
+            doc.validate()
-        self.assertRaises(ValidationError, doc.validate)
+        doc.value = "ten"
+        with pytest.raises(ValidationError):
+            doc.validate()
 
     def test_long_ne_operator(self):
         class TestDocument(Document):
@@ -53,4 +54,4 @@ class TestLongField(MongoDBTestCase):
         TestDocument(long_fld=None).save()
         TestDocument(long_fld=1).save()
 
-        self.assertEqual(1, TestDocument.objects(long_fld__ne=None).count())
+        assert 1 == TestDocument.objects(long_fld__ne=None).count()

tests/fields/test_map_field.py

@@ -1,29 +1,31 @@
 # -*- coding: utf-8 -*-
 import datetime
 
-from mongoengine import *
+import pytest
 
+from mongoengine import *
 from tests.utils import MongoDBTestCase
 
 
 class TestMapField(MongoDBTestCase):
-
     def test_mapfield(self):
         """Ensure that the MapField handles the declared type."""
+
         class Simple(Document):
             mapping = MapField(IntField())
 
         Simple.drop_collection()
 
         e = Simple()
-        e.mapping['someint'] = 1
+        e.mapping["someint"] = 1
         e.save()
 
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
-            e.mapping['somestring'] = "abc"
+            e.mapping["somestring"] = "abc"
             e.save()
 
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
+
             class NoDeclaredType(Document):
                 mapping = MapField()
 
@@ -45,38 +47,37 @@ class TestMapField(MongoDBTestCase):
         Extensible.drop_collection()
 
         e = Extensible()
-        e.mapping['somestring'] = StringSetting(value='foo')
+        e.mapping["somestring"] = StringSetting(value="foo")
-        e.mapping['someint'] = IntegerSetting(value=42)
+        e.mapping["someint"] = IntegerSetting(value=42)
         e.save()
 
         e2 = Extensible.objects.get(id=e.id)
-        self.assertIsInstance(e2.mapping['somestring'], StringSetting)
+        assert isinstance(e2.mapping["somestring"], StringSetting)
-        self.assertIsInstance(e2.mapping['someint'], IntegerSetting)
+        assert isinstance(e2.mapping["someint"], IntegerSetting)
 
-        with self.assertRaises(ValidationError):
+        with pytest.raises(ValidationError):
-            e.mapping['someint'] = 123
+            e.mapping["someint"] = 123
             e.save()
 
     def test_embedded_mapfield_db_field(self):
         class Embedded(EmbeddedDocument):
-            number = IntField(default=0, db_field='i')
+            number = IntField(default=0, db_field="i")
 
         class Test(Document):
-            my_map = MapField(field=EmbeddedDocumentField(Embedded),
+            my_map = MapField(field=EmbeddedDocumentField(Embedded), db_field="x")
-                              db_field='x')
 
         Test.drop_collection()
 
         test = Test()
-        test.my_map['DICTIONARY_KEY'] = Embedded(number=1)
+        test.my_map["DICTIONARY_KEY"] = Embedded(number=1)
         test.save()
 
         Test.objects.update_one(inc__my_map__DICTIONARY_KEY__number=1)
 
         test = Test.objects.get()
-        self.assertEqual(test.my_map['DICTIONARY_KEY'].number, 2)
+        assert test.my_map["DICTIONARY_KEY"].number == 2
         doc = self.db.test.find_one()
-        self.assertEqual(doc['x']['DICTIONARY_KEY']['i'], 2)
+        assert doc["x"]["DICTIONARY_KEY"]["i"] == 2
 
     def test_mapfield_numerical_index(self):
         """Ensure that MapField accept numeric strings as indexes."""
@@ -90,9 +91,9 @@ class TestMapField(MongoDBTestCase):
         Test.drop_collection()
 
         test = Test()
-        test.my_map['1'] = Embedded(name='test')
+        test.my_map["1"] = Embedded(name="test")
         test.save()
-        test.my_map['1'].name = 'test updated'
+        test.my_map["1"].name = "test updated"
         test.save()
 
     def test_map_field_lookup(self):
@@ -110,15 +111,20 @@ class TestMapField(MongoDBTestCase):
             actions = MapField(EmbeddedDocumentField(Action))
 
         Log.drop_collection()
-        Log(name="wilson", visited={'friends': datetime.datetime.now()},
+        Log(
-            actions={'friends': Action(operation='drink', object='beer')}).save()
+            name="wilson",
+            visited={"friends": datetime.datetime.now()},
+            actions={"friends": Action(operation="drink", object="beer")},
+        ).save()
 
-        self.assertEqual(1, Log.objects(
+        assert 1 == Log.objects(visited__friends__exists=True).count()
-            visited__friends__exists=True).count())
 
-        self.assertEqual(1, Log.objects(
+        assert (
-            actions__friends__operation='drink',
+            1
-            actions__friends__object='beer').count())
+            == Log.objects(
+                actions__friends__operation="drink", actions__friends__object="beer"
+            ).count()
+        )
 
     def test_map_field_unicode(self):
         class Info(EmbeddedDocument):
@@ -130,15 +136,11 @@ class TestMapField(MongoDBTestCase):
 
         BlogPost.drop_collection()
 
-        tree = BlogPost(info_dict={
+        tree = BlogPost(info_dict={u"éééé": {"description": u"VALUE: éééé"}})
-            u"éééé": {
-                'description': u"VALUE: éééé"
-            }
-        })
 
         tree.save()
 
-        self.assertEqual(
+        assert (
-            BlogPost.objects.get(id=tree.id).info_dict[u"éééé"].description,
+            BlogPost.objects.get(id=tree.id).info_dict[u"éééé"].description
-            u"VALUE: éééé"
+            == u"VALUE: éééé"
         )

tests/fields/test_reference_field.py

@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
-from bson import SON, DBRef
+from bson import DBRef, SON
+import pytest
 
 from mongoengine import *
-
 from tests.utils import MongoDBTestCase
 
 
@@ -24,19 +24,22 @@ class TestReferenceField(MongoDBTestCase):
 
         # Make sure ReferenceField only accepts a document class or a string
         # with a document class name.
-        self.assertRaises(ValidationError, ReferenceField, EmbeddedDocument)
+        with pytest.raises(ValidationError):
+            ReferenceField(EmbeddedDocument)
 
-        user = User(name='Test User')
+        user = User(name="Test User")
 
         # Ensure that the referenced object must have been saved
-        post1 = BlogPost(content='Chips and gravy taste good.')
+        post1 = BlogPost(content="Chips and gravy taste good.")
         post1.author = user
-        self.assertRaises(ValidationError, post1.save)
+        with pytest.raises(ValidationError):
+            post1.save()
 
         # Check that an invalid object type cannot be used
-        post2 = BlogPost(content='Chips and chilli taste good.')
+        post2 = BlogPost(content="Chips and chilli taste good.")
         post1.author = post2
-        self.assertRaises(ValidationError, post1.validate)
+        with pytest.raises(ValidationError):
+            post1.validate()
 
         # Ensure ObjectID's are accepted as references
         user_object_id = user.pk
@@ -52,42 +55,27 @@ class TestReferenceField(MongoDBTestCase):
         # Make sure referencing a saved document of the *wrong* type fails
         post2.save()
         post1.author = post2
-        self.assertRaises(ValidationError, post1.validate)
+        with pytest.raises(ValidationError):
-
+            post1.validate()
-    def test_objectid_reference_fields(self):
-        """Make sure storing Object ID references works."""
-
-        class Person(Document):
-            name = StringField()
-            parent = ReferenceField('self')
-
-        Person.drop_collection()
-
-        p1 = Person(name="John").save()
-        Person(name="Ross", parent=p1.pk).save()
-
-        p = Person.objects.get(name="Ross")
-        self.assertEqual(p.parent, p1)
 
     def test_dbref_reference_fields(self):
         """Make sure storing references as bson.dbref.DBRef works."""
 
         class Person(Document):
             name = StringField()
-            parent = ReferenceField('self', dbref=True)
+            parent = ReferenceField("self", dbref=True)
 
         Person.drop_collection()
 
         p1 = Person(name="John").save()
         Person(name="Ross", parent=p1).save()
 
-        self.assertEqual(
+        assert Person._get_collection().find_one({"name": "Ross"})["parent"] == DBRef(
-            Person._get_collection().find_one({'name': 'Ross'})['parent'],
+            "person", p1.pk
-            DBRef('person', p1.pk)
         )
 
         p = Person.objects.get(name="Ross")
-        self.assertEqual(p.parent, p1)
+        assert p.parent == p1
 
     def test_dbref_to_mongo(self):
         """Make sure that calling to_mongo on a ReferenceField which
@@ -97,21 +85,15 @@ class TestReferenceField(MongoDBTestCase):
 
         class Person(Document):
             name = StringField()
-            parent = ReferenceField('self', dbref=False)
+            parent = ReferenceField("self", dbref=False)
 
-        p = Person(
+        p = Person(name="Steve", parent=DBRef("person", "abcdefghijklmnop"))
-            name='Steve',
+        assert p.to_mongo() == SON([("name", u"Steve"), ("parent", "abcdefghijklmnop")])
-            parent=DBRef('person', 'abcdefghijklmnop')
-        )
-        self.assertEqual(p.to_mongo(), SON([
-            ('name', u'Steve'),
-            ('parent', 'abcdefghijklmnop')
-        ]))
 
     def test_objectid_reference_fields(self):
         class Person(Document):
             name = StringField()
-            parent = ReferenceField('self', dbref=False)
+            parent = ReferenceField("self", dbref=False)
 
         Person.drop_collection()
 
@@ -119,18 +101,19 @@ class TestReferenceField(MongoDBTestCase):
         Person(name="Ross", parent=p1).save()
 
         col = Person._get_collection()
-        data = col.find_one({'name': 'Ross'})
+        data = col.find_one({"name": "Ross"})
-        self.assertEqual(data['parent'], p1.pk)
+        assert data["parent"] == p1.pk
 
         p = Person.objects.get(name="Ross")
-        self.assertEqual(p.parent, p1)
+        assert p.parent == p1
 
     def test_undefined_reference(self):
         """Ensure that ReferenceFields may reference undefined Documents.
         """
+
         class Product(Document):
             name = StringField()
-            company = ReferenceField('Company')
+            company = ReferenceField("Company")
 
         class Company(Document):
             name = StringField()
@@ -138,28 +121,29 @@ class TestReferenceField(MongoDBTestCase):
         Product.drop_collection()
         Company.drop_collection()
 
-        ten_gen = Company(name='10gen')
+        ten_gen = Company(name="10gen")
         ten_gen.save()
-        mongodb = Product(name='MongoDB', company=ten_gen)
+        mongodb = Product(name="MongoDB", company=ten_gen)
         mongodb.save()
 
-        me = Product(name='MongoEngine')
+        me = Product(name="MongoEngine")
         me.save()
 
         obj = Product.objects(company=ten_gen).first()
-        self.assertEqual(obj, mongodb)
+        assert obj == mongodb
-        self.assertEqual(obj.company, ten_gen)
+        assert obj.company == ten_gen
 
         obj = Product.objects(company=None).first()
-        self.assertEqual(obj, me)
+        assert obj == me
 
         obj = Product.objects.get(company=None)
-        self.assertEqual(obj, me)
+        assert obj == me
 
     def test_reference_query_conversion(self):
         """Ensure that ReferenceFields can be queried using objects and values
         of the type of the primary key of the referenced object.
         """
+
         class Member(Document):
             user_num = IntField(primary_key=True)
 
@@ -175,22 +159,23 @@ class TestReferenceField(MongoDBTestCase):
         m2 = Member(user_num=2)
         m2.save()
 
-        post1 = BlogPost(title='post 1', author=m1)
+        post1 = BlogPost(title="post 1", author=m1)
         post1.save()
 
-        post2 = BlogPost(title='post 2', author=m2)
+        post2 = BlogPost(title="post 2", author=m2)
         post2.save()
 
         post = BlogPost.objects(author=m1).first()
-        self.assertEqual(post.id, post1.id)
+        assert post.id == post1.id
 
         post = BlogPost.objects(author=m2).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id
 
     def test_reference_query_conversion_dbref(self):
         """Ensure that ReferenceFields can be queried using objects and values
         of the type of the primary key of the referenced object.
         """
+
         class Member(Document):
             user_num = IntField(primary_key=True)
 
@@ -206,14 +191,14 @@ class TestReferenceField(MongoDBTestCase):
         m2 = Member(user_num=2)
         m2.save()
 
-        post1 = BlogPost(title='post 1', author=m1)
+        post1 = BlogPost(title="post 1", author=m1)
         post1.save()
 
-        post2 = BlogPost(title='post 2', author=m2)
+        post2 = BlogPost(title="post 2", author=m2)
         post2.save()
 
         post = BlogPost.objects(author=m1).first()
-        self.assertEqual(post.id, post1.id)
+        assert post.id == post1.id
 
         post = BlogPost.objects(author=m2).first()
-        self.assertEqual(post.id, post2.id)
+        assert post.id == post2.id

tests/fields/test_sequence_field.py

@@ -11,79 +11,79 @@ class TestSequenceField(MongoDBTestCase):
             id = SequenceField(primary_key=True)
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Person.drop_collection()
 
         for x in range(10):
             Person(name="Person %s" % x).save()
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         ids = [i.id for i in Person.objects]
-        self.assertEqual(ids, range(1, 11))
+        assert ids == list(range(1, 11))
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         Person.id.set_next_value(1000)
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 1000)
+        assert c["next"] == 1000
 
     def test_sequence_field_get_next_value(self):
         class Person(Document):
             id = SequenceField(primary_key=True)
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Person.drop_collection()
 
         for x in range(10):
             Person(name="Person %s" % x).save()
 
-        self.assertEqual(Person.id.get_next_value(), 11)
+        assert Person.id.get_next_value() == 11
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
 
-        self.assertEqual(Person.id.get_next_value(), 1)
+        assert Person.id.get_next_value() == 1
 
         class Person(Document):
             id = SequenceField(primary_key=True, value_decorator=str)
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Person.drop_collection()
 
         for x in range(10):
             Person(name="Person %s" % x).save()
 
-        self.assertEqual(Person.id.get_next_value(), '11')
+        assert Person.id.get_next_value() == "11"
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
 
