skip uri test for pymongo < v2.9

Python 2.6 is not supported anymore with version 0.11.0

CONTRIBUTING.rst

@@ -14,13 +14,13 @@ Before starting to write code, look for existing `tickets
 <https://github.com/MongoEngine/mongoengine/issues?state=open>`_ or `create one
 <https://github.com/MongoEngine/mongoengine/issues>`_ for your specific
 issue or feature request. That way you avoid working on something
-that might not be of interest or that has already been addressed.  If in doubt
+that might not be of interest or that has already been addressed. If in doubt
 post to the `user group <http://groups.google.com/group/mongoengine-users>`
 
 Supported Interpreters
 ----------------------
 
-MongoEngine supports CPython 2.6 and newer. Language
+MongoEngine supports CPython 2.7 and newer. Language
 features not supported by all interpreters can not be used.
 Please also ensure that your code is properly converted by
 `2to3 <http://docs.python.org/library/2to3.html>`_ for Python 3 support.

README.rst

@@ -35,16 +35,22 @@ setup.py install``.
 
 Dependencies
 ============
-- pymongo>=2.7.1
-- sphinx (optional - for documentation generation)
+All of the dependencies can easily be installed via `pip <https://pip.pypa.io/>`_. At the very least, you'll need these two packages to use MongoEngine:
+
+- pymongo>=2.7.1
+- six>=1.10.0
+
+If you utilize a ``DateTimeField``, you might also use a more flexible date parser:
 
-Optional Dependencies
----------------------
-- **Image Fields**: Pillow>=2.0.0
 - dateutil>=2.1.0
 
-.. note
-   MongoEngine always runs it's test suite against the latest patch version of each dependecy. e.g.: PyMongo 3.0.1
+If you need to use an ``ImageField`` or ``ImageGridFsProxy``:
+
+- Pillow>=2.0.0
+
+If you want to generate the documentation (e.g. to contribute to it):
+
+- sphinx
 
 Examples
 ========
@@ -57,7 +63,7 @@ Some simple examples of what MongoEngine code looks like:
 
     class BlogPost(Document):
         title = StringField(required=True, max_length=200)
-        posted = DateTimeField(default=datetime.datetime.now)
+        posted = DateTimeField(default=datetime.datetime.utcnow)
         tags = ListField(StringField(max_length=50))
         meta = {'allow_inheritance': True}
 
@@ -87,17 +93,18 @@ Some simple examples of what MongoEngine code looks like:
     ...     print
     ...
 
-    >>> len(BlogPost.objects)
+    # Count all blog posts and its subtypes
+    >>> BlogPost.objects.count()
     2
-    >>> len(TextPost.objects)
+    >>> TextPost.objects.count()
     1
-    >>> len(LinkPost.objects)
+    >>> LinkPost.objects.count()
     1
 
-    # Find tagged posts
-    >>> len(BlogPost.objects(tags='mongoengine'))
+    # Count tagged posts
+    >>> BlogPost.objects(tags='mongoengine').count()
     2
-    >>> len(BlogPost.objects(tags='mongodb'))
+    >>> BlogPost.objects(tags='mongodb').count()
     1
 
 Tests
@@ -130,8 +137,7 @@ Community
   <http://groups.google.com/group/mongoengine-users>`_
 - `MongoEngine Developers mailing list
   <http://groups.google.com/group/mongoengine-dev>`_
-- `#mongoengine IRC channel <http://webchat.freenode.net/?channels=mongoengine>`_
 
 Contributing
 ============
-We welcome contributions! see  the `Contribution guidelines <https://github.com/MongoEngine/mongoengine/blob/master/CONTRIBUTING.rst>`_
+We welcome contributions! See the `Contribution guidelines <https://github.com/MongoEngine/mongoengine/blob/master/CONTRIBUTING.rst>`_

docs/changelog.rst

@@ -4,13 +4,19 @@ Changelog
 
 Development
 ===========
-- (Fill this out as you fix issues and develop you features).
+- (Fill this out as you fix issues and develop your features).
+- Fixed using sets in field choices #1481
+- POTENTIAL BREAKING CHANGE: Fixed limit/skip/hint/batch_size chaining #1476
+- POTENTIAL BREAKING CHANGE: Changed a public `QuerySet.clone_into` method to a private `QuerySet._clone_into` #1476
+- Fixed connecting to a replica set with PyMongo 2.x #1436
+- Fixed an obscure error message when filtering by `field__in=non_iterable`. #1237
 
 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: Dropped Python 2.6 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: 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
 
 Changes in 0.10.8

docs/guide/connecting.rst

@@ -33,7 +33,7 @@ the :attr:`host` to
     corresponding parameters in :func:`~mongoengine.connect`: ::
 
         connect(
-            name='test',
+            db='test',
             username='user',
             password='12345',
             host='mongodb://admin:qwerty@localhost/production'

docs/guide/defining-documents.rst

@@ -150,7 +150,7 @@ arguments can be set on all fields:
     .. note:: If set, this field is also accessible through the `pk` field.
 
 :attr:`choices` (Default: None)
-    An iterable (e.g. a list or tuple) of choices to which the value of this
+    An iterable (e.g. list, tuple or set) of choices to which the value of this
     field should be limited.
 
     Can be either be a nested tuples of value (stored in mongo) and a
@@ -214,8 +214,8 @@ document class as the first argument::
 
 Dictionary Fields
 -----------------
-Often, an embedded document may be used instead of a dictionary – generally 
-embedded documents are recommended as dictionaries don’t support validation 
+Often, an embedded document may be used instead of a dictionary – generally
+embedded documents are recommended as dictionaries don’t support validation
 or custom field types. However, sometimes you will not know the structure of what you want to
 store; in this situation a :class:`~mongoengine.fields.DictField` is appropriate::
 
@@ -361,11 +361,6 @@ Its value can take any of the following constants:
    In Django, be sure to put all apps that have such delete rule declarations in
    their :file:`models.py` in the :const:`INSTALLED_APPS` tuple.
 
-
-.. warning::
-   Signals are not triggered when doing cascading updates / deletes - if this
-   is required you must manually handle the update / delete.
-
 Generic reference fields
 ''''''''''''''''''''''''
 A second kind of reference field also exists,

docs/guide/querying.rst

@@ -479,6 +479,8 @@ operators. To use a :class:`~mongoengine.queryset.Q` object, pass it in as the
 first positional argument to :attr:`Document.objects` when you filter it by
 calling it with keyword arguments::
 
+    from mongoengine.queryset.visitor import Q
+
     # Get published posts
     Post.objects(Q(published=True) | Q(publish_date__lte=datetime.now()))
 

docs/guide/signals.rst

@@ -142,11 +142,4 @@ cleaner looking while still allowing manual execution of the callback::
         modified = DateTimeField()
 
 
-ReferenceFields and Signals
----------------------------
-
-Currently `reverse_delete_rule` does not trigger signals on the other part of
-the relationship.  If this is required you must manually handle the
-reverse deletion.
-
 .. _blinker: http://pypi.python.org/pypi/blinker

docs/upgrade.rst

@@ -2,6 +2,20 @@
 Upgrading
 #########
 
+Development
+***********
+(Fill this out whenever you introduce breaking changes to MongoEngine)
+
+This release includes various fixes for the `BaseQuerySet` methods and how they
+are chained together. Since version 0.10.1 applying limit/skip/hint/batch_size
+to an already-existing queryset wouldn't modify the underlying PyMongo cursor.
+This has been fixed now, so you'll need to make sure that your code didn't rely
+on the broken implementation.
+
+Additionally, a public `BaseQuerySet.clone_into` has been renamed to a private
+`_clone_into`. If you directly used that method in your code, you'll need to
+rename its occurrences.
+
 0.11.0
 ******
 This release includes a major rehaul of MongoEngine's code quality and

mongoengine/base/common.py

@@ -5,7 +5,7 @@ __all__ = ('UPDATE_OPERATORS', 'get_document', '_document_registry')
 
 UPDATE_OPERATORS = set(['set', 'unset', 'inc', 'dec', 'pop', 'push',
                         'push_all', 'pull', 'pull_all', 'add_to_set',
-                        'set_on_insert', 'min', 'max'])
+                        'set_on_insert', 'min', 'max', 'rename'])
 
 
 _document_registry = {}

mongoengine/base/datastructures.py

@@ -138,10 +138,7 @@ class BaseList(list):
         return super(BaseList, self).__setitem__(key, value)
 
     def __delitem__(self, key, *args, **kwargs):
-        if isinstance(key, slice):
-            self._mark_as_changed()
-        else:
-            self._mark_as_changed(key)
+        self._mark_as_changed()
         return super(BaseList, self).__delitem__(key)
 
     def __setslice__(self, *args, **kwargs):
@@ -432,7 +429,7 @@ class StrictDict(object):
     def __eq__(self, other):
         return self.items() == other.items()
 