-        self.assertEqual(Person.id.get_next_value(), '1')
+        assert Person.id.get_next_value() == "1"
 
     def test_sequence_field_sequence_name(self):
         class Person(Document):
-            id = SequenceField(primary_key=True, sequence_name='jelly')
+            id = SequenceField(primary_key=True, sequence_name="jelly")
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Person.drop_collection()
 
         for x in range(10):
             Person(name="Person %s" % x).save()
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'jelly.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "jelly.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         ids = [i.id for i in Person.objects]
-        self.assertEqual(ids, range(1, 11))
+        assert ids == list(range(1, 11))
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'jelly.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "jelly.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         Person.id.set_next_value(1000)
-        c = self.db['mongoengine.counters'].find_one({'_id': 'jelly.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "jelly.id"})
-        self.assertEqual(c['next'], 1000)
+        assert c["next"] == 1000
 
     def test_multiple_sequence_fields(self):
         class Person(Document):
@@ -91,56 +91,56 @@ class TestSequenceField(MongoDBTestCase):
             counter = SequenceField()
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Person.drop_collection()
 
         for x in range(10):
             Person(name="Person %s" % x).save()
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         ids = [i.id for i in Person.objects]
-        self.assertEqual(ids, range(1, 11))
+        assert ids == list(range(1, 11))
 
         counters = [i.counter for i in Person.objects]
-        self.assertEqual(counters, range(1, 11))
+        assert counters == list(range(1, 11))
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         Person.id.set_next_value(1000)
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 1000)
+        assert c["next"] == 1000
 
         Person.counter.set_next_value(999)
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.counter'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.counter"})
-        self.assertEqual(c['next'], 999)
+        assert c["next"] == 999
 
     def test_sequence_fields_reload(self):
         class Animal(Document):
             counter = SequenceField()
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Animal.drop_collection()
 
         a = Animal(name="Boi").save()
 
-        self.assertEqual(a.counter, 1)
+        assert a.counter == 1
         a.reload()
-        self.assertEqual(a.counter, 1)
+        assert a.counter == 1
 
         a.counter = None
-        self.assertEqual(a.counter, 2)
+        assert a.counter == 2
         a.save()
 
-        self.assertEqual(a.counter, 2)
+        assert a.counter == 2
 
         a = Animal.objects.first()
-        self.assertEqual(a.counter, 2)
+        assert a.counter == 2
         a.reload()
-        self.assertEqual(a.counter, 2)
+        assert a.counter == 2
 
     def test_multiple_sequence_fields_on_docs(self):
         class Animal(Document):
@@ -151,7 +151,7 @@ class TestSequenceField(MongoDBTestCase):
             id = SequenceField(primary_key=True)
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Animal.drop_collection()
         Person.drop_collection()
 
@@ -159,44 +159,44 @@ class TestSequenceField(MongoDBTestCase):
             Animal(name="Animal %s" % x).save()
             Person(name="Person %s" % x).save()
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'animal.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "animal.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         ids = [i.id for i in Person.objects]
-        self.assertEqual(ids, range(1, 11))
+        assert ids == list(range(1, 11))
 
         id = [i.id for i in Animal.objects]
-        self.assertEqual(id, range(1, 11))
+        assert id == list(range(1, 11))
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'animal.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "animal.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
     def test_sequence_field_value_decorator(self):
         class Person(Document):
             id = SequenceField(primary_key=True, value_decorator=str)
             name = StringField()
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Person.drop_collection()
 
         for x in range(10):
             p = Person(name="Person %s" % x)
             p.save()
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
         ids = [i.id for i in Person.objects]
-        self.assertEqual(ids, map(str, range(1, 11)))
+        assert ids == [str(i) for i in range(1, 11)]
 
-        c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
+        c = self.db["mongoengine.counters"].find_one({"_id": "person.id"})
-        self.assertEqual(c['next'], 10)
+        assert c["next"] == 10
 
     def test_embedded_sequence_field(self):
         class Comment(EmbeddedDocument):
@@ -207,23 +207,27 @@ class TestSequenceField(MongoDBTestCase):
             title = StringField(required=True)
             comments = ListField(EmbeddedDocumentField(Comment))
 
-        self.db['mongoengine.counters'].drop()
+        self.db["mongoengine.counters"].drop()
         Post.drop_collection()
 
-        Post(title="MongoEngine",
+        Post(
-             comments=[Comment(content="NoSQL Rocks"),
+            title="MongoEngine",
-                       Comment(content="MongoEngine Rocks")]).save()
+            comments=[
-        c = self.db['mongoengine.counters'].find_one({'_id': 'comment.id'})
+                Comment(content="NoSQL Rocks"),
-        self.assertEqual(c['next'], 2)
+                Comment(content="MongoEngine Rocks"),
+            ],
+        ).save()
+        c = self.db["mongoengine.counters"].find_one({"_id": "comment.id"})
+        assert c["next"] == 2
         post = Post.objects.first()
-        self.assertEqual(1, post.comments[0].id)
+        assert 1 == post.comments[0].id
-        self.assertEqual(2, post.comments[1].id)
+        assert 2 == post.comments[1].id
 
     def test_inherited_sequencefield(self):
         class Base(Document):
             name = StringField()
             counter = SequenceField()
-            meta = {'abstract': True}
+            meta = {"abstract": True}
 
         class Foo(Base):
             pass
@@ -231,24 +235,25 @@ class TestSequenceField(MongoDBTestCase):
         class Bar(Base):
             pass
 
-        bar = Bar(name='Bar')
+        bar = Bar(name="Bar")
         bar.save()
 
-        foo = Foo(name='Foo')
+        foo = Foo(name="Foo")
         foo.save()
 
-        self.assertTrue('base.counter' in
+        assert "base.counter" in self.db["mongoengine.counters"].find().distinct("_id")
-                        self.db['mongoengine.counters'].find().distinct('_id'))
+        assert not (
-        self.assertFalse(('foo.counter' or 'bar.counter') in
+            ("foo.counter" or "bar.counter")
-                         self.db['mongoengine.counters'].find().distinct('_id'))
+            in self.db["mongoengine.counters"].find().distinct("_id")
-        self.assertNotEqual(foo.counter, bar.counter)
+        )
-        self.assertEqual(foo._fields['counter'].owner_document, Base)
+        assert foo.counter != bar.counter
-        self.assertEqual(bar._fields['counter'].owner_document, Base)
+        assert foo._fields["counter"].owner_document == Base
+        assert bar._fields["counter"].owner_document == Base
 
     def test_no_inherited_sequencefield(self):
         class Base(Document):
             name = StringField()
-            meta = {'abstract': True}
+            meta = {"abstract": True}
 
         class Foo(Base):
             counter = SequenceField()
@@ -256,16 +261,18 @@ class TestSequenceField(MongoDBTestCase):
         class Bar(Base):
             counter = SequenceField()
 
-        bar = Bar(name='Bar')
+        bar = Bar(name="Bar")
         bar.save()
 
-        foo = Foo(name='Foo')
+        foo = Foo(name="Foo")
         foo.save()
 
-        self.assertFalse('base.counter' in
+        assert "base.counter" not in self.db["mongoengine.counters"].find().distinct(
-                         self.db['mongoengine.counters'].find().distinct('_id'))
+            "_id"
-        self.assertTrue(('foo.counter' and 'bar.counter') in
+        )
-                         self.db['mongoengine.counters'].find().distinct('_id'))
+        existing_counters = self.db["mongoengine.counters"].find().distinct("_id")
-        self.assertEqual(foo.counter, bar.counter)
+        assert "foo.counter" in existing_counters
-        self.assertEqual(foo._fields['counter'].owner_document, Foo)
+        assert "bar.counter" in existing_counters
-        self.assertEqual(bar._fields['counter'].owner_document, Bar)
+        assert foo.counter == bar.counter
+        assert foo._fields["counter"].owner_document == Foo
+        assert bar._fields["counter"].owner_document == Bar

tests/fields/test_url_field.py

@@ -1,53 +1,60 @@
 # -*- coding: utf-8 -*-
-from mongoengine import *
+import pytest
 
+from mongoengine import *
 from tests.utils import MongoDBTestCase
 
 
 class TestURLField(MongoDBTestCase):
-
     def test_validation(self):
         """Ensure that URLFields validate urls properly."""
+
         class Link(Document):
             url = URLField()
 
         link = Link()
-        link.url = 'google'
+        link.url = "google"
-        self.assertRaises(ValidationError, link.validate)
+        with pytest.raises(ValidationError):
+            link.validate()
 
-        link.url = 'http://www.google.com:8080'
+        link.url = "http://www.google.com:8080"
         link.validate()
 
     def test_unicode_url_validation(self):
         """Ensure unicode URLs are validated properly."""
+
         class Link(Document):
             url = URLField()
 
         link = Link()
-        link.url = u'http://привет.com'
+        link.url = u"http://привет.com"
 
         # TODO fix URL validation - this *IS* a valid URL
         # For now we just want to make sure that the error message is correct
-        with self.assertRaises(ValidationError) as ctx_err:
+        with pytest.raises(ValidationError) as exc_info:
             link.validate()
-        self.assertEqual(unicode(ctx_err.exception),
+        assert (
-                         u"ValidationError (Link:None) (Invalid URL: http://\u043f\u0440\u0438\u0432\u0435\u0442.com: ['url'])")
+            str(exc_info.value)
+            == u"ValidationError (Link:None) (Invalid URL: http://\u043f\u0440\u0438\u0432\u0435\u0442.com: ['url'])"
+        )
 
     def test_url_scheme_validation(self):
         """Ensure that URLFields validate urls with specific schemes properly.
         """
+
         class Link(Document):
             url = URLField()
 
         class SchemeLink(Document):
-            url = URLField(schemes=['ws', 'irc'])
+            url = URLField(schemes=["ws", "irc"])
 
         link = Link()
-        link.url = 'ws://google.com'
+        link.url = "ws://google.com"
-        self.assertRaises(ValidationError, link.validate)
+        with pytest.raises(ValidationError):
+            link.validate()
 
         scheme_link = SchemeLink()
-        scheme_link.url = 'ws://google.com'
+        scheme_link.url = "ws://google.com"
         scheme_link.validate()
 
     def test_underscore_allowed_in_domains_names(self):
@@ -55,5 +62,5 @@ class TestURLField(MongoDBTestCase):
             url = URLField()
 
         link = Link()
-        link.url = 'https://san_leandro-ca.geebo.com'
+        link.url = "https://san_leandro-ca.geebo.com"
         link.validate()

tests/fields/test_uuid_field.py

@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
 import uuid
 
-from mongoengine import *
+import pytest
 
+from mongoengine import *
 from tests.utils import MongoDBTestCase, get_as_pymongo
 
 
@@ -14,12 +15,7 @@ class TestUUIDField(MongoDBTestCase):
     def test_storage(self):
         uid = uuid.uuid4()
         person = Person(api_key=uid).save()
-        self.assertEqual(
+        assert get_as_pymongo(person) == {"_id": person.id, "api_key": str(uid)}
-            get_as_pymongo(person),
-            {'_id': person.id,
-             'api_key': str(uid)
-             }
-            )
 
     def test_field_string(self):
         """Test UUID fields storing as String
@@ -28,8 +24,8 @@ class TestUUIDField(MongoDBTestCase):
 
         uu = uuid.uuid4()
         Person(api_key=uu).save()
-        self.assertEqual(1, Person.objects(api_key=uu).count())
+        assert 1 == Person.objects(api_key=uu).count()
-        self.assertEqual(uu, Person.objects.first().api_key)
+        assert uu == Person.objects.first().api_key
 
         person = Person()
         valid = (uuid.uuid4(), uuid.uuid1())
@@ -37,11 +33,14 @@ class TestUUIDField(MongoDBTestCase):
             person.api_key = api_key
             person.validate()
 
-        invalid = ('9d159858-549b-4975-9f98-dd2f987c113g',
+        invalid = (
-                   '9d159858-549b-4975-9f98-dd2f987c113')
+            "9d159858-549b-4975-9f98-dd2f987c113g",
+            "9d159858-549b-4975-9f98-dd2f987c113",
+        )
         for api_key in invalid:
             person.api_key = api_key
-            self.assertRaises(ValidationError, person.validate)
+            with pytest.raises(ValidationError):
+                person.validate()
 
     def test_field_binary(self):
         """Test UUID fields storing as Binary object."""
@@ -49,8 +48,8 @@ class TestUUIDField(MongoDBTestCase):
 
         uu = uuid.uuid4()
         Person(api_key=uu).save()
-        self.assertEqual(1, Person.objects(api_key=uu).count())
+        assert 1 == Person.objects(api_key=uu).count()
-        self.assertEqual(uu, Person.objects.first().api_key)
+        assert uu == Person.objects.first().api_key
 
         person = Person()
         valid = (uuid.uuid4(), uuid.uuid1())
@@ -58,8 +57,11 @@ class TestUUIDField(MongoDBTestCase):
             person.api_key = api_key
             person.validate()
 
-        invalid = ('9d159858-549b-4975-9f98-dd2f987c113g',
+        invalid = (
-                   '9d159858-549b-4975-9f98-dd2f987c113')
+            "9d159858-549b-4975-9f98-dd2f987c113g",
+            "9d159858-549b-4975-9f98-dd2f987c113",
+        )
         for api_key in invalid:
             person.api_key = api_key
-            self.assertRaises(ValidationError, person.validate)
+            with pytest.raises(ValidationError):
+                person.validate()

tests/fixtures.py

@@ -11,7 +11,7 @@ class PickleEmbedded(EmbeddedDocument):
 
 class PickleTest(Document):
     number = IntField()
-    string = StringField(choices=(('One', '1'), ('Two', '2')))
+    string = StringField(choices=(("One", "1"), ("Two", "2")))
     embedded = EmbeddedDocumentField(PickleEmbedded)
     lists = ListField(StringField())
     photo = FileField()
@@ -19,7 +19,7 @@ class PickleTest(Document):
 
 class NewDocumentPickleTest(Document):
     number = IntField()
-    string = StringField(choices=(('One', '1'), ('Two', '2')))
+    string = StringField(choices=(("One", "1"), ("Two", "2")))
     embedded = EmbeddedDocumentField(PickleEmbedded)
     lists = ListField(StringField())
     photo = FileField()
@@ -36,17 +36,17 @@ class PickleDynamicTest(DynamicDocument):
 
 class PickleSignalsTest(Document):
     number = IntField()
-    string = StringField(choices=(('One', '1'), ('Two', '2')))
+    string = StringField(choices=(("One", "1"), ("Two", "2")))
     embedded = EmbeddedDocumentField(PickleEmbedded)
     lists = ListField(StringField())
 
     @classmethod
     def post_save(self, sender, document, created, **kwargs):
-        pickled = pickle.dumps(document)
+        pickle.dumps(document)
 
     @classmethod
     def post_delete(self, sender, document, **kwargs):
-        pickled = pickle.dumps(document)
+        pickle.dumps(document)
 
 
 signals.post_save.connect(PickleSignalsTest.post_save, sender=PickleSignalsTest)
@@ -58,4 +58,4 @@ class Mixin(object):
 
 
 class Base(Document):
-    meta = {'allow_inheritance': True}
+    meta = {"allow_inheritance": True}

tests/queryset/__init__.py

@@ -1,6 +0,0 @@
-from .transform import *
-from .field_list import *
-from .queryset import *
-from .visitor import *
-from .geo import *
-from .modify import *

tests/queryset/field_list.py

@@ -1,440 +0,0 @@
-import unittest
-
-from mongoengine import *
-from mongoengine.queryset import QueryFieldList
-
-__all__ = ("QueryFieldListTest", "OnlyExcludeAllTest")
-
-
-class QueryFieldListTest(unittest.TestCase):
-
-    def test_empty(self):
-        q = QueryFieldList()
-        self.assertFalse(q)
-
-        q = QueryFieldList(always_include=['_cls'])
-        self.assertFalse(q)
-
-    def test_include_include(self):
-        q = QueryFieldList()
-        q += QueryFieldList(fields=['a', 'b'], value=QueryFieldList.ONLY, _only_called=True)
-        self.assertEqual(q.as_dict(), {'a': 1, 'b': 1})
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.ONLY)
-        self.assertEqual(q.as_dict(), {'a': 1, 'b': 1, 'c': 1})
-
-    def test_include_exclude(self):
-        q = QueryFieldList()
-        q += QueryFieldList(fields=['a', 'b'], value=QueryFieldList.ONLY)
-        self.assertEqual(q.as_dict(), {'a': 1, 'b': 1})
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.EXCLUDE)
-        self.assertEqual(q.as_dict(), {'a': 1})
-
-    def test_exclude_exclude(self):
-        q = QueryFieldList()
-        q += QueryFieldList(fields=['a', 'b'], value=QueryFieldList.EXCLUDE)
-        self.assertEqual(q.as_dict(), {'a': 0, 'b': 0})
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.EXCLUDE)
-        self.assertEqual(q.as_dict(), {'a': 0, 'b': 0, 'c': 0})
-
-    def test_exclude_include(self):
-        q = QueryFieldList()
-        q += QueryFieldList(fields=['a', 'b'], value=QueryFieldList.EXCLUDE)
-        self.assertEqual(q.as_dict(), {'a': 0, 'b': 0})
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.ONLY)
-        self.assertEqual(q.as_dict(), {'c': 1})
-
-    def test_always_include(self):
-        q = QueryFieldList(always_include=['x', 'y'])
-        q += QueryFieldList(fields=['a', 'b', 'x'], value=QueryFieldList.EXCLUDE)
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.ONLY)
-        self.assertEqual(q.as_dict(), {'x': 1, 'y': 1, 'c': 1})
-
-    def test_reset(self):
-        q = QueryFieldList(always_include=['x', 'y'])
-        q += QueryFieldList(fields=['a', 'b', 'x'], value=QueryFieldList.EXCLUDE)
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.ONLY)
-        self.assertEqual(q.as_dict(), {'x': 1, 'y': 1, 'c': 1})
-        q.reset()
-        self.assertFalse(q)
-        q += QueryFieldList(fields=['b', 'c'], value=QueryFieldList.ONLY)
-        self.assertEqual(q.as_dict(), {'x': 1, 'y': 1, 'b': 1, 'c': 1})
-
-    def test_using_a_slice(self):
-        q = QueryFieldList()
-        q += QueryFieldList(fields=['a'], value={"$slice": 5})
-        self.assertEqual(q.as_dict(), {'a': {"$slice": 5}})
-
-
-class OnlyExcludeAllTest(unittest.TestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-
-        class Person(Document):
-            name = StringField()
-            age = IntField()
-            meta = {'allow_inheritance': True}
-
-        Person.drop_collection()
-        self.Person = Person
-
-    def test_mixing_only_exclude(self):
-
-        class MyDoc(Document):
-            a = StringField()
-            b = StringField()
-            c = StringField()
-            d = StringField()
-            e = StringField()
-            f = StringField()
-
-        include = ['a', 'b', 'c', 'd', 'e']
-        exclude = ['d', 'e']
-        only = ['b', 'c']
-
-        qs = MyDoc.objects.fields(**{i: 1 for i in include})
-        self.assertEqual(qs._loaded_fields.as_dict(),
-                         {'a': 1, 'b': 1, 'c': 1, 'd': 1, 'e': 1})
-        qs = qs.only(*only)
-        self.assertEqual(qs._loaded_fields.as_dict(), {'b': 1, 'c': 1})
-        qs = qs.exclude(*exclude)
-        self.assertEqual(qs._loaded_fields.as_dict(), {'b': 1, 'c': 1})
-
-        qs = MyDoc.objects.fields(**{i: 1 for i in include})
-        qs = qs.exclude(*exclude)
-        self.assertEqual(qs._loaded_fields.as_dict(), {'a': 1, 'b': 1, 'c': 1})
-        qs = qs.only(*only)
-        self.assertEqual(qs._loaded_fields.as_dict(), {'b': 1, 'c': 1})
-
-        qs = MyDoc.objects.exclude(*exclude)
-        qs = qs.fields(**{i: 1 for i in include})
-        self.assertEqual(qs._loaded_fields.as_dict(), {'a': 1, 'b': 1, 'c': 1})
-        qs = qs.only(*only)
-        self.assertEqual(qs._loaded_fields.as_dict(), {'b': 1, 'c': 1})
-
-    def test_slicing(self):
-
-        class MyDoc(Document):
-            a = ListField()
-            b = ListField()
-            c = ListField()
-            d = ListField()
-            e = ListField()
-            f = ListField()
-
-        include = ['a', 'b', 'c', 'd', 'e']
-        exclude = ['d', 'e']
-        only = ['b', 'c']
-
-        qs = MyDoc.objects.fields(**{i: 1 for i in include})
-        qs = qs.exclude(*exclude)
-        qs = qs.only(*only)
-        qs = qs.fields(slice__b=5)
-        self.assertEqual(qs._loaded_fields.as_dict(),
-                         {'b': {'$slice': 5}, 'c': 1})
-
-        qs = qs.fields(slice__c=[5, 1])
-        self.assertEqual(qs._loaded_fields.as_dict(),
-                         {'b': {'$slice': 5}, 'c': {'$slice': [5, 1]}})
-
-        qs = qs.exclude('c')
-        self.assertEqual(qs._loaded_fields.as_dict(),
-                         {'b': {'$slice': 5}})
-
-    def test_mix_slice_with_other_fields(self):
-        class MyDoc(Document):
-            a = ListField()
-            b = ListField()
-            c = ListField()
-
-        qs = MyDoc.objects.fields(a=1, b=0, slice__c=2)
-        self.assertEqual(qs._loaded_fields.as_dict(),
-                         {'c': {'$slice': 2}, 'a': 1})
-
-    def test_only(self):
-        """Ensure that QuerySet.only only returns the requested fields.
-        """
-        person = self.Person(name='test', age=25)
-        person.save()
-
-        obj = self.Person.objects.only('name').get()
-        self.assertEqual(obj.name, person.name)
-        self.assertEqual(obj.age, None)
-
-        obj = self.Person.objects.only('age').get()
-        self.assertEqual(obj.name, None)
-        self.assertEqual(obj.age, person.age)
-
-        obj = self.Person.objects.only('name', 'age').get()
-        self.assertEqual(obj.name, person.name)
-        self.assertEqual(obj.age, person.age)
-
-        obj = self.Person.objects.only(*('id', 'name',)).get()
-        self.assertEqual(obj.name, person.name)
-        self.assertEqual(obj.age, None)
-
-        # Check polymorphism still works
-        class Employee(self.Person):
-            salary = IntField(db_field='wage')
-
-        employee = Employee(name='test employee', age=40, salary=30000)
-        employee.save()
-
-        obj = self.Person.objects(id=employee.id).only('age').get()
-        self.assertIsInstance(obj, Employee)
-
-        # Check field names are looked up properly
-        obj = Employee.objects(id=employee.id).only('salary').get()
-        self.assertEqual(obj.salary, employee.salary)
-        self.assertEqual(obj.name, None)
-
-    def test_only_with_subfields(self):
-        class User(EmbeddedDocument):
-            name = StringField()
-            email = StringField()
-
-        class Comment(EmbeddedDocument):
-            title = StringField()
-            text = StringField()
-
-        class VariousData(EmbeddedDocument):
-            some = BooleanField()
-
-        class BlogPost(Document):
-            content = StringField()
-            author = EmbeddedDocumentField(User)
-            comments = ListField(EmbeddedDocumentField(Comment))
-            various = MapField(field=EmbeddedDocumentField(VariousData))
-
-        BlogPost.drop_collection()
-
-        post = BlogPost(content='Had a good coffee today...', various={'test_dynamic': {'some': True}})
-        post.author = User(name='Test User')
-        post.comments = [Comment(title='I aggree', text='Great post!'), Comment(title='Coffee', text='I hate coffee')]
-        post.save()
-
-        obj = BlogPost.objects.only('author.name',).get()
-        self.assertEqual(obj.content, None)
-        self.assertEqual(obj.author.email, None)
-        self.assertEqual(obj.author.name, 'Test User')
-        self.assertEqual(obj.comments, [])
-
-        obj = BlogPost.objects.only('various.test_dynamic.some').get()
-        self.assertEqual(obj.various["test_dynamic"].some, True)
-
-        obj = BlogPost.objects.only('content', 'comments.title',).get()
-        self.assertEqual(obj.content, 'Had a good coffee today...')
-        self.assertEqual(obj.author, None)
-        self.assertEqual(obj.comments[0].title, 'I aggree')
-        self.assertEqual(obj.comments[1].title, 'Coffee')
-        self.assertEqual(obj.comments[0].text, None)
-        self.assertEqual(obj.comments[1].text, None)
-
-        obj = BlogPost.objects.only('comments',).get()
-        self.assertEqual(obj.content, None)
-        self.assertEqual(obj.author, None)
-        self.assertEqual(obj.comments[0].title, 'I aggree')
-        self.assertEqual(obj.comments[1].title, 'Coffee')
-        self.assertEqual(obj.comments[0].text, 'Great post!')
-        self.assertEqual(obj.comments[1].text, 'I hate coffee')
-
-        BlogPost.drop_collection()
-
-    def test_exclude(self):
-        class User(EmbeddedDocument):
-            name = StringField()
-            email = StringField()
-
-        class Comment(EmbeddedDocument):
-            title = StringField()
-            text = StringField()
-
-        class BlogPost(Document):
-            content = StringField()
-            author = EmbeddedDocumentField(User)
-            comments = ListField(EmbeddedDocumentField(Comment))
-
-        BlogPost.drop_collection()
-
-        post = BlogPost(content='Had a good coffee today...')
-        post.author = User(name='Test User')
-        post.comments = [Comment(title='I aggree', text='Great post!'), Comment(title='Coffee', text='I hate coffee')]
-        post.save()
-
-        obj = BlogPost.objects.exclude('author', 'comments.text').get()
-        self.assertEqual(obj.author, None)
-        self.assertEqual(obj.content, 'Had a good coffee today...')
-        self.assertEqual(obj.comments[0].title, 'I aggree')
-        self.assertEqual(obj.comments[0].text, None)
-
-        BlogPost.drop_collection()
-
-    def test_exclude_only_combining(self):
-        class Attachment(EmbeddedDocument):
-            name = StringField()
-            content = StringField()
-
-        class Email(Document):
-            sender = StringField()
-            to = StringField()
-            subject = StringField()
-            body = StringField()
-            content_type = StringField()
-            attachments = ListField(EmbeddedDocumentField(Attachment))
-
-        Email.drop_collection()
-        email = Email(sender='me', to='you', subject='From Russia with Love', body='Hello!', content_type='text/plain')
-        email.attachments = [
-            Attachment(name='file1.doc', content='ABC'),
-            Attachment(name='file2.doc', content='XYZ'),
-        ]
-        email.save()
-
-        obj = Email.objects.exclude('content_type').exclude('body').get()
-        self.assertEqual(obj.sender, 'me')
-        self.assertEqual(obj.to, 'you')
-        self.assertEqual(obj.subject, 'From Russia with Love')
-        self.assertEqual(obj.body, None)
-        self.assertEqual(obj.content_type, None)
-
-        obj = Email.objects.only('sender', 'to').exclude('body', 'sender').get()
-        self.assertEqual(obj.sender, None)
-        self.assertEqual(obj.to, 'you')
-        self.assertEqual(obj.subject, None)
-        self.assertEqual(obj.body, None)
-        self.assertEqual(obj.content_type, None)
-
-        obj = Email.objects.exclude('attachments.content').exclude('body').only('to', 'attachments.name').get()
-        self.assertEqual(obj.attachments[0].name, 'file1.doc')
-        self.assertEqual(obj.attachments[0].content, None)
-        self.assertEqual(obj.sender, None)
-        self.assertEqual(obj.to, 'you')
-        self.assertEqual(obj.subject, None)
-        self.assertEqual(obj.body, None)
-        self.assertEqual(obj.content_type, None)
-
-        Email.drop_collection()
-
-    def test_all_fields(self):
-
-        class Email(Document):
-            sender = StringField()
-            to = StringField()
-            subject = StringField()
-            body = StringField()
-            content_type = StringField()
-
-        Email.drop_collection()
-
-        email = Email(sender='me', to='you', subject='From Russia with Love', body='Hello!', content_type='text/plain')
-        email.save()
-
-        obj = Email.objects.exclude('content_type', 'body').only('to', 'body').all_fields().get()
-        self.assertEqual(obj.sender, 'me')
-        self.assertEqual(obj.to, 'you')
-        self.assertEqual(obj.subject, 'From Russia with Love')
-        self.assertEqual(obj.body, 'Hello!')
-        self.assertEqual(obj.content_type, 'text/plain')
-
-        Email.drop_collection()
-
-    def test_slicing_fields(self):
-        """Ensure that query slicing an array works.
-        """
-        class Numbers(Document):
-            n = ListField(IntField())
-
-        Numbers.drop_collection()
-
-        numbers = Numbers(n=[0, 1, 2, 3, 4, 5, -5, -4, -3, -2, -1])
-        numbers.save()
-
-        # first three
-        numbers = Numbers.objects.fields(slice__n=3).get()
-        self.assertEqual(numbers.n, [0, 1, 2])
-
-        # last three
-        numbers = Numbers.objects.fields(slice__n=-3).get()
-        self.assertEqual(numbers.n, [-3, -2, -1])
-
-        # skip 2, limit 3
-        numbers = Numbers.objects.fields(slice__n=[2, 3]).get()
-        self.assertEqual(numbers.n, [2, 3, 4])
-
-        # skip to fifth from last, limit 4
-        numbers = Numbers.objects.fields(slice__n=[-5, 4]).get()
-        self.assertEqual(numbers.n, [-5, -4, -3, -2])
-
-        # skip to fifth from last, limit 10
-        numbers = Numbers.objects.fields(slice__n=[-5, 10]).get()
-        self.assertEqual(numbers.n, [-5, -4, -3, -2, -1])
-
-        # skip to fifth from last, limit 10 dict method
-        numbers = Numbers.objects.fields(n={"$slice": [-5, 10]}).get()
-        self.assertEqual(numbers.n, [-5, -4, -3, -2, -1])
-
-    def test_slicing_nested_fields(self):
-        """Ensure that query slicing an embedded array works.
-        """
-
-        class EmbeddedNumber(EmbeddedDocument):
-            n = ListField(IntField())
-
-        class Numbers(Document):
-            embedded = EmbeddedDocumentField(EmbeddedNumber)
-
-        Numbers.drop_collection()
-
-        numbers = Numbers()
-        numbers.embedded = EmbeddedNumber(n=[0, 1, 2, 3, 4, 5, -5, -4, -3, -2, -1])
-        numbers.save()
-
-        # first three
-        numbers = Numbers.objects.fields(slice__embedded__n=3).get()
-        self.assertEqual(numbers.embedded.n, [0, 1, 2])
-
-        # last three
-        numbers = Numbers.objects.fields(slice__embedded__n=-3).get()
-        self.assertEqual(numbers.embedded.n, [-3, -2, -1])
-
-        # skip 2, limit 3
-        numbers = Numbers.objects.fields(slice__embedded__n=[2, 3]).get()
-        self.assertEqual(numbers.embedded.n, [2, 3, 4])
-
-        # skip to fifth from last, limit 4
-        numbers = Numbers.objects.fields(slice__embedded__n=[-5, 4]).get()
-        self.assertEqual(numbers.embedded.n, [-5, -4, -3, -2])
-
-        # skip to fifth from last, limit 10
-        numbers = Numbers.objects.fields(slice__embedded__n=[-5, 10]).get()
-        self.assertEqual(numbers.embedded.n, [-5, -4, -3, -2, -1])
-
-        # skip to fifth from last, limit 10 dict method
-        numbers = Numbers.objects.fields(embedded__n={"$slice": [-5, 10]}).get()
-        self.assertEqual(numbers.embedded.n, [-5, -4, -3, -2, -1])
-
-    def test_exclude_from_subclasses_docs(self):
-
-        class Base(Document):
-            username = StringField()
-
-            meta = {'allow_inheritance': True}
-
-        class Anon(Base):
-            anon = BooleanField()
-
-        class User(Base):
-            password = StringField()
-            wibble = StringField()
-
-        Base.drop_collection()
-        User(username="mongodb", password="secret").save()
-
-        user = Base.objects().exclude("password", "wibble").first()
-        self.assertEqual(user.password, None)
-
-        self.assertRaises(LookUpError, Base.objects.exclude, "made_up")
-
-
-if __name__ == '__main__':
-    unittest.main()