-    def __neq__(self, other):
+    def __ne__(self, other):
         return self.items() != other.items()
 
     @classmethod

mongoengine/base/document.py

@@ -402,9 +402,11 @@ class BaseDocument(object):
             raise ValidationError(message, errors=errors)
 
     def to_json(self, *args, **kwargs):
-        """Converts a document to JSON.
-        :param use_db_field: Set to True by default but enables the output of the json structure with the field names
-            and not the mongodb store db_names in case of set to False
+        """Convert this document to JSON.
+
+        :param use_db_field: Serialize field names as they appear in
+            MongoDB (as opposed to attribute names on this document).
+            Defaults to True.
         """
         use_db_field = kwargs.pop('use_db_field', True)
         return json_util.dumps(self.to_mongo(use_db_field), *args, **kwargs)
@@ -675,6 +677,9 @@ class BaseDocument(object):
         if not only_fields:
             only_fields = []
 
+        if son and not isinstance(son, dict):
+            raise ValueError("The source SON object needs to be of type 'dict'")
+
         # Get the class name from the document, falling back to the given
         # class if unavailable
         class_name = son.get('_cls', cls._class_name)

mongoengine/base/fields.py

@@ -41,7 +41,7 @@ class BaseField(object):
         """
         :param db_field: The database field to store this field in
             (defaults to the name of the field)
-        :param name: Depreciated - use db_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
@@ -81,6 +81,17 @@ class BaseField(object):
         self.sparse = sparse
         self._owner_document = None
 
+        # Validate the db_field
+        if isinstance(self.db_field, six.string_types) and (
+            '.' in self.db_field or
+            '\0' in self.db_field or
+            self.db_field.startswith('$')
+        ):
+            raise ValueError(
+                'field names cannot contain dots (".") or null characters '
+                '("\\0"), and they must not start with a dollar sign ("$").'
+            )
+
         # Detect and report conflicts between metadata and base properties.
         conflicts = set(dir(self)) & set(kwargs)
         if conflicts:
@@ -182,7 +193,8 @@ class BaseField(object):
         EmbeddedDocument = _import_class('EmbeddedDocument')
 
         choice_list = self.choices
-        if isinstance(choice_list[0], (list, tuple)):
+        if isinstance(next(iter(choice_list)), (list, tuple)):
+            # next(iter) is useful for sets
             choice_list = [k for k, _ in choice_list]
 
         # Choices which are other types of Documents

mongoengine/common.py

@@ -34,7 +34,10 @@ def _import_class(cls_name):
     queryset_classes = ('OperationError',)
     deref_classes = ('DeReference',)
 
-    if cls_name in doc_classes:
+    if cls_name == 'BaseDocument':
+        from mongoengine.base import document as module
+        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:

mongoengine/connection.py

@@ -51,7 +51,9 @@ def register_connection(alias, name=None, host=None, port=None,
         MONGODB-CR (MongoDB Challenge Response protocol) for older servers.
     :param is_mock: explicitly use mongomock for this connection
         (can also be done by using `mongomock://` as db host prefix)
-    :param kwargs: allow ad-hoc parameters to be passed into the pymongo driver
+    :param kwargs: ad-hoc parameters to be passed into the pymongo driver,
+        for example maxpoolsize, tz_aware, etc. See the documentation
+        for pymongo's `MongoClient` for a full list.
 
     .. versionchanged:: 0.10.6 - added mongomock support
     """
@@ -66,9 +68,9 @@ def register_connection(alias, name=None, host=None, port=None,
         'authentication_mechanism': authentication_mechanism
     }
 
-    # Handle uri style connections
     conn_host = conn_settings['host']
-    # host can be a list or a string, so if string, force to a list
+
+    # Host can be a list or a string, so if string, force to a list.
     if isinstance(conn_host, six.string_types):
         conn_host = [conn_host]
 
@@ -96,7 +98,7 @@ def register_connection(alias, name=None, host=None, port=None,
 
             uri_options = uri_dict['options']
             if 'replicaset' in uri_options:
-                conn_settings['replicaSet'] = True
+                conn_settings['replicaSet'] = uri_options['replicaset']
             if 'authsource' in uri_options:
                 conn_settings['authentication_source'] = uri_options['authsource']
             if 'authmechanism' in uri_options:
@@ -170,23 +172,22 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
     else:
         connection_class = MongoClient
 
-        # Handle replica set connections
-        if 'replicaSet' in conn_settings:
+        # For replica set connections with PyMongo 2.x, use
+        # MongoReplicaSetClient.
+        # TODO remove this once we stop supporting PyMongo 2.x.
+        if 'replicaSet' in conn_settings and not IS_PYMONGO_3:
+            connection_class = MongoReplicaSetClient
+            conn_settings['hosts_or_uri'] = conn_settings.pop('host', None)
+
+            # hosts_or_uri has to be a string, so if 'host' was provided
+            # as a list, join its parts and separate them by ','
+            if isinstance(conn_settings['hosts_or_uri'], list):
+                conn_settings['hosts_or_uri'] = ','.join(
+                    conn_settings['hosts_or_uri'])
 
             # Discard port since it can't be used on MongoReplicaSetClient
             conn_settings.pop('port', None)
 
-            # Discard replicaSet if it's not a string
-            if not isinstance(conn_settings['replicaSet'], six.string_types):
-                del conn_settings['replicaSet']
-
-            # For replica set connections with PyMongo 2.x, use
-            # MongoReplicaSetClient.
-            # TODO remove this once we stop supporting PyMongo 2.x.
-            if not IS_PYMONGO_3:
-                connection_class = MongoReplicaSetClient
-                conn_settings['hosts_or_uri'] = conn_settings.pop('host', None)
-
     # Iterate over all of the connection settings and if a connection with
     # the same parameters is already established, use it instead of creating
     # a new one.
@@ -242,9 +243,12 @@ def connect(db=None, alias=DEFAULT_CONNECTION_NAME, **kwargs):
     running on the default port on localhost. If authentication is needed,
     provide username and password arguments as well.
 
-    Multiple databases are supported by using aliases.  Provide a separate
+    Multiple databases are supported by using aliases. Provide a separate
     `alias` to connect to a different instance of :program:`mongod`.
 
+    See the docstring for `register_connection` for more details about all
+    supported kwargs.
+
     .. versionchanged:: 0.6 - added multiple database support.
     """
     if alias not in _connections:

mongoengine/document.py

@@ -313,6 +313,9 @@ class Document(BaseDocument):
         .. versionchanged:: 0.10.7
             Add signal_kwargs argument
         """
+        if self._meta.get('abstract'):
+            raise InvalidDocumentError('Cannot save an abstract document.')
+
         signal_kwargs = signal_kwargs or {}
         signals.pre_save.send(self.__class__, document=self, **signal_kwargs)
 
@@ -329,68 +332,20 @@ class Document(BaseDocument):
         signals.pre_save_post_validation.send(self.__class__, document=self,
                                               created=created, **signal_kwargs)
 
+        if self._meta.get('auto_create_index', True):
+            self.ensure_indexes()
+
         try:
-            collection = self._get_collection()
-            if self._meta.get('auto_create_index', True):
-                self.ensure_indexes()
+            # Save a new document or update an existing one
             if created:
-                if force_insert:
-                    object_id = collection.insert(doc, **write_concern)
-                else:
-                    object_id = collection.save(doc, **write_concern)
-                    # In PyMongo 3.0, the save() call calls internally the _update() call
-                    # but they forget to return the _id value passed back, therefore getting it back here
-                    # Correct behaviour in 2.X and in 3.0.1+ versions
-                    if not object_id and pymongo.version_tuple == (3, 0):
-                        pk_as_mongo_obj = self._fields.get(self._meta['id_field']).to_mongo(self.pk)
-                        object_id = (
-                            self._qs.filter(pk=pk_as_mongo_obj).first() and
-                            self._qs.filter(pk=pk_as_mongo_obj).first().pk
-                        )  # TODO doesn't this make 2 queries?
+                object_id = self._save_create(doc, force_insert, write_concern)
             else:
-                object_id = doc['_id']
-                updates, removals = self._delta()
-                # Need to add shard key to query, or you get an error
-                if save_condition is not None:
-                    select_dict = transform.query(self.__class__,
-                                                  **save_condition)
-                else:
-                    select_dict = {}
-                select_dict['_id'] = object_id
-                shard_key = self._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 = doc
-                    for ak in actual_key:
-                        val = val[ak]
-                    select_dict['.'.join(actual_key)] = val
-
-                def is_new_object(last_error):
-                    if last_error is not None:
-                        updated = last_error.get('updatedExisting')
-                        if updated is not None:
-                            return not updated
-                    return created
-
-                update_query = {}
-
-                if updates:
-                    update_query['$set'] = updates
-                if removals:
-                    update_query['$unset'] = removals
-                if updates or removals:
-                    upsert = save_condition is None
-                    last_error = collection.update(select_dict, update_query,
-                                                   upsert=upsert, **write_concern)
-                    if not upsert and last_error['n'] == 0:
-                        raise SaveConditionError('Race condition preventing'
-                                                 ' document update detected')
-                    created = is_new_object(last_error)
+                object_id, created = self._save_update(doc, save_condition,
+                                                       write_concern)
 