tests/queryset/test_field_list.py

@@ -0,0 +1,467 @@
+import unittest
+
+import pytest
+
+from mongoengine import *
+from mongoengine.queryset import QueryFieldList
+
+
+class TestQueryFieldList:
+    def test_empty(self):
+        q = QueryFieldList()
+        assert not q
+
+        q = QueryFieldList(always_include=["_cls"])
+        assert not q
+
+    def test_include_include(self):
+        q = QueryFieldList()
+        q += QueryFieldList(
+            fields=["a", "b"], value=QueryFieldList.ONLY, _only_called=True
+        )
+        assert q.as_dict() == {"a": 1, "b": 1}
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.ONLY)
+        assert q.as_dict() == {"a": 1, "b": 1, "c": 1}
+
+    def test_include_exclude(self):
+        q = QueryFieldList()
+        q += QueryFieldList(fields=["a", "b"], value=QueryFieldList.ONLY)
+        assert q.as_dict() == {"a": 1, "b": 1}
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.EXCLUDE)
+        assert q.as_dict() == {"a": 1}
+
+    def test_exclude_exclude(self):
+        q = QueryFieldList()
+        q += QueryFieldList(fields=["a", "b"], value=QueryFieldList.EXCLUDE)
+        assert q.as_dict() == {"a": 0, "b": 0}
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.EXCLUDE)
+        assert q.as_dict() == {"a": 0, "b": 0, "c": 0}
+
+    def test_exclude_include(self):
+        q = QueryFieldList()
+        q += QueryFieldList(fields=["a", "b"], value=QueryFieldList.EXCLUDE)
+        assert q.as_dict() == {"a": 0, "b": 0}
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.ONLY)
+        assert q.as_dict() == {"c": 1}
+
+    def test_always_include(self):
+        q = QueryFieldList(always_include=["x", "y"])
+        q += QueryFieldList(fields=["a", "b", "x"], value=QueryFieldList.EXCLUDE)
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.ONLY)
+        assert q.as_dict() == {"x": 1, "y": 1, "c": 1}
+
+    def test_reset(self):
+        q = QueryFieldList(always_include=["x", "y"])
+        q += QueryFieldList(fields=["a", "b", "x"], value=QueryFieldList.EXCLUDE)
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.ONLY)
+        assert q.as_dict() == {"x": 1, "y": 1, "c": 1}
+        q.reset()
+        assert not q
+        q += QueryFieldList(fields=["b", "c"], value=QueryFieldList.ONLY)
+        assert q.as_dict() == {"x": 1, "y": 1, "b": 1, "c": 1}
+
+    def test_using_a_slice(self):
+        q = QueryFieldList()
+        q += QueryFieldList(fields=["a"], value={"$slice": 5})
+        assert q.as_dict() == {"a": {"$slice": 5}}
+
+
+class TestOnlyExcludeAll(unittest.TestCase):
+    def setUp(self):
+        connect(db="mongoenginetest")
+
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+            meta = {"allow_inheritance": True}
+
+        Person.drop_collection()
+        self.Person = Person
+
+    def test_mixing_only_exclude(self):
+        class MyDoc(Document):
+            a = StringField()
+            b = StringField()
+            c = StringField()
+            d = StringField()
+            e = StringField()
+            f = StringField()
+
+        include = ["a", "b", "c", "d", "e"]
+        exclude = ["d", "e"]
+        only = ["b", "c"]
+
+        qs = MyDoc.objects.fields(**{i: 1 for i in include})
+        assert qs._loaded_fields.as_dict() == {"a": 1, "b": 1, "c": 1, "d": 1, "e": 1}
+        qs = qs.only(*only)
+        assert qs._loaded_fields.as_dict() == {"b": 1, "c": 1}
+        qs = qs.exclude(*exclude)
+        assert qs._loaded_fields.as_dict() == {"b": 1, "c": 1}
+
+        qs = MyDoc.objects.fields(**{i: 1 for i in include})
+        qs = qs.exclude(*exclude)
+        assert qs._loaded_fields.as_dict() == {"a": 1, "b": 1, "c": 1}
+        qs = qs.only(*only)
+        assert qs._loaded_fields.as_dict() == {"b": 1, "c": 1}
+
+        qs = MyDoc.objects.exclude(*exclude)
+        qs = qs.fields(**{i: 1 for i in include})
+        assert qs._loaded_fields.as_dict() == {"a": 1, "b": 1, "c": 1}
+        qs = qs.only(*only)
+        assert qs._loaded_fields.as_dict() == {"b": 1, "c": 1}
+
+    def test_slicing(self):
+        class MyDoc(Document):
+            a = ListField()
+            b = ListField()
+            c = ListField()
+            d = ListField()
+            e = ListField()
+            f = ListField()
+
+        include = ["a", "b", "c", "d", "e"]
+        exclude = ["d", "e"]
+        only = ["b", "c"]
+
+        qs = MyDoc.objects.fields(**{i: 1 for i in include})
+        qs = qs.exclude(*exclude)
+        qs = qs.only(*only)
+        qs = qs.fields(slice__b=5)
+        assert qs._loaded_fields.as_dict() == {"b": {"$slice": 5}, "c": 1}
+
+        qs = qs.fields(slice__c=[5, 1])
+        assert qs._loaded_fields.as_dict() == {
+            "b": {"$slice": 5},
+            "c": {"$slice": [5, 1]},
+        }
+
+        qs = qs.exclude("c")
+        assert qs._loaded_fields.as_dict() == {"b": {"$slice": 5}}
+
+    def test_mix_slice_with_other_fields(self):
+        class MyDoc(Document):
+            a = ListField()
+            b = ListField()
+            c = ListField()
+
+        qs = MyDoc.objects.fields(a=1, b=0, slice__c=2)
+        assert qs._loaded_fields.as_dict() == {"c": {"$slice": 2}, "a": 1}
+
+    def test_only(self):
+        """Ensure that QuerySet.only only returns the requested fields.
+        """
+        person = self.Person(name="test", age=25)
+        person.save()
+
+        obj = self.Person.objects.only("name").get()
+        assert obj.name == person.name
+        assert obj.age is None
+
+        obj = self.Person.objects.only("age").get()
+        assert obj.name is None
+        assert obj.age == person.age
+
+        obj = self.Person.objects.only("name", "age").get()
+        assert obj.name == person.name
+        assert obj.age == person.age
+
+        obj = self.Person.objects.only(*("id", "name")).get()
+        assert obj.name == person.name
+        assert obj.age is None
+
+        # Check polymorphism still works
+        class Employee(self.Person):
+            salary = IntField(db_field="wage")
+
+        employee = Employee(name="test employee", age=40, salary=30000)
+        employee.save()
+
+        obj = self.Person.objects(id=employee.id).only("age").get()
+        assert isinstance(obj, Employee)
+
+        # Check field names are looked up properly
+        obj = Employee.objects(id=employee.id).only("salary").get()
+        assert obj.salary == employee.salary
+        assert obj.name is None
+
+    def test_only_with_subfields(self):
+        class User(EmbeddedDocument):
+            name = StringField()
+            email = StringField()
+
+        class Comment(EmbeddedDocument):
+            title = StringField()
+            text = StringField()
+
+        class VariousData(EmbeddedDocument):
+            some = BooleanField()
+
+        class BlogPost(Document):
+            content = StringField()
+            author = EmbeddedDocumentField(User)
+            comments = ListField(EmbeddedDocumentField(Comment))
+            various = MapField(field=EmbeddedDocumentField(VariousData))
+
+        BlogPost.drop_collection()
+
+        post = BlogPost(
+            content="Had a good coffee today...",
+            various={"test_dynamic": {"some": True}},
+        )
+        post.author = User(name="Test User")
+        post.comments = [
+            Comment(title="I aggree", text="Great post!"),
+            Comment(title="Coffee", text="I hate coffee"),
+        ]
+        post.save()
+
+        obj = BlogPost.objects.only("author.name").get()
+        assert obj.content is None
+        assert obj.author.email is None
+        assert obj.author.name == "Test User"
+        assert obj.comments == []
+
+        obj = BlogPost.objects.only("various.test_dynamic.some").get()
+        assert obj.various["test_dynamic"].some is True
+
+        obj = BlogPost.objects.only("content", "comments.title").get()
+        assert obj.content == "Had a good coffee today..."
+        assert obj.author is None
+        assert obj.comments[0].title == "I aggree"
+        assert obj.comments[1].title == "Coffee"
+        assert obj.comments[0].text is None
+        assert obj.comments[1].text is None
+
+        obj = BlogPost.objects.only("comments").get()
+        assert obj.content is None
+        assert obj.author is None
+        assert obj.comments[0].title == "I aggree"
+        assert obj.comments[1].title == "Coffee"
+        assert obj.comments[0].text == "Great post!"
+        assert obj.comments[1].text == "I hate coffee"
+
+        BlogPost.drop_collection()
+
+    def test_exclude(self):
+        class User(EmbeddedDocument):
+            name = StringField()
+            email = StringField()
+
+        class Comment(EmbeddedDocument):
+            title = StringField()
+            text = StringField()
+
+        class BlogPost(Document):
+            content = StringField()
+            author = EmbeddedDocumentField(User)
+            comments = ListField(EmbeddedDocumentField(Comment))
+
+        BlogPost.drop_collection()
+
+        post = BlogPost(content="Had a good coffee today...")
+        post.author = User(name="Test User")
+        post.comments = [
+            Comment(title="I aggree", text="Great post!"),
+            Comment(title="Coffee", text="I hate coffee"),
+        ]
+        post.save()
+
+        obj = BlogPost.objects.exclude("author", "comments.text").get()
+        assert obj.author is None
+        assert obj.content == "Had a good coffee today..."
+        assert obj.comments[0].title == "I aggree"
+        assert obj.comments[0].text is None
+
+        BlogPost.drop_collection()
+
+    def test_exclude_only_combining(self):
+        class Attachment(EmbeddedDocument):
+            name = StringField()
+            content = StringField()
+
+        class Email(Document):
+            sender = StringField()
+            to = StringField()
+            subject = StringField()
+            body = StringField()
+            content_type = StringField()
+            attachments = ListField(EmbeddedDocumentField(Attachment))
+
+        Email.drop_collection()
+        email = Email(
+            sender="me",
+            to="you",
+            subject="From Russia with Love",
+            body="Hello!",
+            content_type="text/plain",
+        )
+        email.attachments = [
+            Attachment(name="file1.doc", content="ABC"),
+            Attachment(name="file2.doc", content="XYZ"),
+        ]
+        email.save()
+
+        obj = Email.objects.exclude("content_type").exclude("body").get()
+        assert obj.sender == "me"
+        assert obj.to == "you"
+        assert obj.subject == "From Russia with Love"
+        assert obj.body is None
+        assert obj.content_type is None
+
+        obj = Email.objects.only("sender", "to").exclude("body", "sender").get()
+        assert obj.sender is None
+        assert obj.to == "you"
+        assert obj.subject is None
+        assert obj.body is None
+        assert obj.content_type is None
+
+        obj = (
+            Email.objects.exclude("attachments.content")
+            .exclude("body")
+            .only("to", "attachments.name")
+            .get()
+        )
+        assert obj.attachments[0].name == "file1.doc"
+        assert obj.attachments[0].content is None
+        assert obj.sender is None
+        assert obj.to == "you"
+        assert obj.subject is None
+        assert obj.body is None
+        assert obj.content_type is None
+
+        Email.drop_collection()
+
+    def test_all_fields(self):
+        class Email(Document):
+            sender = StringField()
+            to = StringField()
+            subject = StringField()
+            body = StringField()
+            content_type = StringField()
+
+        Email.drop_collection()
+
+        email = Email(
+            sender="me",
+            to="you",
+            subject="From Russia with Love",
+            body="Hello!",
+            content_type="text/plain",
+        )
+        email.save()
+
+        obj = (
+            Email.objects.exclude("content_type", "body")
+            .only("to", "body")
+            .all_fields()
+            .get()
+        )
+        assert obj.sender == "me"
+        assert obj.to == "you"
+        assert obj.subject == "From Russia with Love"
+        assert obj.body == "Hello!"
+        assert obj.content_type == "text/plain"
+
+        Email.drop_collection()
+
+    def test_slicing_fields(self):
+        """Ensure that query slicing an array works.
+        """
+
+        class Numbers(Document):
+            n = ListField(IntField())
+
+        Numbers.drop_collection()
+
+        numbers = Numbers(n=[0, 1, 2, 3, 4, 5, -5, -4, -3, -2, -1])
+        numbers.save()
+
+        # first three
+        numbers = Numbers.objects.fields(slice__n=3).get()
+        assert numbers.n == [0, 1, 2]
+
+        # last three
+        numbers = Numbers.objects.fields(slice__n=-3).get()
+        assert numbers.n == [-3, -2, -1]
+
+        # skip 2, limit 3
+        numbers = Numbers.objects.fields(slice__n=[2, 3]).get()
+        assert numbers.n == [2, 3, 4]
+
+        # skip to fifth from last, limit 4
+        numbers = Numbers.objects.fields(slice__n=[-5, 4]).get()
+        assert numbers.n == [-5, -4, -3, -2]
+
+        # skip to fifth from last, limit 10
+        numbers = Numbers.objects.fields(slice__n=[-5, 10]).get()
+        assert numbers.n == [-5, -4, -3, -2, -1]
+
+        # skip to fifth from last, limit 10 dict method
+        numbers = Numbers.objects.fields(n={"$slice": [-5, 10]}).get()
+        assert numbers.n == [-5, -4, -3, -2, -1]
+
+    def test_slicing_nested_fields(self):
+        """Ensure that query slicing an embedded array works.
+        """
+
+        class EmbeddedNumber(EmbeddedDocument):
+            n = ListField(IntField())
+
+        class Numbers(Document):
+            embedded = EmbeddedDocumentField(EmbeddedNumber)
+
+        Numbers.drop_collection()
+
+        numbers = Numbers()
+        numbers.embedded = EmbeddedNumber(n=[0, 1, 2, 3, 4, 5, -5, -4, -3, -2, -1])
+        numbers.save()
+
+        # first three
+        numbers = Numbers.objects.fields(slice__embedded__n=3).get()
+        assert numbers.embedded.n == [0, 1, 2]
+
+        # last three
+        numbers = Numbers.objects.fields(slice__embedded__n=-3).get()
+        assert numbers.embedded.n == [-3, -2, -1]
+
+        # skip 2, limit 3
+        numbers = Numbers.objects.fields(slice__embedded__n=[2, 3]).get()
+        assert numbers.embedded.n == [2, 3, 4]
+
+        # skip to fifth from last, limit 4
+        numbers = Numbers.objects.fields(slice__embedded__n=[-5, 4]).get()
+        assert numbers.embedded.n == [-5, -4, -3, -2]
+
+        # skip to fifth from last, limit 10
+        numbers = Numbers.objects.fields(slice__embedded__n=[-5, 10]).get()
+        assert numbers.embedded.n == [-5, -4, -3, -2, -1]
+
+        # skip to fifth from last, limit 10 dict method
+        numbers = Numbers.objects.fields(embedded__n={"$slice": [-5, 10]}).get()
+        assert numbers.embedded.n == [-5, -4, -3, -2, -1]
+
+    def test_exclude_from_subclasses_docs(self):
+        class Base(Document):
+            username = StringField()
+
+            meta = {"allow_inheritance": True}
+
+        class Anon(Base):
+            anon = BooleanField()
+
+        class User(Base):
+            password = StringField()
+            wibble = StringField()
+
+        Base.drop_collection()
+        User(username="mongodb", password="secret").save()
+
+        user = Base.objects().exclude("password", "wibble").first()
+        assert user.password is None
+
+        with pytest.raises(LookUpError):
+            Base.objects.exclude("made_up")
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/queryset/test_geo.py

@@ -6,13 +6,10 @@ from mongoengine import *
 from tests.utils import MongoDBTestCase
 
 
-__all__ = ("GeoQueriesTest",)
+class TestGeoQueries(MongoDBTestCase):
-
-
-class GeoQueriesTest(MongoDBTestCase):
-
     def _create_event_data(self, point_field_class=GeoPointField):
         """Create some sample data re-used in many of the tests below."""
+
         class Event(Document):
             title = StringField()
             date = DateTimeField()
@@ -28,15 +25,18 @@ class GeoQueriesTest(MongoDBTestCase):
         event1 = Event.objects.create(
             title="Coltrane Motion @ Double Door",
             date=datetime.datetime.now() - datetime.timedelta(days=1),
-            location=[-87.677137, 41.909889])
+            location=[-87.677137, 41.909889],
+        )
         event2 = Event.objects.create(
             title="Coltrane Motion @ Bottom of the Hill",
             date=datetime.datetime.now() - datetime.timedelta(days=10),
-            location=[-122.4194155, 37.7749295])
+            location=[-122.4194155, 37.7749295],
+        )
         event3 = Event.objects.create(
             title="Coltrane Motion @ Empty Bottle",
             date=datetime.datetime.now(),
-            location=[-87.686638, 41.900474])
+            location=[-87.686638, 41.900474],
+        )
 
         return event1, event2, event3
 
@@ -48,14 +48,14 @@ class GeoQueriesTest(MongoDBTestCase):
         # note that "near" will show the san francisco event, too,
         # although it sorts to last.
         events = self.Event.objects(location__near=[-87.67892, 41.9120459])
-        self.assertEqual(events.count(), 3)
+        assert events.count() == 3
-        self.assertEqual(list(events), [event1, event3, event2])
+        assert list(events) == [event1, event3, event2]
 
         # ensure ordering is respected by "near"
         events = self.Event.objects(location__near=[-87.67892, 41.9120459])
         events = events.order_by("-date")
-        self.assertEqual(events.count(), 3)
+        assert events.count() == 3
-        self.assertEqual(list(events), [event3, event1, event2])
+        assert list(events) == [event3, event1, event2]
 
     def test_near_and_max_distance(self):
         """Ensure the "max_distance" operator works alongside the "near"
@@ -65,10 +65,9 @@ class GeoQueriesTest(MongoDBTestCase):
 
         # find events within 10 degrees of san francisco
         point = [-122.415579, 37.7566023]
-        events = self.Event.objects(location__near=point,
+        events = self.Event.objects(location__near=point, location__max_distance=10)
-                                    location__max_distance=10)
+        assert events.count() == 1
-        self.assertEqual(events.count(), 1)
+        assert events[0] == event2
-        self.assertEqual(events[0], event2)
 
     def test_near_and_min_distance(self):
         """Ensure the "min_distance" operator works alongside the "near"
@@ -78,9 +77,8 @@ class GeoQueriesTest(MongoDBTestCase):
 
         # find events at least 10 degrees away of san francisco
         point = [-122.415579, 37.7566023]
-        events = self.Event.objects(location__near=point,
+        events = self.Event.objects(location__near=point, location__min_distance=10)
-                                    location__min_distance=10)
+        assert events.count() == 2
-        self.assertEqual(events.count(), 2)
 
     def test_within_distance(self):
         """Make sure the "within_distance" operator works."""
@@ -88,34 +86,30 @@ class GeoQueriesTest(MongoDBTestCase):
 
         # find events within 5 degrees of pitchfork office, chicago
         point_and_distance = [[-87.67892, 41.9120459], 5]
-        events = self.Event.objects(
+        events = self.Event.objects(location__within_distance=point_and_distance)
-            location__within_distance=point_and_distance)
+        assert events.count() == 2
-        self.assertEqual(events.count(), 2)
         events = list(events)
-        self.assertNotIn(event2, events)
+        assert event2 not in events
-        self.assertIn(event1, events)
+        assert event1 in events
-        self.assertIn(event3, events)
+        assert event3 in events
 
         # find events within 10 degrees of san francisco
         point_and_distance = [[-122.415579, 37.7566023], 10]
-        events = self.Event.objects(
+        events = self.Event.objects(location__within_distance=point_and_distance)
-            location__within_distance=point_and_distance)
+        assert events.count() == 1
-        self.assertEqual(events.count(), 1)
+        assert events[0] == event2
-        self.assertEqual(events[0], event2)
 
         # find events within 1 degree of greenpoint, broolyn, nyc, ny
         point_and_distance = [[-73.9509714, 40.7237134], 1]
-        events = self.Event.objects(
+        events = self.Event.objects(location__within_distance=point_and_distance)
-            location__within_distance=point_and_distance)
+        assert events.count() == 0
-        self.assertEqual(events.count(), 0)
 
         # ensure ordering is respected by "within_distance"
         point_and_distance = [[-87.67892, 41.9120459], 10]
-        events = self.Event.objects(
+        events = self.Event.objects(location__within_distance=point_and_distance)
-            location__within_distance=point_and_distance)
         events = events.order_by("-date")
-        self.assertEqual(events.count(), 2)
+        assert events.count() == 2
-        self.assertEqual(events[0], event3)
+        assert events[0] == event3
 
     def test_within_box(self):
         """Ensure the "within_box" operator works."""
@@ -124,8 +118,8 @@ class GeoQueriesTest(MongoDBTestCase):
         # check that within_box works
         box = [(-125.0, 35.0), (-100.0, 40.0)]
         events = self.Event.objects(location__within_box=box)
-        self.assertEqual(events.count(), 1)
+        assert events.count() == 1
-        self.assertEqual(events[0].id, event2.id)
+        assert events[0].id == event2.id
 
     def test_within_polygon(self):
         """Ensure the "within_polygon" operator works."""
@@ -139,87 +133,78 @@ class GeoQueriesTest(MongoDBTestCase):
             (-87.656164, 41.898061),
         ]
         events = self.Event.objects(location__within_polygon=polygon)
-        self.assertEqual(events.count(), 1)
+        assert events.count() == 1
-        self.assertEqual(events[0].id, event1.id)
+        assert events[0].id == event1.id
 
         polygon2 = [
             (-1.742249, 54.033586),
             (-1.225891, 52.792797),
-            (-4.40094, 53.389881)
+            (-4.40094, 53.389881),
         ]
         events = self.Event.objects(location__within_polygon=polygon2)
-        self.assertEqual(events.count(), 0)
+        assert events.count() == 0
 
     def test_2dsphere_near(self):
         """Make sure the "near" operator works with a PointField, which
         corresponds to a 2dsphere index.
         """
-        event1, event2, event3 = self._create_event_data(
+        event1, event2, event3 = self._create_event_data(point_field_class=PointField)
-            point_field_class=PointField
-        )
 
         # find all events "near" pitchfork office, chicago.
         # note that "near" will show the san francisco event, too,
         # although it sorts to last.
         events = self.Event.objects(location__near=[-87.67892, 41.9120459])
-        self.assertEqual(events.count(), 3)
+        assert events.count() == 3
-        self.assertEqual(list(events), [event1, event3, event2])
+        assert list(events) == [event1, event3, event2]
 
         # ensure ordering is respected by "near"
         events = self.Event.objects(location__near=[-87.67892, 41.9120459])
         events = events.order_by("-date")
-        self.assertEqual(events.count(), 3)
+        assert events.count() == 3
-        self.assertEqual(list(events), [event3, event1, event2])
+        assert list(events) == [event3, event1, event2]
 
     def test_2dsphere_near_and_max_distance(self):
         """Ensure the "max_distance" operator works alongside the "near"
         operator with a 2dsphere index.
         """
-        event1, event2, event3 = self._create_event_data(
+        event1, event2, event3 = self._create_event_data(point_field_class=PointField)
-            point_field_class=PointField
-        )
 
         # find events within 10km of san francisco
         point = [-122.415579, 37.7566023]
-        events = self.Event.objects(location__near=point,
+        events = self.Event.objects(location__near=point, location__max_distance=10000)
-                                    location__max_distance=10000)
+        assert events.count() == 1
-        self.assertEqual(events.count(), 1)
+        assert events[0] == event2
-        self.assertEqual(events[0], event2)
 
         # find events within 1km of greenpoint, broolyn, nyc, ny
-        events = self.Event.objects(location__near=[-73.9509714, 40.7237134],
+        events = self.Event.objects(
-                                    location__max_distance=1000)
+            location__near=[-73.9509714, 40.7237134], location__max_distance=1000
-        self.assertEqual(events.count(), 0)
+        )
+        assert events.count() == 0
 