             if cascade is None:
-                cascade = self._meta.get(
-                    'cascade', False) or cascade_kwargs is not None
+                cascade = (self._meta.get('cascade', False) or
+                           cascade_kwargs is not None)
 
             if cascade:
                 kwargs = {
@@ -403,6 +358,7 @@ class Document(BaseDocument):
                     kwargs.update(cascade_kwargs)
                 kwargs['_refs'] = _refs
                 self.cascade_save(**kwargs)
+
         except pymongo.errors.DuplicateKeyError as err:
             message = u'Tried to save duplicate unique keys (%s)'
             raise NotUniqueError(message % six.text_type(err))
@@ -415,16 +371,91 @@ class Document(BaseDocument):
                 raise NotUniqueError(message % six.text_type(err))
             raise OperationError(message % six.text_type(err))
 
+        # Make sure we store the PK on this document now that it's saved
         id_field = self._meta['id_field']
         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,
                                created=created, **signal_kwargs)
+
         self._clear_changed_fields()
         self._created = False
+
         return self
 
+    def _save_create(self, doc, force_insert, write_concern):
+        """Save a new document.
+
+        Helper method, should only be used inside save().
+        """
+        collection = self._get_collection()
+
+        if force_insert:
+            return collection.insert(doc, **write_concern)
+
+        object_id = collection.save(doc, **write_concern)
+
+        # In PyMongo 3.0, the save() call calls internally the _update() call
+        # but they forget to return the _id value passed back, therefore getting it back here
+        # Correct behaviour in 2.X and in 3.0.1+ versions
+        if not object_id and pymongo.version_tuple == (3, 0):
+            pk_as_mongo_obj = self._fields.get(self._meta['id_field']).to_mongo(self.pk)
+            object_id = (
+                self._qs.filter(pk=pk_as_mongo_obj).first() and
+                self._qs.filter(pk=pk_as_mongo_obj).first().pk
+            )  # TODO doesn't this make 2 queries?
+
+        return object_id
+
+    def _save_update(self, doc, save_condition, write_concern):
+        """Update an existing document.
+
+        Helper method, should only be used inside save().
+        """
+        collection = self._get_collection()
+        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
+
+        # Need to add shard key to query, or you get an error
+        shard_key = self._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 = doc
+            for ak in actual_key:
+                val = val[ak]
+            select_dict['.'.join(actual_key)] = val
+
+        updates, removals = self._delta()
+        update_query = {}
+        if updates:
+            update_query['$set'] = updates
+        if removals:
+            update_query['$unset'] = removals
+        if updates or removals:
+            upsert = save_condition is None
+            last_error = collection.update(select_dict, update_query,
+                                           upsert=upsert, **write_concern)
+            if not upsert and last_error['n'] == 0:
+                raise SaveConditionError('Race condition preventing'
+                                         ' document update detected')
+            if last_error is not None:
+                updated_existing = last_error.get('updatedExisting')
+                if updated_existing is False:
+                    created = True
+                    # !!! This is bad, means we accidentally created a new,
+                    # potentially corrupted document. See
+                    # https://github.com/MongoEngine/mongoengine/issues/564
+
+        return object_id, created
+
     def cascade_save(self, **kwargs):
         """Recursively save any references and generic references on the
         document.
@@ -828,7 +859,6 @@ class Document(BaseDocument):
         """ 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'):
             return []
 

mongoengine/errors.py

@@ -50,8 +50,8 @@ class FieldDoesNotExist(Exception):
     or an :class:`~mongoengine.EmbeddedDocument`.
 
     To avoid this behavior on data loading,
-    you should the :attr:`strict` to ``False``
-    in the :attr:`meta` dictionnary.
+    you should set the :attr:`strict` to ``False``
+    in the :attr:`meta` dictionary.
     """
 
 

mongoengine/fields.py

@@ -28,7 +28,7 @@ from mongoengine.base import (BaseDocument, BaseField, ComplexBaseField,
                               GeoJsonBaseField, ObjectIdField, get_document)
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.document import Document, EmbeddedDocument
-from mongoengine.errors import DoesNotExist, ValidationError
+from mongoengine.errors import DoesNotExist, InvalidQueryError, ValidationError
 from mongoengine.python_support import StringIO
 from mongoengine.queryset import DO_NOTHING, QuerySet
 
@@ -139,12 +139,12 @@ class URLField(StringField):
         # Check first if the scheme is valid
         scheme = value.split('://')[0].lower()
         if scheme not in self.schemes:
-            self.error('Invalid scheme {} in URL: {}'.format(scheme, value))
+            self.error(u'Invalid scheme {} in URL: {}'.format(scheme, value))
             return
 
         # Then check full URL
         if not self.url_regex.match(value):
-            self.error('Invalid URL: {}'.format(value))
+            self.error(u'Invalid URL: {}'.format(value))
             return
 
 
@@ -566,7 +566,11 @@ class EmbeddedDocumentField(BaseField):
 
     def prepare_query_value(self, op, value):
         if value is not None and not isinstance(value, self.document_type):
-            value = self.document_type._from_son(value)
+            try:
+                value = self.document_type._from_son(value)
+            except ValueError:
+                raise InvalidQueryError("Querying the embedded document '%s' failed, due to an invalid query value" %
+                                        (self.document_type._class_name,))
         super(EmbeddedDocumentField, self).prepare_query_value(op, value)
         return self.to_mongo(value)
 
@@ -884,10 +888,6 @@ class ReferenceField(BaseField):
 
         Foo.register_delete_rule(Bar, 'foo', NULLIFY)
 
-    .. note ::
-        `reverse_delete_rule` does not trigger pre / post delete signals to be
-        triggered.
-
     .. versionchanged:: 0.5 added `reverse_delete_rule`
     """
 

mongoengine/queryset/base.py

@@ -86,6 +86,7 @@ class BaseQuerySet(object):
         self._batch_size = None
         self.only_fields = []
         self._max_time_ms = None
+        self._comment = None
 
     def __call__(self, q_obj=None, class_check=True, read_preference=None,
                  **query):
@@ -706,39 +707,36 @@ class BaseQuerySet(object):
         with switch_db(self._document, alias) as cls:
             collection = cls._get_collection()
 
-        return self.clone_into(self.__class__(self._document, collection))
+        return self._clone_into(self.__class__(self._document, collection))
 
     def clone(self):
-        """Creates a copy of the current
-          :class:`~mongoengine.queryset.QuerySet`
+        """Create a copy of the current queryset."""
+        return self._clone_into(self.__class__(self._document, self._collection_obj))
 
-        .. versionadded:: 0.5
+    def _clone_into(self, new_qs):
+        """Copy all of the relevant properties of this queryset to
+        a new queryset (which has to be an instance of
+        :class:`~mongoengine.queryset.base.BaseQuerySet`).
         """
-        return self.clone_into(self.__class__(self._document, self._collection_obj))
-
-    def clone_into(self, cls):
-        """Creates a copy of the current
-          :class:`~mongoengine.queryset.base.BaseQuerySet` into another child class
-        """
-        if not isinstance(cls, BaseQuerySet):
+        if not isinstance(new_qs, BaseQuerySet):
             raise OperationError(
-                '%s is not a subclass of BaseQuerySet' % cls.__name__)
+                '%s is not a subclass of BaseQuerySet' % new_qs.__name__)
 
         copy_props = ('_mongo_query', '_initial_query', '_none', '_query_obj',
                       '_where_clause', '_loaded_fields', '_ordering', '_snapshot',
                       '_timeout', '_class_check', '_slave_okay', '_read_preference',
                       '_iter', '_scalar', '_as_pymongo', '_as_pymongo_coerce',
                       '_limit', '_skip', '_hint', '_auto_dereference',
-                      '_search_text', 'only_fields', '_max_time_ms')
+                      '_search_text', 'only_fields', '_max_time_ms', '_comment')
 
         for prop in copy_props:
             val = getattr(self, prop)
-            setattr(cls, prop, copy.copy(val))
+            setattr(new_qs, prop, copy.copy(val))
 
         if self._cursor_obj:
-            cls._cursor_obj = self._cursor_obj.clone()
+            new_qs._cursor_obj = self._cursor_obj.clone()
 
-        return cls
+        return new_qs
 
     def select_related(self, max_depth=1):
         """Handles dereferencing of :class:`~bson.dbref.DBRef` objects or
@@ -760,7 +758,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._limit = n if n != 0 else 1
-        # Return self to allow chaining
+
+        # If a cursor object has already been created, apply the limit to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.limit(queryset._limit)
+
         return queryset
 
     def skip(self, n):
@@ -771,6 +773,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._skip = n
+
+        # If a cursor object has already been created, apply the skip to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.skip(queryset._skip)
+
         return queryset
 
     def hint(self, index=None):
@@ -788,6 +795,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._hint = index
+
+        # If a cursor object has already been created, apply the hint to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.hint(queryset._hint)
+
         return queryset
 
     def batch_size(self, size):
@@ -801,6 +813,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._batch_size = size
+
+        # If a cursor object has already been created, apply the batch size to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.batch_size(queryset._batch_size)
+
         return queryset
 
     def distinct(self, field):
@@ -900,18 +917,24 @@ class BaseQuerySet(object):
         return self.fields(**fields)
 
     def fields(self, _only_called=False, **kwargs):
-        """Manipulate how you load this document's fields.  Used by `.only()`
-        and `.exclude()` to manipulate which fields to retrieve.  Fields also
-        allows for a greater level of control for example:
+        """Manipulate how you load this document's fields. Used by `.only()`
+        and `.exclude()` to manipulate which fields to retrieve. If called
+        directly, use a set of kwargs similar to the MongoDB projection
+        document. For example:
 
-        Retrieving a Subrange of Array Elements:
+        Include only a subset of fields:
 
-        You can use the $slice operator to retrieve a subrange of elements in
-        an array. For example to get the first 5 comments::
+            posts = BlogPost.objects(...).fields(author=1, title=1)
 
-            post = BlogPost.objects(...).fields(slice__comments=5)
+        Exclude a specific field:
 
-        :param kwargs: A dictionary identifying what to include
+            posts = BlogPost.objects(...).fields(comments=0)
+
+        To retrieve a subrange of array elements:
+
+            posts = BlogPost.objects(...).fields(slice__comments=5)
+
+        :param kwargs: A set keywors arguments identifying what to include.
 
         .. versionadded:: 0.5
         """
@@ -927,7 +950,20 @@ class BaseQuerySet(object):
             key = '.'.join(parts)
             cleaned_fields.append((key, value))
 
-        fields = sorted(cleaned_fields, key=operator.itemgetter(1))
+        # Sort fields by their values, explicitly excluded fields first, then
+        # explicitly included, and then more complicated operators such as
+        # $slice.
+        def _sort_key(field_tuple):
+            key, value = field_tuple
+            if isinstance(value, (int)):
+                return value  # 0 for exclusion, 1 for inclusion
+            else:
+                return 2  # so that complex values appear last
+
+        fields = sorted(cleaned_fields, key=_sort_key)
+
+        # Clone the queryset, group all fields by their value, convert
+        # each of them to db_fields, and set the queryset's _loaded_fields
         queryset = self.clone()
         for value, group in itertools.groupby(fields, lambda x: x[1]):
             fields = [field for field, value in group]
@@ -953,13 +989,31 @@ class BaseQuerySet(object):
     def order_by(self, *keys):
         """Order the :class:`~mongoengine.queryset.QuerySet` by the keys. The
         order may be specified by prepending each of the keys by a + or a -.
-        Ascending order is assumed.
+        Ascending order is assumed. If no keys are passed, existing ordering
+        is cleared instead.
 
         :param keys: fields to order the query results by; keys may be
             prefixed with **+** or **-** to determine the ordering direction
         """
         queryset = self.clone()
-        queryset._ordering = queryset._get_order_by(keys)
+
+        old_ordering = queryset._ordering
+        new_ordering = queryset._get_order_by(keys)
+
+        if queryset._cursor_obj:
+
+            # If a cursor object has already been created, apply the sort to it
+            if new_ordering:
+                queryset._cursor_obj.sort(new_ordering)
+
+            # If we're trying to clear a previous explicit ordering, we need
+            # to clear the cursor entirely (because PyMongo doesn't allow
+            # clearing an existing sort on a cursor).
+            elif old_ordering:
+                queryset._cursor_obj = None
+
+        queryset._ordering = new_ordering
+
         return queryset
 
     def comment(self, text):
@@ -1405,10 +1459,13 @@ class BaseQuerySet(object):
             raise StopIteration
 
         raw_doc = self._cursor.next()
+
         if self._as_pymongo:
             return self._get_as_pymongo(raw_doc)
-        doc = self._document._from_son(raw_doc,
-                                       _auto_dereference=self._auto_dereference, only_fields=self.only_fields)
+
+        doc = self._document._from_son(
+            raw_doc, _auto_dereference=self._auto_dereference,
+            only_fields=self.only_fields)
 
         if self._scalar:
             return self._get_scalar(doc)
@@ -1418,7 +1475,6 @@ class BaseQuerySet(object):
     def rewind(self):
         """Rewind the cursor to its unevaluated state.
 
-
         .. versionadded:: 0.3
         """
         self._iter = False
@@ -1468,43 +1524,54 @@ class BaseQuerySet(object):
 
     @property
     def _cursor(self):
-        if self._cursor_obj is None:
+        """Return a PyMongo cursor object corresponding to this queryset."""
 
-            # In PyMongo 3+, we define the read preference on a collection
-            # level, not a cursor level. Thus, we need to get a cloned
-            # collection object using `with_options` first.
-            if IS_PYMONGO_3 and self._read_preference is not None:
-                self._cursor_obj = self._collection\
-                    .with_options(read_preference=self._read_preference)\
-                    .find(self._query, **self._cursor_args)
-            else:
-                self._cursor_obj = self._collection.find(self._query,
-                                                         **self._cursor_args)
-            # Apply where clauses to cursor
-            if self._where_clause:
-                where_clause = self._sub_js_fields(self._where_clause)
-                self._cursor_obj.where(where_clause)
+        # If _cursor_obj already exists, return it immediately.
+        if self._cursor_obj is not None:
+            return self._cursor_obj
 
-            if self._ordering:
-                # Apply query ordering
-                self._cursor_obj.sort(self._ordering)
-            elif self._ordering is None and self._document._meta['ordering']:
-                # Otherwise, apply the ordering from the document model, unless
-                # it's been explicitly cleared via order_by with no arguments
-                order = self._get_order_by(self._document._meta['ordering'])
-                self._cursor_obj.sort(order)
+        # Create a new PyMongo cursor.
+        # XXX In PyMongo 3+, we define the read preference on a collection
+        # level, not a cursor level. Thus, we need to get a cloned collection
+        # object using `with_options` first.
+        if IS_PYMONGO_3 and self._read_preference is not None:
+            self._cursor_obj = self._collection\
+                .with_options(read_preference=self._read_preference)\
+                .find(self._query, **self._cursor_args)
+        else:
+            self._cursor_obj = self._collection.find(self._query,
+                                                     **self._cursor_args)
+        # Apply "where" clauses to cursor
+        if self._where_clause:
+            where_clause = self._sub_js_fields(self._where_clause)
+            self._cursor_obj.where(where_clause)
 
-            if self._limit is not None:
-                self._cursor_obj.limit(self._limit)
+        # Apply ordering to the cursor.
+        # XXX self._ordering can be equal to:
+        # * None if we didn't explicitly call order_by on this queryset.
+        # * A list of PyMongo-style sorting tuples.
+        # * An empty list if we explicitly called order_by() without any
+        #   arguments. This indicates that we want to clear the default
+        #   ordering.
+        if self._ordering:
+            # explicit ordering
+            self._cursor_obj.sort(self._ordering)
+        elif self._ordering is None and self._document._meta['ordering']:
+            # default ordering
+            order = self._get_order_by(self._document._meta['ordering'])
+            self._cursor_obj.sort(order)
 
-            if self._skip is not None:
-                self._cursor_obj.skip(self._skip)
+        if self._limit is not None:
+            self._cursor_obj.limit(self._limit)
 
-            if self._hint != -1:
-                self._cursor_obj.hint(self._hint)
+        if self._skip is not None:
+            self._cursor_obj.skip(self._skip)
 