         # ensure ordering is respected by "near"
         events = self.Event.objects(
-            location__near=[-87.67892, 41.9120459],
+            location__near=[-87.67892, 41.9120459], location__max_distance=10000
-            location__max_distance=10000
         ).order_by("-date")
-        self.assertEqual(events.count(), 2)
+        assert events.count() == 2
-        self.assertEqual(events[0], event3)
+        assert events[0] == event3
 
     def test_2dsphere_geo_within_box(self):
         """Ensure the "geo_within_box" operator works with a 2dsphere
         index.
         """
-        event1, event2, event3 = self._create_event_data(
+        event1, event2, event3 = self._create_event_data(point_field_class=PointField)
-            point_field_class=PointField
-        )
 
         # check that within_box works
         box = [(-125.0, 35.0), (-100.0, 40.0)]
         events = self.Event.objects(location__geo_within_box=box)
-        self.assertEqual(events.count(), 1)
+        assert events.count() == 1
-        self.assertEqual(events[0].id, event2.id)
+        assert events[0].id == event2.id
 
     def test_2dsphere_geo_within_polygon(self):
         """Ensure the "geo_within_polygon" operator works with a
         2dsphere index.
         """
-        event1, event2, event3 = self._create_event_data(
+        event1, event2, event3 = self._create_event_data(point_field_class=PointField)
-            point_field_class=PointField
-        )
 
         polygon = [
             (-87.694445, 41.912114),
@@ -229,64 +214,59 @@ class GeoQueriesTest(MongoDBTestCase):
             (-87.656164, 41.898061),
         ]
         events = self.Event.objects(location__geo_within_polygon=polygon)
-        self.assertEqual(events.count(), 1)
+        assert events.count() == 1
-        self.assertEqual(events[0].id, event1.id)
+        assert events[0].id == event1.id
 
         polygon2 = [
             (-1.742249, 54.033586),
             (-1.225891, 52.792797),
-            (-4.40094, 53.389881)
+            (-4.40094, 53.389881),
         ]
         events = self.Event.objects(location__geo_within_polygon=polygon2)
-        self.assertEqual(events.count(), 0)
+        assert events.count() == 0
 
     def test_2dsphere_near_and_min_max_distance(self):
         """Ensure "min_distace" and "max_distance" operators work well
         together with the "near" operator in a 2dsphere index.
         """
-        event1, event2, event3 = self._create_event_data(
+        event1, event2, event3 = self._create_event_data(point_field_class=PointField)
-            point_field_class=PointField
-        )
 
         # ensure min_distance and max_distance combine well
         events = self.Event.objects(
             location__near=[-87.67892, 41.9120459],
             location__min_distance=1000,
-            location__max_distance=10000
+            location__max_distance=10000,
         ).order_by("-date")
-        self.assertEqual(events.count(), 1)
+        assert events.count() == 1
-        self.assertEqual(events[0], event3)
+        assert events[0] == event3
 
         # ensure ordering is respected by "near" with "min_distance"
         events = self.Event.objects(
-            location__near=[-87.67892, 41.9120459],
+            location__near=[-87.67892, 41.9120459], location__min_distance=10000
-            location__min_distance=10000
         ).order_by("-date")
-        self.assertEqual(events.count(), 1)
+        assert events.count() == 1
-        self.assertEqual(events[0], event2)
+        assert events[0] == event2
 
     def test_2dsphere_geo_within_center(self):
         """Make sure the "geo_within_center" operator works with a
         2dsphere index.
         """
-        event1, event2, event3 = self._create_event_data(
+        event1, event2, event3 = self._create_event_data(point_field_class=PointField)
-            point_field_class=PointField
-        )
 
         # find events within 5 degrees of pitchfork office, chicago
         point_and_distance = [[-87.67892, 41.9120459], 2]
-        events = self.Event.objects(
+        events = self.Event.objects(location__geo_within_center=point_and_distance)
-            location__geo_within_center=point_and_distance)
+        assert events.count() == 2
-        self.assertEqual(events.count(), 2)
         events = list(events)
-        self.assertNotIn(event2, events)
+        assert event2 not in events
-        self.assertIn(event1, events)
+        assert event1 in events
-        self.assertIn(event3, events)
+        assert event3 in events
 
     def _test_embedded(self, point_field_class):
         """Helper test method ensuring given point field class works
         well in an embedded document.
         """
+
         class Venue(EmbeddedDocument):
             location = point_field_class()
             name = StringField()
@@ -300,19 +280,18 @@ class GeoQueriesTest(MongoDBTestCase):
         venue1 = Venue(name="The Rock", location=[-87.677137, 41.909889])
         venue2 = Venue(name="The Bridge", location=[-122.4194155, 37.7749295])
 
-        event1 = Event(title="Coltrane Motion @ Double Door",
+        event1 = Event(title="Coltrane Motion @ Double Door", venue=venue1).save()
-                       venue=venue1).save()
+        event2 = Event(
-        event2 = Event(title="Coltrane Motion @ Bottom of the Hill",
+            title="Coltrane Motion @ Bottom of the Hill", venue=venue2
-                       venue=venue2).save()
+        ).save()
-        event3 = Event(title="Coltrane Motion @ Empty Bottle",
+        event3 = Event(title="Coltrane Motion @ Empty Bottle", venue=venue1).save()
-                       venue=venue1).save()
 
         # find all events "near" pitchfork office, chicago.
         # note that "near" will show the san francisco event, too,
         # although it sorts to last.
         events = Event.objects(venue__location__near=[-87.67892, 41.9120459])
-        self.assertEqual(events.count(), 3)
+        assert events.count() == 3
-        self.assertEqual(list(events), [event1, event3, event2])
+        assert list(events) == [event1, event3, event2]
 
     def test_geo_spatial_embedded(self):
         """Make sure GeoPointField works properly in an embedded document."""
@@ -324,6 +303,7 @@ class GeoQueriesTest(MongoDBTestCase):
 
     def test_spherical_geospatial_operators(self):
         """Ensure that spherical geospatial queries are working."""
+
         class Point(Document):
             location = GeoPointField()
 
@@ -339,58 +319,55 @@ class GeoQueriesTest(MongoDBTestCase):
         # Finds both points because they are within 60 km of the reference
         # point equidistant between them.
         points = Point.objects(location__near_sphere=[-122, 37.5])
-        self.assertEqual(points.count(), 2)
+        assert points.count() == 2
 
         # Same behavior for _within_spherical_distance
         points = Point.objects(
-            location__within_spherical_distance=[
+            location__within_spherical_distance=[[-122, 37.5], 60 / earth_radius]
-                [-122, 37.5],
-                60 / earth_radius
-            ]
         )
-        self.assertEqual(points.count(), 2)
+        assert points.count() == 2
 
-        points = Point.objects(location__near_sphere=[-122, 37.5],
+        points = Point.objects(
-                               location__max_distance=60 / earth_radius)
+            location__near_sphere=[-122, 37.5], location__max_distance=60 / earth_radius
-        self.assertEqual(points.count(), 2)
+        )
+        assert points.count() == 2
 
         # Test query works with max_distance, being farer from one point
-        points = Point.objects(location__near_sphere=[-122, 37.8],
+        points = Point.objects(
-                               location__max_distance=60 / earth_radius)
+            location__near_sphere=[-122, 37.8], location__max_distance=60 / earth_radius
+        )
         close_point = points.first()
-        self.assertEqual(points.count(), 1)
+        assert points.count() == 1
 
         # Test query works with min_distance, being farer from one point
-        points = Point.objects(location__near_sphere=[-122, 37.8],
+        points = Point.objects(
-                               location__min_distance=60 / earth_radius)
+            location__near_sphere=[-122, 37.8], location__min_distance=60 / earth_radius
-        self.assertEqual(points.count(), 1)
+        )
+        assert points.count() == 1
         far_point = points.first()
-        self.assertNotEqual(close_point, far_point)
+        assert close_point != far_point
 
         # Finds both points, but orders the north point first because it's
         # closer to the reference point to the north.
         points = Point.objects(location__near_sphere=[-122, 38.5])
-        self.assertEqual(points.count(), 2)
+        assert points.count() == 2
-        self.assertEqual(points[0].id, north_point.id)
+        assert points[0].id == north_point.id
-        self.assertEqual(points[1].id, south_point.id)
+        assert points[1].id == south_point.id
 
         # Finds both points, but orders the south point first because it's
         # closer to the reference point to the south.
         points = Point.objects(location__near_sphere=[-122, 36.5])
-        self.assertEqual(points.count(), 2)
+        assert points.count() == 2
-        self.assertEqual(points[0].id, south_point.id)
+        assert points[0].id == south_point.id
-        self.assertEqual(points[1].id, north_point.id)
+        assert points[1].id == north_point.id
 
         # Finds only one point because only the first point is within 60km of
         # the reference point to the south.
         points = Point.objects(
-            location__within_spherical_distance=[
+            location__within_spherical_distance=[[-122, 36.5], 60 / earth_radius]
-                [-122, 36.5],
-                60 / earth_radius
-            ]
         )
-        self.assertEqual(points.count(), 1)
+        assert points.count() == 1
-        self.assertEqual(points[0].id, south_point.id)
+        assert points[0].id == south_point.id
 
     def test_linestring(self):
         class Road(Document):
@@ -404,48 +381,51 @@ class GeoQueriesTest(MongoDBTestCase):
         # near
         point = {"type": "Point", "coordinates": [40, 5]}
         roads = Road.objects.filter(line__near=point["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__near=point).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__near={"$geometry": point}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         # Within
-        polygon = {"type": "Polygon",
+        polygon = {
-                   "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]]}
+            "type": "Polygon",
+            "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]],
+        }
         roads = Road.objects.filter(line__geo_within=polygon["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__geo_within=polygon).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__geo_within={"$geometry": polygon}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         # Intersects
-        line = {"type": "LineString",
+        line = {"type": "LineString", "coordinates": [[40, 5], [40, 6]]}
-                "coordinates": [[40, 5], [40, 6]]}
         roads = Road.objects.filter(line__geo_intersects=line["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__geo_intersects=line).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__geo_intersects={"$geometry": line}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
-        polygon = {"type": "Polygon",
+        polygon = {
-                   "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]]}
+            "type": "Polygon",
+            "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]],
+        }
         roads = Road.objects.filter(line__geo_intersects=polygon["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__geo_intersects=polygon).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(line__geo_intersects={"$geometry": polygon}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
     def test_polygon(self):
         class Road(Document):
@@ -459,66 +439,66 @@ class GeoQueriesTest(MongoDBTestCase):
         # near
         point = {"type": "Point", "coordinates": [40, 5]}
         roads = Road.objects.filter(poly__near=point["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__near=point).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__near={"$geometry": point}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         # Within
-        polygon = {"type": "Polygon",
+        polygon = {
-                   "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]]}
+            "type": "Polygon",
+            "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]],
+        }
         roads = Road.objects.filter(poly__geo_within=polygon["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__geo_within=polygon).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__geo_within={"$geometry": polygon}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         # Intersects
-        line = {"type": "LineString",
+        line = {"type": "LineString", "coordinates": [[40, 5], [41, 6]]}
-                "coordinates": [[40, 5], [41, 6]]}
         roads = Road.objects.filter(poly__geo_intersects=line["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__geo_intersects=line).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__geo_intersects={"$geometry": line}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
-        polygon = {"type": "Polygon",
+        polygon = {
-                   "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]]}
+            "type": "Polygon",
+            "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]],
+        }
         roads = Road.objects.filter(poly__geo_intersects=polygon["coordinates"]).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__geo_intersects=polygon).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
         roads = Road.objects.filter(poly__geo_intersects={"$geometry": polygon}).count()
-        self.assertEqual(1, roads)
+        assert 1 == roads
 
     def test_aspymongo_with_only(self):
         """Ensure as_pymongo works with only"""
+
         class Place(Document):
             location = PointField()
 
         Place.drop_collection()
         p = Place(location=[24.946861267089844, 60.16311983618494])
         p.save()
-        qs = Place.objects().only('location')
+        qs = Place.objects().only("location")
-        self.assertDictEqual(
+        assert qs.as_pymongo()[0]["location"] == {
-            qs.as_pymongo()[0]['location'],
+            u"type": u"Point",
-            {u'type': u'Point',
+            u"coordinates": [24.946861267089844, 60.16311983618494],
-             u'coordinates': [
+        }
-                24.946861267089844,
-                60.16311983618494]
-            }
-        )
 
     def test_2dsphere_point_sets_correctly(self):
         class Location(Document):
@@ -528,11 +508,11 @@ class GeoQueriesTest(MongoDBTestCase):
 
         Location(loc=[1, 2]).save()
         loc = Location.objects.as_pymongo()[0]
-        self.assertEqual(loc["loc"], {"type": "Point", "coordinates": [1, 2]})
+        assert loc["loc"] == {"type": "Point", "coordinates": [1, 2]}
 
         Location.objects.update(set__loc=[2, 1])
         loc = Location.objects.as_pymongo()[0]
-        self.assertEqual(loc["loc"], {"type": "Point", "coordinates": [2, 1]})
+        assert loc["loc"] == {"type": "Point", "coordinates": [2, 1]}
 
     def test_2dsphere_linestring_sets_correctly(self):
         class Location(Document):
@@ -542,11 +522,11 @@ class GeoQueriesTest(MongoDBTestCase):
 
         Location(line=[[1, 2], [2, 2]]).save()
         loc = Location.objects.as_pymongo()[0]
-        self.assertEqual(loc["line"], {"type": "LineString", "coordinates": [[1, 2], [2, 2]]})
+        assert loc["line"] == {"type": "LineString", "coordinates": [[1, 2], [2, 2]]}
 
         Location.objects.update(set__line=[[2, 1], [1, 2]])
         loc = Location.objects.as_pymongo()[0]
-        self.assertEqual(loc["line"], {"type": "LineString", "coordinates": [[2, 1], [1, 2]]})
+        assert loc["line"] == {"type": "LineString", "coordinates": [[2, 1], [1, 2]]}
 
     def test_geojson_PolygonField(self):
         class Location(Document):
@@ -556,12 +536,18 @@ class GeoQueriesTest(MongoDBTestCase):
 
         Location(poly=[[[40, 5], [40, 6], [41, 6], [40, 5]]]).save()
         loc = Location.objects.as_pymongo()[0]
-        self.assertEqual(loc["poly"], {"type": "Polygon", "coordinates": [[[40, 5], [40, 6], [41, 6], [40, 5]]]})
+        assert loc["poly"] == {
+            "type": "Polygon",
+            "coordinates": [[[40, 5], [40, 6], [41, 6], [40, 5]]],
+        }
 
         Location.objects.update(set__poly=[[[40, 4], [40, 6], [41, 6], [40, 4]]])
         loc = Location.objects.as_pymongo()[0]
-        self.assertEqual(loc["poly"], {"type": "Polygon", "coordinates": [[[40, 4], [40, 6], [41, 6], [40, 4]]]})
+        assert loc["poly"] == {
+            "type": "Polygon",
+            "coordinates": [[[40, 4], [40, 6], [41, 6], [40, 4]]],
+        }
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/queryset/test_modify.py

@@ -1,8 +1,6 @@
 import unittest
 
-from mongoengine import connect, Document, IntField, StringField, ListField
+from mongoengine import Document, IntField, ListField, StringField, connect
-
-__all__ = ("FindAndModifyTest",)
 
 
 class Doc(Document):
@@ -10,21 +8,20 @@ class Doc(Document):
     value = IntField()
 
 
-class FindAndModifyTest(unittest.TestCase):
+class TestFindAndModify(unittest.TestCase):
-
     def setUp(self):
         connect(db="mongoenginetest")
         Doc.drop_collection()
 
     def assertDbEqual(self, docs):
-        self.assertEqual(list(Doc._collection.find().sort("id")), docs)
+        assert list(Doc._collection.find().sort("id")) == docs
 
     def test_modify(self):
         Doc(id=0, value=0).save()
         doc = Doc(id=1, value=1).save()
 
         old_doc = Doc.objects(id=1).modify(set__value=-1)
-        self.assertEqual(old_doc.to_json(), doc.to_json())
+        assert old_doc.to_json() == doc.to_json()
         self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
 
     def test_modify_with_new(self):
@@ -33,18 +30,18 @@ class FindAndModifyTest(unittest.TestCase):
 
         new_doc = Doc.objects(id=1).modify(set__value=-1, new=True)
         doc.value = -1
-        self.assertEqual(new_doc.to_json(), doc.to_json())
+        assert new_doc.to_json() == doc.to_json()
         self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
 
     def test_modify_not_existing(self):
         Doc(id=0, value=0).save()
-        self.assertEqual(Doc.objects(id=1).modify(set__value=-1), None)
+        assert Doc.objects(id=1).modify(set__value=-1) is None
         self.assertDbEqual([{"_id": 0, "value": 0}])
 
     def test_modify_with_upsert(self):
         Doc(id=0, value=0).save()
         old_doc = Doc.objects(id=1).modify(set__value=1, upsert=True)
-        self.assertEqual(old_doc, None)
+        assert old_doc is None
         self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": 1}])
 
     def test_modify_with_upsert_existing(self):
@@ -52,13 +49,13 @@ class FindAndModifyTest(unittest.TestCase):
         doc = Doc(id=1, value=1).save()
 
         old_doc = Doc.objects(id=1).modify(set__value=-1, upsert=True)
-        self.assertEqual(old_doc.to_json(), doc.to_json())
+        assert old_doc.to_json() == doc.to_json()
         self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
 
     def test_modify_with_upsert_with_new(self):
         Doc(id=0, value=0).save()
         new_doc = Doc.objects(id=1).modify(upsert=True, new=True, set__value=1)
-        self.assertEqual(new_doc.to_mongo(), {"_id": 1, "value": 1})
+        assert new_doc.to_mongo() == {"_id": 1, "value": 1}
         self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": 1}])
 
     def test_modify_with_remove(self):
@@ -66,12 +63,12 @@ class FindAndModifyTest(unittest.TestCase):
         doc = Doc(id=1, value=1).save()
 
         old_doc = Doc.objects(id=1).modify(remove=True)
-        self.assertEqual(old_doc.to_json(), doc.to_json())
+        assert old_doc.to_json() == doc.to_json()
         self.assertDbEqual([{"_id": 0, "value": 0}])
 
     def test_find_and_modify_with_remove_not_existing(self):
         Doc(id=0, value=0).save()
-        self.assertEqual(Doc.objects(id=1).modify(remove=True), None)
+        assert Doc.objects(id=1).modify(remove=True) is None
         self.assertDbEqual([{"_id": 0, "value": 0}])
 
     def test_modify_with_order_by(self):
@@ -81,17 +78,22 @@ class FindAndModifyTest(unittest.TestCase):
         doc = Doc(id=3, value=0).save()
 
         old_doc = Doc.objects().order_by("-id").modify(set__value=-1)
-        self.assertEqual(old_doc.to_json(), doc.to_json())
+        assert old_doc.to_json() == doc.to_json()
-        self.assertDbEqual([
+        self.assertDbEqual(
-            {"_id": 0, "value": 3}, {"_id": 1, "value": 2},
+            [
-            {"_id": 2, "value": 1}, {"_id": 3, "value": -1}])
+                {"_id": 0, "value": 3},
+                {"_id": 1, "value": 2},
+                {"_id": 2, "value": 1},
+                {"_id": 3, "value": -1},
+            ]
+        )
 
     def test_modify_with_fields(self):
         Doc(id=0, value=0).save()
         Doc(id=1, value=1).save()
 
         old_doc = Doc.objects(id=1).only("id").modify(set__value=-1)
-        self.assertEqual(old_doc.to_mongo(), {"_id": 1})
+        assert old_doc.to_mongo() == {"_id": 1}
         self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
 
     def test_modify_with_push(self):
@@ -103,27 +105,25 @@ class FindAndModifyTest(unittest.TestCase):
         blog = BlogPost.objects.create()
 
         # Push a new tag via modify with new=False (default).
-        BlogPost(id=blog.id).modify(push__tags='code')
+        BlogPost(id=blog.id).modify(push__tags="code")
-        self.assertEqual(blog.tags, [])
+        assert blog.tags == []
         blog.reload()
-        self.assertEqual(blog.tags, ['code'])
+        assert blog.tags == ["code"]
 
         # Push a new tag via modify with new=True.
-        blog = BlogPost.objects(id=blog.id).modify(push__tags='java', new=True)
+        blog = BlogPost.objects(id=blog.id).modify(push__tags="java", new=True)
-        self.assertEqual(blog.tags, ['code', 'java'])
+        assert blog.tags == ["code", "java"]
 
         # Push a new tag with a positional argument.
-        blog = BlogPost.objects(id=blog.id).modify(
+        blog = BlogPost.objects(id=blog.id).modify(push__tags__0="python", new=True)
-            push__tags__0='python',
+        assert blog.tags == ["python", "code", "java"]
-            new=True)
-        self.assertEqual(blog.tags, ['python', 'code', 'java'])
 
         # Push multiple new tags with a positional argument.
         blog = BlogPost.objects(id=blog.id).modify(
-            push__tags__1=['go', 'rust'],
+            push__tags__1=["go", "rust"], new=True
-            new=True)
+        )
-        self.assertEqual(blog.tags, ['python', 'go', 'rust', 'code', 'java'])
+        assert blog.tags == ["python", "go", "rust", "code", "java"]
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

tests/queryset/test_pickable.py

@@ -1,10 +1,9 @@
 import pickle
 import unittest
-from pymongo.mongo_client import MongoClient
-from mongoengine import Document, StringField, IntField
-from mongoengine.connection import connect
 
-__author__ = 'stas'
+from mongoengine import Document, IntField, StringField
+from mongoengine.connection import connect
+from tests.utils import MongoDBTestCase
 
 
 class Person(Document):
@@ -12,22 +11,15 @@ class Person(Document):
     age = IntField()
 
 
-class TestQuerysetPickable(unittest.TestCase):
+class TestQuerysetPickable(MongoDBTestCase):
     """
     Test for adding pickling support for QuerySet instances
     See issue https://github.com/MongoEngine/mongoengine/issues/442
     """
+
     def setUp(self):
         super(TestQuerysetPickable, self).setUp()
-
+        self.john = Person.objects.create(name="John", age=21)
-        connection = connect(db="test")  # type: pymongo.mongo_client.MongoClient
-
-        connection.drop_database("test")
-
-        self.john = Person.objects.create(
-            name="John",
-            age=21
-        )
 
     def test_picke_simple_qs(self):
 
@@ -45,35 +37,23 @@ class TestQuerysetPickable(unittest.TestCase):
 
         loadedQs = self._get_loaded(qs)
 
-        self.assertEqual(qs.count(), loadedQs.count())
+        assert qs.count() == loadedQs.count()
 
         # can update loadedQs
         loadedQs.update(age=23)
 
         # check
-        self.assertEqual(Person.objects.first().age, 23)
+        assert Person.objects.first().age == 23
 
     def test_pickle_support_filtration(self):
-        Person.objects.create(
+        Person.objects.create(name="Alice", age=22)
-            name="Alice",
-            age=22
-        )
 
-        Person.objects.create(
+        Person.objects.create(name="Bob", age=23)
-            name="Bob",
-            age=23
-        )
 
         qs = Person.objects.filter(age__gte=22)
-        self.assertEqual(qs.count(), 2)
+        assert qs.count() == 2
 
         loaded = self._get_loaded(qs)
 
-        self.assertEqual(loaded.count(), 2)
+        assert loaded.count() == 2
-        self.assertEqual(loaded.filter(name="Bob").first().age, 23)
+        assert loaded.filter(name="Bob").first().age == 23
-
-
-
-
-
-

tests/queryset/test_queryset_aggregation.py

@@ -0,0 +1,255 @@
+# -*- coding: utf-8 -*-
+
+import unittest
+import warnings
+
+from pymongo.read_preferences import ReadPreference
+
+from mongoengine import *
+from tests.utils import MongoDBTestCase
+
+
+class TestQuerysetAggregate(MongoDBTestCase):
+    def test_read_preference_aggregation_framework(self):
+        class Bar(Document):
+            txt = StringField()
+
+            meta = {"indexes": ["txt"]}
+
+        # Aggregates with read_preference
+        pipeline = []
+        bars = Bar.objects.read_preference(
+            ReadPreference.SECONDARY_PREFERRED
+        ).aggregate(pipeline)
+        assert (
+            bars._CommandCursor__collection.read_preference
+            == ReadPreference.SECONDARY_PREFERRED
+        )
+
+    def test_queryset_aggregation_framework(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects(age__lte=22).aggregate(pipeline)
+
+        assert list(data) == [
+            {"_id": p1.pk, "name": "ISABELLA LUANNA"},
+            {"_id": p2.pk, "name": "WILSON JUNIOR"},
+        ]
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects(age__lte=22).order_by("-name").aggregate(pipeline)
+
+        assert list(data) == [
+            {"_id": p2.pk, "name": "WILSON JUNIOR"},
+            {"_id": p1.pk, "name": "ISABELLA LUANNA"},
+        ]
+
+        pipeline = [
+            {"$group": {"_id": None, "total": {"$sum": 1}, "avg": {"$avg": "$age"}}}
+        ]
+        data = (
+            Person.objects(age__gte=17, age__lte=40)
+            .order_by("-age")
+            .aggregate(pipeline)
+        )
+        assert list(data) == [{"_id": None, "avg": 29, "total": 2}]
+
+        pipeline = [{"$match": {"name": "Isabella Luanna"}}]
+        data = Person.objects().aggregate(pipeline)
+        assert list(data) == [{u"_id": p1.pk, u"age": 16, u"name": u"Isabella Luanna"}]
+
+    def test_queryset_aggregation_with_skip(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects.skip(1).aggregate(pipeline)
+
+        assert list(data) == [
+            {"_id": p2.pk, "name": "WILSON JUNIOR"},
+            {"_id": p3.pk, "name": "SANDRA MARA"},
+        ]
+
+    def test_queryset_aggregation_with_limit(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects.limit(1).aggregate(pipeline)
+
+        assert list(data) == [{"_id": p1.pk, "name": "ISABELLA LUANNA"}]
+
+    def test_queryset_aggregation_with_sort(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects.order_by("name").aggregate(pipeline)
+
+        assert list(data) == [
+            {"_id": p1.pk, "name": "ISABELLA LUANNA"},
+            {"_id": p3.pk, "name": "SANDRA MARA"},
+            {"_id": p2.pk, "name": "WILSON JUNIOR"},
+        ]
+
+    def test_queryset_aggregation_with_skip_with_limit(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = list(Person.objects.skip(1).limit(1).aggregate(pipeline))
+
+        assert list(data) == [{"_id": p2.pk, "name": "WILSON JUNIOR"}]
+
+        # Make sure limit/skip chaining order has no impact
+        data2 = Person.objects.limit(1).skip(1).aggregate(pipeline)
+
+        assert data == list(data2)
+
+    def test_queryset_aggregation_with_sort_with_limit(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects.order_by("name").limit(2).aggregate(pipeline)
+
+        assert list(data) == [
+            {"_id": p1.pk, "name": "ISABELLA LUANNA"},
+            {"_id": p3.pk, "name": "SANDRA MARA"},
+        ]
+
+        # Verify adding limit/skip steps works as expected
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}, {"$limit": 1}]
+        data = Person.objects.order_by("name").limit(2).aggregate(pipeline)
+
+        assert list(data) == [{"_id": p1.pk, "name": "ISABELLA LUANNA"}]
+
+        pipeline = [
+            {"$project": {"name": {"$toUpper": "$name"}}},
+            {"$skip": 1},
+            {"$limit": 1},
+        ]
+        data = Person.objects.order_by("name").limit(2).aggregate(pipeline)
+
+        assert list(data) == [{"_id": p3.pk, "name": "SANDRA MARA"}]
+
+    def test_queryset_aggregation_with_sort_with_skip(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects.order_by("name").skip(2).aggregate(pipeline)
+
+        assert list(data) == [{"_id": p2.pk, "name": "WILSON JUNIOR"}]
+
+    def test_queryset_aggregation_with_sort_with_skip_with_limit(self):
+        class Person(Document):
+            name = StringField()
+            age = IntField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna", age=16)
+        p2 = Person(name="Wilson Junior", age=21)
+        p3 = Person(name="Sandra Mara", age=37)
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+        data = Person.objects.order_by("name").skip(1).limit(1).aggregate(pipeline)
+
+        assert list(data) == [{"_id": p3.pk, "name": "SANDRA MARA"}]
+
+    def test_queryset_aggregation_deprecated_interface(self):
+        class Person(Document):
+            name = StringField()
+
+        Person.drop_collection()
+
+        p1 = Person(name="Isabella Luanna")
+        p2 = Person(name="Wilson Junior")
+        p3 = Person(name="Sandra Mara")
+        Person.objects.insert([p1, p2, p3])
+
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}]
+
+        # Make sure a warning is emitted
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", DeprecationWarning)
+            with self.assertRaises(DeprecationWarning):
+                Person.objects.order_by("name").limit(2).aggregate(*pipeline)
+
+        # Make sure old interface works as expected with a 1-step pipeline
+        data = Person.objects.order_by("name").limit(2).aggregate(*pipeline)
+
+        assert list(data) == [
+            {"_id": p1.pk, "name": "ISABELLA LUANNA"},
+            {"_id": p3.pk, "name": "SANDRA MARA"},
+        ]
+
+        # Make sure old interface works as expected with a 2-steps pipeline
+        pipeline = [{"$project": {"name": {"$toUpper": "$name"}}}, {"$limit": 1}]
+        data = Person.objects.order_by("name").limit(2).aggregate(*pipeline)
+
+        assert list(data) == [{"_id": p1.pk, "name": "ISABELLA LUANNA"}]
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/queryset/test_transform.py