-            if self._batch_size is not None:
-                self._cursor_obj.batch_size(self._batch_size)
+        if self._hint != -1:
+            self._cursor_obj.hint(self._hint)
+
+        if self._batch_size is not None:
+            self._cursor_obj.batch_size(self._batch_size)
 
         return self._cursor_obj
 
@@ -1679,7 +1746,13 @@ class BaseQuerySet(object):
         return ret
 
     def _get_order_by(self, keys):
-        """Creates a list of order by fields"""
+        """Given a list of MongoEngine-style sort keys, return a list
+        of sorting tuples that can be applied to a PyMongo cursor. For
+        example:
+
+        >>> qs._get_order_by(['-last_name', 'first_name'])
+        [('last_name', -1), ('first_name', 1)]
+        """
         key_list = []
         for key in keys:
             if not key:
@@ -1692,17 +1765,19 @@ class BaseQuerySet(object):
             direction = pymongo.ASCENDING
             if key[0] == '-':
                 direction = pymongo.DESCENDING
+
             if key[0] in ('-', '+'):
                 key = key[1:]
+
             key = key.replace('__', '.')
             try:
                 key = self._document._translate_field_name(key)
             except Exception:
+                # TODO this exception should be more specific
                 pass
+
             key_list.append((key, direction))
 
-        if self._cursor_obj and key_list:
-            self._cursor_obj.sort(key_list)
         return key_list
 
     def _get_scalar(self, doc):
@@ -1800,10 +1875,21 @@ class BaseQuerySet(object):
         return code
 
     def _chainable_method(self, method_name, val):
+        """Call a particular method on the PyMongo cursor call a particular chainable method
+        with the provided value.
+        """
         queryset = self.clone()
-        method = getattr(queryset._cursor, method_name)
-        method(val)
+
+        # Get an existing cursor object or create a new one
+        cursor = queryset._cursor
+
+        # Find the requested method on the cursor and call it with the
+        # provided value
+        getattr(cursor, method_name)(val)
+
+        # Cache the value on the queryset._{method_name}
         setattr(queryset, '_' + method_name, val)
+
         return queryset
 
     # Deprecated

mongoengine/queryset/queryset.py

@@ -136,13 +136,15 @@ class QuerySet(BaseQuerySet):
         return self._len
 
     def no_cache(self):
-        """Convert to a non_caching queryset
+        """Convert to a non-caching queryset
 
         .. versionadded:: 0.8.3 Convert to non caching queryset
         """
         if self._result_cache is not None:
             raise OperationError('QuerySet already cached')
-        return self.clone_into(QuerySetNoCache(self._document, self._collection))
+
+        return self._clone_into(QuerySetNoCache(self._document,
+                                                self._collection))
 
 
 class QuerySetNoCache(BaseQuerySet):
@@ -153,7 +155,7 @@ class QuerySetNoCache(BaseQuerySet):
 
         .. versionadded:: 0.8.3 Convert to caching queryset
         """
-        return self.clone_into(QuerySet(self._document, self._collection))
+        return self._clone_into(QuerySet(self._document, self._collection))
 
     def __repr__(self):
         """Provides the string representation of the QuerySet

mongoengine/queryset/transform.py

@@ -101,8 +101,21 @@ def query(_doc_cls=None, **kwargs):
                         value = value['_id']
 
             elif op in ('in', 'nin', 'all', 'near') and not isinstance(value, dict):
-                # 'in', 'nin' and 'all' require a list of values
-                value = [field.prepare_query_value(op, v) for v in value]
+                # Raise an error if the in/nin/all/near param is not iterable. 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')
+                if isinstance(value, BaseDocument):
+                    raise TypeError("When using the `in`, `nin`, `all`, or "
+                                    "`near`-operators you can\'t use a "
+                                    "`Document`, you must wrap your object "
+                                    "in a list (object -> [object]).")
+                elif not hasattr(value, '__iter__'):
+                    raise TypeError("The `in`, `nin`, `all`, or "
+                                    "`near`-operators must be applied to an "
+                                    "iterable (e.g. a list).")
+                else:
+                    value = [field.prepare_query_value(op, v) for v in value]
 
             # If we're querying a GenericReferenceField, we need to alter the
             # key depending on the value:
@@ -220,8 +233,7 @@ def update(_doc_cls=None, **update):
                 # Support decrement by flipping a positive value's sign
                 # and using 'inc'
                 op = 'inc'
-                if value > 0:
-                    value = -value
+                value = -value
             elif op == 'add_to_set':
                 op = 'addToSet'
             elif op == 'set_on_insert':

setup.cfg

@@ -7,5 +7,5 @@ cover-package=mongoengine
 [flake8]
 ignore=E501,F401,F403,F405,I201
 exclude=build,dist,docs,venv,venv3,.tox,.eggs,tests
-max-complexity=45
+max-complexity=47
 application-import-names=mongoengine,tests

tests/document/instance.py

@@ -435,6 +435,15 @@ class InstanceTest(unittest.TestCase):
 
         person.to_dbref()
 
+    def test_save_abstract_document(self):
+        """Saving an abstract document should fail."""
+        class Doc(Document):
+            name = StringField()
+            meta = {'abstract': True}
+
+        with self.assertRaises(InvalidDocumentError):
+            Doc(name='aaa').save()
+
     def test_reload(self):
         """Ensure that attributes may be reloaded.
         """
@@ -1223,6 +1232,19 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(person.name, None)
         self.assertEqual(person.age, None)
 
+    def test_update_rename_operator(self):
+        """Test the $rename operator."""
+        coll = self.Person._get_collection()
+        doc = self.Person(name='John').save()
+        raw_doc = coll.find_one({'_id': doc.pk})
+        self.assertEqual(set(raw_doc.keys()), set(['_id', '_cls', 'name']))
+
+        doc.update(rename__name='first_name')
+        raw_doc = coll.find_one({'_id': doc.pk})
+        self.assertEqual(set(raw_doc.keys()),
+                         set(['_id', '_cls', 'first_name']))
+        self.assertEqual(raw_doc['first_name'], 'John')
+
     def test_inserts_if_you_set_the_pk(self):
         p1 = self.Person(name='p1', id=bson.ObjectId()).save()
         p2 = self.Person(name='p2')
@@ -1860,6 +1882,10 @@ class InstanceTest(unittest.TestCase):
                 'occurs': {"hello": None}
             })
 
+        # Tests for issue #1438: https://github.com/MongoEngine/mongoengine/issues/1438
+        with self.assertRaises(ValueError):
+            Word._from_son('this is not a valid SON dict')
+
     def test_reverse_delete_rule_cascade_and_nullify(self):
         """Ensure that a referenced document is also deleted upon deletion.
         """

tests/fields/fields.py

@@ -1,13 +1,12 @@
 # -*- coding: utf-8 -*-
-import six
-from nose.plugins.skip import SkipTest
-
 import datetime
 import unittest
 import uuid
 import math
 import itertools
 import re
+
+from nose.plugins.skip import SkipTest
 import six
 
 try:
@@ -27,21 +26,13 @@ from mongoengine import *
 from mongoengine.connection import get_db
 from mongoengine.base import (BaseDict, BaseField, EmbeddedDocumentList,
                               _document_registry)
-from mongoengine.errors import NotRegistered, DoesNotExist
+
+from tests.utils import MongoDBTestCase
 
 __all__ = ("FieldTest", "EmbeddedDocumentListFieldTestCase")
 
 
-class FieldTest(unittest.TestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-        self.db = get_db()
-
-    def tearDown(self):
-        self.db.drop_collection('fs.files')
-        self.db.drop_collection('fs.chunks')
-        self.db.drop_collection('mongoengine.counters')
+class FieldTest(MongoDBTestCase):
 
     def test_default_values_nothing_set(self):
         """Ensure that default field values are used when creating a document.
@@ -227,9 +218,9 @@ class FieldTest(unittest.TestCase):
         self.assertTrue(isinstance(ret.comp_dt_fld, datetime.datetime))
 
     def test_not_required_handles_none_from_database(self):
-        """Ensure that every fields can handle null values from the database.
+        """Ensure that every field can handle null values from the
+        database.
         """
-
         class HandleNoneFields(Document):
             str_fld = StringField(required=True)
             int_fld = IntField(required=True)
@@ -306,6 +297,24 @@ class FieldTest(unittest.TestCase):
         person.id = '497ce96f395f2f052a494fd4'
         person.validate()
 
+    def test_db_field_validation(self):
+        """Ensure that db_field doesn't accept invalid values."""
+
+        # dot in the name
+        with self.assertRaises(ValueError):
+            class User(Document):
+                name = StringField(db_field='user.name')
+
+        # name starting with $
+        with self.assertRaises(ValueError):
+            class User(Document):
+                name = StringField(db_field='$name')
+
+        # name containing a null character
+        with self.assertRaises(ValueError):
+            class User(Document):
+                name = StringField(db_field='name\0')
+
     def test_string_validation(self):
         """Ensure that invalid values cannot be assigned to string fields.
         """
@@ -332,11 +341,12 @@ class FieldTest(unittest.TestCase):
         person.validate()
 
     def test_url_validation(self):
-        """Ensure that URLFields validate urls properly.
-        """
+        """Ensure that URLFields validate urls properly."""
         class Link(Document):
             url = URLField()
 
+        Link.drop_collection()
+
         link = Link()
         link.url = 'google'
         self.assertRaises(ValidationError, link.validate)
@@ -344,6 +354,27 @@ class FieldTest(unittest.TestCase):
         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.drop_collection()
+
+        link = Link()
+        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
+        try:
+            link.validate()
+            self.assertTrue(False)
+        except ValidationError as e:
+            self.assertEqual(
+                unicode(e),
+                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.
         """
@@ -1042,6 +1073,7 @@ class FieldTest(unittest.TestCase):
         self.assertEqual(
             BlogPost.objects.filter(info__100__test__exact='test').count(), 0)
 
+        # test queries by list
         post = BlogPost()
         post.info = ['1', '2']
         post.save()
@@ -1053,6 +1085,248 @@ class FieldTest(unittest.TestCase):
         post.info *= 2
         post.save()
         self.assertEqual(BlogPost.objects(info=['1', '2', '3', '4', '1', '2', '3', '4']).count(), 1)
+
+        BlogPost.drop_collection()
+
+    def test_list_field_manipulative_operators(self):
+        """Ensure that ListField works with standard list operators that manipulate the list.
+        """
+        class BlogPost(Document):
+            ref = StringField()
+            info = ListField(StringField())
+
+        BlogPost.drop_collection()
+
+        post = BlogPost()
+        post.ref = "1234"
+        post.info = ['0', '1', '2', '3', '4', '5']
+        post.save()
+
+        def reset_post():
+            post.info = ['0', '1', '2', '3', '4', '5']
+            post.save()
+
+        # '__add__(listB)'
+        # listA+listB
+        # operator.add(listA, listB)
+        reset_post()
+        temp = ['a', 'b']
+        post.info = post.info + temp
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'a', 'b'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'a', 'b'])
+
+        # '__delitem__(index)'
+        # aka 'del list[index]'
+        # aka 'operator.delitem(list, index)'
+        reset_post()
+        del post.info[2] # del from middle ('2')
+        self.assertEqual(post.info, ['0', '1', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '3', '4', '5'])
+
+        # '__delitem__(slice(i, j))'
+        # aka 'del list[i:j]'
+        # aka 'operator.delitem(list, slice(i,j))'
+        reset_post()
+        del post.info[1:3] # removes '1', '2'
+        self.assertEqual(post.info, ['0', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '3', '4', '5'])
+
+        # '__iadd__'
+        # aka 'list += list'
+        reset_post()
+        temp = ['a', 'b']
+        post.info += temp
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'a', 'b'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'a', 'b'])
+
+        # '__imul__'
+        # aka 'list *= number'
+        reset_post()
+        post.info *= 2
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', '0', '1', '2', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', '0', '1', '2', '3', '4', '5'])
+
+        # '__mul__'
+        # aka 'listA*listB'
+        reset_post()
+        post.info = post.info * 2
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', '0', '1', '2', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', '0', '1', '2', '3', '4', '5'])
+
+        # '__rmul__'
+        # aka 'listB*listA'
+        reset_post()
+        post.info = 2 * post.info
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', '0', '1', '2', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', '0', '1', '2', '3', '4', '5'])
+
+        # '__setitem__(index, value)'
+        # aka 'list[index]=value'
+        # aka 'setitem(list, value)'
+        reset_post()
+        post.info[4] = 'a'
+        self.assertEqual(post.info, ['0', '1', '2', '3', 'a', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', 'a', '5'])
+
+        # '__setitem__(slice(i, j), listB)'
+        # aka 'listA[i:j] = listB'
+        # aka 'setitem(listA, slice(i, j), listB)'
+        reset_post()
+        post.info[1:3] = ['h', 'e', 'l', 'l', 'o']
+        self.assertEqual(post.info, ['0', 'h', 'e', 'l', 'l', 'o', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', 'h', 'e', 'l', 'l', 'o', '3', '4', '5'])
+
+        # 'append'
+        reset_post()
+        post.info.append('h')
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'h'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'h'])
+
+        # 'extend'
+        reset_post()
+        post.info.extend(['h', 'e', 'l', 'l', 'o'])
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'h', 'e', 'l', 'l', 'o'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '2', '3', '4', '5', 'h', 'e', 'l', 'l', 'o'])
+        # 'insert'
+
+        # 'pop'
+        reset_post()
+        x = post.info.pop(2)
+        y = post.info.pop()
+        self.assertEqual(post.info, ['0', '1', '3', '4'])
+        self.assertEqual(x, '2')
+        self.assertEqual(y, '5')
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '3', '4'])
+
+        # 'remove'
+        reset_post()
+        post.info.remove('2')
+        self.assertEqual(post.info, ['0', '1', '3', '4', '5'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['0', '1', '3', '4', '5'])
+
+        # 'reverse'
+        reset_post()
+        post.info.reverse()
+        self.assertEqual(post.info, ['5', '4', '3', '2', '1', '0'])
+        post.save()
+        post.reload()
+        self.assertEqual(post.info, ['5', '4', '3', '2', '1', '0'])
+
+        # 'sort': though this operator method does manipulate the list, it is tested in
+        #     the 'test_list_field_lexicograpic_operators' function
+        BlogPost.drop_collection()
+
+    def test_list_field_invalid_operators(self):
+        class BlogPost(Document):
+            ref = StringField()
+            info = ListField(StringField())
+        post = BlogPost()
+        post.ref = "1234"
+        post.info = ['0', '1', '2', '3', '4', '5']
+        # '__hash__'
+        # aka 'hash(list)'
+        # # assert TypeError
+        self.assertRaises(TypeError, lambda: hash(post.info))
+
+    def test_list_field_lexicographic_operators(self):
+        """Ensure that ListField works with standard list operators that do lexigraphic ordering.
+        """
+        class BlogPost(Document):
+            ref = StringField()
+            text_info = ListField(StringField())
+            oid_info = ListField(ObjectIdField())
+            bool_info = ListField(BooleanField())
+        BlogPost.drop_collection()
+
+        blogSmall = BlogPost(ref="small")
+        blogSmall.text_info = ["a", "a", "a"]
+        blogSmall.bool_info = [False, False]
+        blogSmall.save()
+        blogSmall.reload()
+
+        blogLargeA = BlogPost(ref="big")
+        blogLargeA.text_info = ["a", "z", "j"]
+        blogLargeA.bool_info = [False, True]
+        blogLargeA.save()
+        blogLargeA.reload()
+
+        blogLargeB = BlogPost(ref="big2")
+        blogLargeB.text_info = ["a", "z", "j"]
+        blogLargeB.oid_info = [
+            "54495ad94c934721ede76f90",
+            "54495ad94c934721ede76d23",
+            "54495ad94c934721ede76d00"
+        ]
+        blogLargeB.bool_info = [False, True]
+        blogLargeB.save()
+        blogLargeB.reload()
+        # '__eq__' aka '=='
+        self.assertEqual(blogLargeA.text_info, blogLargeB.text_info)
+        self.assertEqual(blogLargeA.bool_info, blogLargeB.bool_info)
+        # '__ge__' aka '>='
+        self.assertGreaterEqual(blogLargeA.text_info, blogSmall.text_info)
+        self.assertGreaterEqual(blogLargeA.text_info, blogLargeB.text_info)
+        self.assertGreaterEqual(blogLargeA.bool_info, blogSmall.bool_info)
+        self.assertGreaterEqual(blogLargeA.bool_info, blogLargeB.bool_info)
+        # '__gt__' aka '>'
+        self.assertGreaterEqual(blogLargeA.text_info, blogSmall.text_info)
+        self.assertGreaterEqual(blogLargeA.bool_info, blogSmall.bool_info)
+        # '__le__' aka '<='
+        self.assertLessEqual(blogSmall.text_info, blogLargeB.text_info)
+        self.assertLessEqual(blogLargeA.text_info, blogLargeB.text_info)
+        self.assertLessEqual(blogSmall.bool_info, blogLargeB.bool_info)
+        self.assertLessEqual(blogLargeA.bool_info, blogLargeB.bool_info)
+        # '__lt__' aka '<'
+        self.assertLess(blogSmall.text_info, blogLargeB.text_info)
+        self.assertLess(blogSmall.bool_info, blogLargeB.bool_info)
+        # '__ne__' aka '!='
+        self.assertNotEqual(blogSmall.text_info, blogLargeB.text_info)
+        self.assertNotEqual(blogSmall.bool_info, blogLargeB.bool_info)
+        # 'sort'
+        blogLargeB.bool_info = [True, False, True, False]
+        blogLargeB.text_info.sort()
+        blogLargeB.oid_info.sort()
+        blogLargeB.bool_info.sort()
+        sorted_target_list = [
+            ObjectId("54495ad94c934721ede76d00"),
+            ObjectId("54495ad94c934721ede76d23"),
+            ObjectId("54495ad94c934721ede76f90")
+        ]
+        self.assertEqual(blogLargeB.text_info, ["a", "j", "z"])
+        self.assertEqual(blogLargeB.oid_info, sorted_target_list)
+        self.assertEqual(blogLargeB.bool_info, [False, False, True, True])
+        blogLargeB.save()
+        blogLargeB.reload()
+        self.assertEqual(blogLargeB.text_info, ["a", "j", "z"])
+        self.assertEqual(blogLargeB.oid_info, sorted_target_list)
+        self.assertEqual(blogLargeB.bool_info, [False, False, True, True])
+
         BlogPost.drop_collection()
 
     def test_list_assignment(self):
@@ -1102,7 +1376,6 @@ class FieldTest(unittest.TestCase):
         post.reload()
         self.assertEqual(post.info, [1, 2, 3, 4, 'n5'])
 