@@ -0,0 +1,374 @@
+import unittest
+
+from bson.son import SON
+import pytest
+
+from mongoengine import *
+from mongoengine.queryset import Q, transform
+
+
+class TestTransform(unittest.TestCase):
+    def setUp(self):
+        connect(db="mongoenginetest")
+
+    def test_transform_query(self):
+        """Ensure that the _transform_query function operates correctly.
+        """
+        assert transform.query(name="test", age=30) == {"name": "test", "age": 30}
+        assert transform.query(age__lt=30) == {"age": {"$lt": 30}}
+        assert transform.query(age__gt=20, age__lt=50) == {
+            "age": {"$gt": 20, "$lt": 50}
+        }
+        assert transform.query(age=20, age__gt=50) == {
+            "$and": [{"age": {"$gt": 50}}, {"age": 20}]
+        }
+        assert transform.query(friend__age__gte=30) == {"friend.age": {"$gte": 30}}
+        assert transform.query(name__exists=True) == {"name": {"$exists": True}}
+        assert transform.query(name=["Mark"], __raw__={"name": {"$in": "Tom"}}) == {
+            "$and": [{"name": ["Mark"]}, {"name": {"$in": "Tom"}}]
+        }
+        assert transform.query(name__in=["Tom"], __raw__={"name": "Mark"}) == {
+            "$and": [{"name": {"$in": ["Tom"]}}, {"name": "Mark"}]
+        }
+
+    def test_transform_update(self):
+        class LisDoc(Document):
+            foo = ListField(StringField())
+
+        class DicDoc(Document):
+            dictField = DictField()
+
+        class Doc(Document):
+            pass
+
+        LisDoc.drop_collection()
+        DicDoc.drop_collection()
+        Doc.drop_collection()
+
+        DicDoc().save()
+        doc = Doc().save()
+
+        for k, v in (
+            ("set", "$set"),
+            ("set_on_insert", "$setOnInsert"),
+            ("push", "$push"),
+        ):
+            update = transform.update(DicDoc, **{"%s__dictField__test" % k: doc})
+            assert isinstance(update[v]["dictField.test"], dict)
+
+        # Update special cases
+        update = transform.update(DicDoc, unset__dictField__test=doc)
+        assert update["$unset"]["dictField.test"] == 1
+
+        update = transform.update(DicDoc, pull__dictField__test=doc)
+        assert isinstance(update["$pull"]["dictField"]["test"], dict)
+
+        update = transform.update(LisDoc, pull__foo__in=["a"])
+        assert update == {"$pull": {"foo": {"$in": ["a"]}}}
+
+    def test_transform_update_push(self):
+        """Ensure the differences in behvaior between 'push' and 'push_all'"""
+
+        class BlogPost(Document):
+            tags = ListField(StringField())
+
+        update = transform.update(BlogPost, push__tags=["mongo", "db"])
+        assert update == {"$push": {"tags": ["mongo", "db"]}}
+
+        update = transform.update(BlogPost, push_all__tags=["mongo", "db"])
+        assert update == {"$push": {"tags": {"$each": ["mongo", "db"]}}}
+
+    def test_transform_update_no_operator_default_to_set(self):
+        """Ensure the differences in behvaior between 'push' and 'push_all'"""
+
+        class BlogPost(Document):
+            tags = ListField(StringField())
+
+        update = transform.update(BlogPost, tags=["mongo", "db"])
+        assert update == {"$set": {"tags": ["mongo", "db"]}}
+
+    def test_query_field_name(self):
+        """Ensure that the correct field name is used when querying.
+        """
+
+        class Comment(EmbeddedDocument):
+            content = StringField(db_field="commentContent")
+
+        class BlogPost(Document):
+            title = StringField(db_field="postTitle")
+            comments = ListField(
+                EmbeddedDocumentField(Comment), db_field="postComments"
+            )
+
+        BlogPost.drop_collection()
+
+        data = {"title": "Post 1", "comments": [Comment(content="test")]}
+        post = BlogPost(**data)
+        post.save()
+
+        assert "postTitle" in BlogPost.objects(title=data["title"])._query
+        assert not ("title" in BlogPost.objects(title=data["title"])._query)
+        assert BlogPost.objects(title=data["title"]).count() == 1
+
+        assert "_id" in BlogPost.objects(pk=post.id)._query
+        assert BlogPost.objects(pk=post.id).count() == 1
+
+        assert (
+            "postComments.commentContent"
+            in BlogPost.objects(comments__content="test")._query
+        )
+        assert BlogPost.objects(comments__content="test").count() == 1
+
+        BlogPost.drop_collection()
+
+    def test_query_pk_field_name(self):
+        """Ensure that the correct "primary key" field name is used when
+        querying
+        """
+
+        class BlogPost(Document):
+            title = StringField(primary_key=True, db_field="postTitle")
+
+        BlogPost.drop_collection()
+
+        data = {"title": "Post 1"}
+        post = BlogPost(**data)
+        post.save()
+
+        assert "_id" in BlogPost.objects(pk=data["title"])._query
+        assert "_id" in BlogPost.objects(title=data["title"])._query
+        assert BlogPost.objects(pk=data["title"]).count() == 1
+
+        BlogPost.drop_collection()
+
+    def test_chaining(self):
+        class A(Document):
+            pass
+
+        class B(Document):
+            a = ReferenceField(A)
+
+        A.drop_collection()
+        B.drop_collection()
+
+        a1 = A().save()
+        a2 = A().save()
+
+        B(a=a1).save()
+
+        # Works
+        q1 = B.objects.filter(a__in=[a1, a2], a=a1)._query
+
+        # Doesn't work
+        q2 = B.objects.filter(a__in=[a1, a2])
+        q2 = q2.filter(a=a1)._query
+
+        assert q1 == q2
+
+    def test_raw_query_and_Q_objects(self):
+        """
+        Test raw plays nicely
+        """
+
+        class Foo(Document):
+            name = StringField()
+            a = StringField()
+            b = StringField()
+            c = StringField()
+
+            meta = {"allow_inheritance": False}
+
+        query = Foo.objects(__raw__={"$nor": [{"name": "bar"}]})._query
+        assert query == {"$nor": [{"name": "bar"}]}
+
+        q1 = {"$or": [{"a": 1}, {"b": 1}]}
+        query = Foo.objects(Q(__raw__=q1) & Q(c=1))._query
+        assert query == {"$or": [{"a": 1}, {"b": 1}], "c": 1}
+
+    def test_raw_and_merging(self):
+        class Doc(Document):
+            meta = {"allow_inheritance": False}
+
+        raw_query = Doc.objects(
+            __raw__={
+                "deleted": False,
+                "scraped": "yes",
+                "$nor": [
+                    {"views.extracted": "no"},
+                    {"attachments.views.extracted": "no"},
+                ],
+            }
+        )._query
+
+        assert raw_query == {
+            "deleted": False,
+            "scraped": "yes",
+            "$nor": [{"views.extracted": "no"}, {"attachments.views.extracted": "no"}],
+        }
+
+    def test_geojson_PointField(self):
+        class Location(Document):
+            loc = PointField()
+
+        update = transform.update(Location, set__loc=[1, 2])
+        assert update == {"$set": {"loc": {"type": "Point", "coordinates": [1, 2]}}}
+
+        update = transform.update(
+            Location, set__loc={"type": "Point", "coordinates": [1, 2]}
+        )
+        assert update == {"$set": {"loc": {"type": "Point", "coordinates": [1, 2]}}}
+
+    def test_geojson_LineStringField(self):
+        class Location(Document):
+            line = LineStringField()
+
+        update = transform.update(Location, set__line=[[1, 2], [2, 2]])
+        assert update == {
+            "$set": {"line": {"type": "LineString", "coordinates": [[1, 2], [2, 2]]}}
+        }
+
+        update = transform.update(
+            Location, set__line={"type": "LineString", "coordinates": [[1, 2], [2, 2]]}
+        )
+        assert update == {
+            "$set": {"line": {"type": "LineString", "coordinates": [[1, 2], [2, 2]]}}
+        }
+
+    def test_geojson_PolygonField(self):
+        class Location(Document):
+            poly = PolygonField()
+
+        update = transform.update(
+            Location, set__poly=[[[40, 5], [40, 6], [41, 6], [40, 5]]]
+        )
+        assert update == {
+            "$set": {
+                "poly": {
+                    "type": "Polygon",
+                    "coordinates": [[[40, 5], [40, 6], [41, 6], [40, 5]]],
+                }
+            }
+        }
+
+        update = transform.update(
+            Location,
+            set__poly={
+                "type": "Polygon",
+                "coordinates": [[[40, 5], [40, 6], [41, 6], [40, 5]]],
+            },
+        )
+        assert update == {
+            "$set": {
+                "poly": {
+                    "type": "Polygon",
+                    "coordinates": [[[40, 5], [40, 6], [41, 6], [40, 5]]],
+                }
+            }
+        }
+
+    def test_type(self):
+        class Doc(Document):
+            df = DynamicField()
+
+        Doc(df=True).save()
+        Doc(df=7).save()
+        Doc(df="df").save()
+        assert Doc.objects(df__type=1).count() == 0  # double
+        assert Doc.objects(df__type=8).count() == 1  # bool
+        assert Doc.objects(df__type=2).count() == 1  # str
+        assert Doc.objects(df__type=16).count() == 1  # int
+
+    def test_last_field_name_like_operator(self):
+        class EmbeddedItem(EmbeddedDocument):
+            type = StringField()
+            name = StringField()
+
+        class Doc(Document):
+            item = EmbeddedDocumentField(EmbeddedItem)
+
+        Doc.drop_collection()
+
+        doc = Doc(item=EmbeddedItem(type="axe", name="Heroic axe"))
+        doc.save()
+
+        assert 1 == Doc.objects(item__type__="axe").count()
+        assert 1 == Doc.objects(item__name__="Heroic axe").count()
+
+        Doc.objects(id=doc.id).update(set__item__type__="sword")
+        assert 1 == Doc.objects(item__type__="sword").count()
+        assert 0 == Doc.objects(item__type__="axe").count()
+
+    def test_understandable_error_raised(self):
+        class Event(Document):
+            title = StringField()
+            location = GeoPointField()
+
+        box = [(35.0, -125.0), (40.0, -100.0)]
+        # I *meant* to execute location__within_box=box
+        events = Event.objects(location__within=box)
+        with pytest.raises(InvalidQueryError):
+            events.count()
+
+    def test_update_pull_for_list_fields(self):
+        """
+        Test added to check pull operation in update for
+        EmbeddedDocumentListField which is inside a EmbeddedDocumentField
+        """
+
+        class Word(EmbeddedDocument):
+            word = StringField()
+            index = IntField()
+
+        class SubDoc(EmbeddedDocument):
+            heading = ListField(StringField())
+            text = EmbeddedDocumentListField(Word)
+
+        class MainDoc(Document):
+            title = StringField()
+            content = EmbeddedDocumentField(SubDoc)
+
+        word = Word(word="abc", index=1)
+        update = transform.update(MainDoc, pull__content__text=word)
+        assert update == {
+            "$pull": {"content.text": SON([("word", u"abc"), ("index", 1)])}
+        }
+
+        update = transform.update(MainDoc, pull__content__heading="xyz")
+        assert update == {"$pull": {"content.heading": "xyz"}}
+
+        update = transform.update(MainDoc, pull__content__text__word__in=["foo", "bar"])
+        assert update == {"$pull": {"content.text": {"word": {"$in": ["foo", "bar"]}}}}
+
+        update = transform.update(
+            MainDoc, pull__content__text__word__nin=["foo", "bar"]
+        )
+        assert update == {"$pull": {"content.text": {"word": {"$nin": ["foo", "bar"]}}}}
+
+    def test_transform_embedded_document_list_fields(self):
+        """
+        Test added to check filtering
+        EmbeddedDocumentListField which is inside a EmbeddedDocumentField
+        """
+
+        class Drink(EmbeddedDocument):
+            id = StringField()
+            meta = {"strict": False}
+
+        class Shop(Document):
+            drinks = EmbeddedDocumentListField(Drink)
+
+        Shop.drop_collection()
+        drinks = [Drink(id="drink_1"), Drink(id="drink_2")]
+        Shop.objects.create(drinks=drinks)
+        q_obj = transform.query(
+            Shop, drinks__all=[{"$elemMatch": {"_id": x.id}} for x in drinks]
+        )
+        assert q_obj == {
+            "drinks": {"$all": [{"$elemMatch": {"_id": x.id}} for x in drinks]}
+        }
+
+        Shop.drop_collection()
+
+
+if __name__ == "__main__":
+    unittest.main()