-
     def test_list_field_passed_in_value(self):
         class Foo(Document):
             bars = ListField(ReferenceField("Bar"))
@@ -1725,7 +1998,7 @@ class FieldTest(unittest.TestCase):
         self.assertEqual(content, User.objects.first().groups[0].content)
 
     def test_reference_miss(self):
-        """Ensure an exception is raised when dereferencing unknow document
+        """Ensure an exception is raised when dereferencing unknown document
         """
 
         class Foo(Document):
@@ -2926,26 +3199,42 @@ class FieldTest(unittest.TestCase):
         att.delete()
         self.assertEqual(0, Attachment.objects.count())
 
-    def test_choices_validation(self):
-        """Ensure that value is in a container of allowed values.
+    def test_choices_allow_using_sets_as_choices(self):
+        """Ensure that sets can be used when setting choices
         """
         class Shirt(Document):
-            size = StringField(max_length=3, choices=(
-                ('S', 'Small'), ('M', 'Medium'), ('L', 'Large'),
-                ('XL', 'Extra Large'), ('XXL', 'Extra Extra Large')))
+            size = StringField(choices={'M', 'L'})
 
-        Shirt.drop_collection()
+        Shirt(size='M').validate()
+
+    def test_choices_validation_allow_no_value(self):
+        """Ensure that .validate passes and no value was provided
+        for a field setup with choices
+        """
+        class Shirt(Document):
+            size = StringField(choices=('S', 'M'))
 
         shirt = Shirt()
         shirt.validate()
 
-        shirt.size = "S"
+    def test_choices_validation_accept_possible_value(self):
+        """Ensure that value is in a container of allowed values.
+        """
+        class Shirt(Document):
+            size = StringField(choices=('S', 'M'))
+
+        shirt = Shirt(size='S')
         shirt.validate()
 
-        shirt.size = "XS"
-        self.assertRaises(ValidationError, shirt.validate)
+    def test_choices_validation_reject_unknown_value(self):
+        """Ensure that unallowed value are rejected upon validation
+        """
+        class Shirt(Document):
+            size = StringField(choices=('S', 'M'))
 
-        Shirt.drop_collection()
+        shirt = Shirt(size="XS")
+        with self.assertRaises(ValidationError):
+            shirt.validate()
 
     def test_choices_validation_documents(self):
         """
@@ -3731,30 +4020,25 @@ class FieldTest(unittest.TestCase):
         """Tests if a `FieldDoesNotExist` exception is raised when trying to
         instanciate a document with a field that's not defined.
         """
-
         class Doc(Document):
-            foo = StringField(db_field='f')
+            foo = StringField()
 
-        def test():
+        with self.assertRaises(FieldDoesNotExist):
             Doc(bar='test')
 
-        self.assertRaises(FieldDoesNotExist, test)
 
     def test_undefined_field_exception_with_strict(self):
         """Tests if a `FieldDoesNotExist` exception is raised when trying to
         instanciate a document with a field that's not defined,
         even when strict is set to False.
         """
-
         class Doc(Document):
-            foo = StringField(db_field='f')
+            foo = StringField()
             meta = {'strict': False}
 
-        def test():
+        with self.assertRaises(FieldDoesNotExist):
             Doc(bar='test')
 
-        self.assertRaises(FieldDoesNotExist, test)
-
     def test_long_field_is_considered_as_int64(self):
         """
         Tests that long fields are stored as long in mongo, even if long value
@@ -3769,12 +4053,13 @@ class FieldTest(unittest.TestCase):
         self.assertTrue(isinstance(doc.some_long, six.integer_types))
 
 
-class EmbeddedDocumentListFieldTestCase(unittest.TestCase):
-
-    @classmethod
-    def setUpClass(cls):
-        cls.db = connect(db='EmbeddedDocumentListFieldTestCase')
+class EmbeddedDocumentListFieldTestCase(MongoDBTestCase):
 
+    def setUp(self):
+        """
+        Create two BlogPost entries in the database, each with
+        several EmbeddedDocuments.
+        """
         class Comments(EmbeddedDocument):
             author = StringField()
             message = StringField()
@@ -3782,14 +4067,11 @@ class EmbeddedDocumentListFieldTestCase(unittest.TestCase):
         class BlogPost(Document):
             comments = EmbeddedDocumentListField(Comments)
 
-        cls.Comments = Comments
-        cls.BlogPost = BlogPost
+        BlogPost.drop_collection()
+
+        self.Comments = Comments
+        self.BlogPost = BlogPost
 
-    def setUp(self):
-        """
-        Create two BlogPost entries in the database, each with
-        several EmbeddedDocuments.
-        """
         self.post1 = self.BlogPost(comments=[
             self.Comments(author='user1', message='message1'),
             self.Comments(author='user2', message='message1')
@@ -3801,13 +4083,6 @@ class EmbeddedDocumentListFieldTestCase(unittest.TestCase):
             self.Comments(author='user3', message='message1')
         ]).save()
 
-    def tearDown(self):
-        self.BlogPost.drop_collection()
-
-    @classmethod
-    def tearDownClass(cls):
-        cls.db.drop_database('EmbeddedDocumentListFieldTestCase')
-
     def test_no_keyword_filter(self):
         """
         Tests the filter method of a List of Embedded Documents
@@ -4165,7 +4440,8 @@ class EmbeddedDocumentListFieldTestCase(unittest.TestCase):
             my_list = ListField(EmbeddedDocumentField(EmbeddedWithUnique))
 
         A(my_list=[]).save()
-        self.assertRaises(NotUniqueError, lambda: A(my_list=[]).save())
+        with self.assertRaises(NotUniqueError):
+            A(my_list=[]).save()
 
         class EmbeddedWithSparseUnique(EmbeddedDocument):
             number = IntField(unique=True, sparse=True)
@@ -4173,6 +4449,9 @@ class EmbeddedDocumentListFieldTestCase(unittest.TestCase):
         class B(Document):
             my_list = ListField(EmbeddedDocumentField(EmbeddedWithSparseUnique))
 
+        A.drop_collection()
+        B.drop_collection()
+
         B(my_list=[]).save()
         B(my_list=[]).save()
 
@@ -4212,6 +4491,8 @@ class EmbeddedDocumentListFieldTestCase(unittest.TestCase):
             a_field = IntField()
             c_field = IntField(custom_data=custom_data)
 
+        CustomData.drop_collection()
+
         a1 = CustomData(a_field=1, c_field=2).save()
         self.assertEqual(2, a1.c_field)
         self.assertFalse(hasattr(a1.c_field, 'custom_data'))

tests/fields/file_tests.py

@@ -18,15 +18,13 @@ try:
 except ImportError:
     HAS_PIL = False
 
+from tests.utils import MongoDBTestCase
+
 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')
 
 
-class FileTest(unittest.TestCase):
-
-    def setUp(self):
-        connect(db='mongoenginetest')
-        self.db = get_db()
+class FileTest(MongoDBTestCase):
 
     def tearDown(self):
         self.db.drop_collection('fs.files')

tests/queryset/field_list.py

@@ -141,6 +141,16 @@ class OnlyExcludeAllTest(unittest.TestCase):
         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.
         """

tests/queryset/queryset.py

@@ -106,58 +106,111 @@ class QuerySetTest(unittest.TestCase):
             list(BlogPost.objects(author2__name="test"))
 
     def test_find(self):
-        """Ensure that a query returns a valid set of results.
-        """
-        self.Person(name="User A", age=20).save()
-        self.Person(name="User B", age=30).save()
+        """Ensure that a query returns a valid set of results."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
 
         # Find all people in the collection
         people = self.Person.objects
         self.assertEqual(people.count(), 2)
         results = list(people)
+
         self.assertTrue(isinstance(results[0], self.Person))
         self.assertTrue(isinstance(results[0].id, (ObjectId, str, unicode)))
-        self.assertEqual(results[0].name, "User A")
+
+        self.assertEqual(results[0], user_a)
+        self.assertEqual(results[0].name, 'User A')
         self.assertEqual(results[0].age, 20)
-        self.assertEqual(results[1].name, "User B")
+
+        self.assertEqual(results[1], user_b)
+        self.assertEqual(results[1].name, 'User B')
         self.assertEqual(results[1].age, 30)
 
-        # Use a query to filter the people found to just person1
+        # Filter people by age
         people = self.Person.objects(age=20)
         self.assertEqual(people.count(), 1)
         person = people.next()
+        self.assertEqual(person, user_a)
         self.assertEqual(person.name, "User A")
         self.assertEqual(person.age, 20)
 
-        # Test limit
+    def test_limit(self):
+        """Ensure that QuerySet.limit works as expected."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
+
+        # Test limit on a new queryset
         people = list(self.Person.objects.limit(1))
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0].name, 'User A')
+        self.assertEqual(people[0], user_a)
 
-        # Test skip
+        # Test limit on an existing queryset
+        people = self.Person.objects
+        self.assertEqual(len(people), 2)
+        people2 = people.limit(1)
+        self.assertEqual(len(people), 2)
+        self.assertEqual(len(people2), 1)
+        self.assertEqual(people2[0], user_a)
+
+        # Test chaining of only after limit
+        person = self.Person.objects().limit(1).only('name').first()
+        self.assertEqual(person, user_a)
+        self.assertEqual(person.name, 'User A')
+        self.assertEqual(person.age, None)
+
+    def test_skip(self):
+        """Ensure that QuerySet.skip works as expected."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
+
+        # Test skip on a new queryset
         people = list(self.Person.objects.skip(1))
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0].name, 'User B')
+        self.assertEqual(people[0], user_b)
 
-        person3 = self.Person(name="User C", age=40)
-        person3.save()
+        # Test skip on an existing queryset
+        people = self.Person.objects
+        self.assertEqual(len(people), 2)
+        people2 = people.skip(1)
+        self.assertEqual(len(people), 2)
+        self.assertEqual(len(people2), 1)
+        self.assertEqual(people2[0], user_b)
+
+        # Test chaining of only after skip
+        person = self.Person.objects().skip(1).only('name').first()
+        self.assertEqual(person, user_b)
+        self.assertEqual(person.name, 'User B')
+        self.assertEqual(person.age, None)
+
+    def test_slice(self):
+        """Ensure slicing a queryset works as expected."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
+        user_c = self.Person.objects.create(name="User C", age=40)
 
         # Test slice limit
         people = list(self.Person.objects[:2])
         self.assertEqual(len(people), 2)
-        self.assertEqual(people[0].name, 'User A')
-        self.assertEqual(people[1].name, 'User B')
+        self.assertEqual(people[0], user_a)
+        self.assertEqual(people[1], user_b)
 
         # Test slice skip
         people = list(self.Person.objects[1:])
         self.assertEqual(len(people), 2)
-        self.assertEqual(people[0].name, 'User B')
-        self.assertEqual(people[1].name, 'User C')
+        self.assertEqual(people[0], user_b)
+        self.assertEqual(people[1], user_c)
 
         # Test slice limit and skip
         people = list(self.Person.objects[1:2])
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0].name, 'User B')
+        self.assertEqual(people[0], user_b)
+
+        # Test slice limit and skip on an existing queryset
+        people = self.Person.objects
+        self.assertEqual(len(people), 3)
+        people2 = people[1:2]
+        self.assertEqual(len(people2), 1)
+        self.assertEqual(people2[0], user_b)
 
         # Test slice limit and skip cursor reset
         qs = self.Person.objects[1:2]
@@ -168,6 +221,7 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual(len(people), 1)
         self.assertEqual(people[0].name, 'User B')
 
+        # Test empty slice
         people = list(self.Person.objects[1:1])
         self.assertEqual(len(people), 0)
 
@@ -187,12 +241,6 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual("[<Person: Person object>, <Person: Person object>]",
                          "%s" % self.Person.objects[51:53])
 
-        # Test only after limit
-        self.assertEqual(self.Person.objects().limit(2).only('name')[0].age, None)
-
-        # Test only after skip
-        self.assertEqual(self.Person.objects().skip(2).only('name')[0].age, None)
-
     def test_find_one(self):
         """Ensure that a query using find_one returns a valid result.
         """
@@ -1226,6 +1274,7 @@ class QuerySetTest(unittest.TestCase):
 
         BlogPost.drop_collection()
 
+        # default ordering should be used by default
         with db_ops_tracker() as q:
             BlogPost.objects.filter(title='whatever').first()
             self.assertEqual(len(q.get_ops()), 1)
@@ -1234,11 +1283,28 @@ class QuerySetTest(unittest.TestCase):
                 {'published_date': -1}
             )
 
+        # calling order_by() should clear the default ordering
         with db_ops_tracker() as q:
             BlogPost.objects.filter(title='whatever').order_by().first()
             self.assertEqual(len(q.get_ops()), 1)
             self.assertFalse('$orderby' in q.get_ops()[0]['query'])
 
+        # calling an explicit order_by should use a specified sort
+        with db_ops_tracker() as q:
+            BlogPost.objects.filter(title='whatever').order_by('published_date').first()
+            self.assertEqual(len(q.get_ops()), 1)
+            self.assertEqual(
+                q.get_ops()[0]['query']['$orderby'],
+                {'published_date': 1}
+            )
+
+        # calling order_by() after an explicit sort should clear it
+        with db_ops_tracker() as q:
+            qs = BlogPost.objects.filter(title='whatever').order_by('published_date')
+            qs.order_by().first()
+            self.assertEqual(len(q.get_ops()), 1)
+            self.assertFalse('$orderby' in q.get_ops()[0]['query'])
+
     def test_no_ordering_for_get(self):
         """ Ensure that Doc.objects.get doesn't use any ordering.
         """
@@ -1266,7 +1332,7 @@ class QuerySetTest(unittest.TestCase):
 
     def test_find_embedded(self):
         """Ensure that an embedded document is properly returned from
-        a query.
+        different manners of querying.
         """
         class User(EmbeddedDocument):
             name = StringField()
@@ -1277,8 +1343,9 @@ class QuerySetTest(unittest.TestCase):
 
         BlogPost.drop_collection()
 
+        user = User(name='Test User')
         BlogPost.objects.create(
-            author=User(name='Test User'),
+            author=user,
             content='Had a good coffee today...'
         )
 
@@ -1286,6 +1353,19 @@ class QuerySetTest(unittest.TestCase):
         self.assertTrue(isinstance(result.author, User))
         self.assertEqual(result.author.name, 'Test User')
 
+        result = BlogPost.objects.get(author__name=user.name)
+        self.assertTrue(isinstance(result.author, User))
+        self.assertEqual(result.author.name, 'Test User')
+
+        result = BlogPost.objects.get(author={'name': user.name})
+        self.assertTrue(isinstance(result.author, User))
+        self.assertEqual(result.author.name, 'Test User')
+
+        # Fails, since the string is not a type that is able to represent the
+        # author's document structure (should be dict)
+        with self.assertRaises(InvalidQueryError):
+            BlogPost.objects.get(author=user.name)
+
     def test_find_empty_embedded(self):
         """Ensure that you can save and find an empty embedded document."""
         class User(EmbeddedDocument):
@@ -1812,6 +1892,11 @@ class QuerySetTest(unittest.TestCase):
         post.reload()
         self.assertEqual(post.hits, 10)
 
+        # Negative dec operator is equal to a positive inc operator
+        BlogPost.objects.update_one(dec__hits=-1)
+        post.reload()
+        self.assertEqual(post.hits, 11)
+
         BlogPost.objects.update(push__tags='mongo')
         post.reload()
         self.assertTrue('mongo' in post.tags)
@@ -4963,6 +5048,35 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual(i, 249)
         self.assertEqual(j, 249)
 
+    def test_in_operator_on_non_iterable(self):
+        """Ensure that using the `__in` operator on a non-iterable raises an
+        error.
+        """
+        class User(Document):
+            name = StringField()
+
+        class BlogPost(Document):
+            content = StringField()
+            authors = ListField(ReferenceField(User))
+
+        User.drop_collection()
+        BlogPost.drop_collection()
+
+        author = User.objects.create(name='Test User')
+        post = BlogPost.objects.create(content='Had a good coffee today...',
+                                       authors=[author])
+
+        # Make sure using `__in` with a list works
+        blog_posts = BlogPost.objects(authors__in=[author])
+        self.assertEqual(list(blog_posts), [post])
+
+        # Using `__in` with a non-iterable should raise a TypeError
+        self.assertRaises(TypeError, BlogPost.objects(authors__in=author.pk).count)
+
+        # Using `__in` with a `Document` (which is seemingly iterable but not
+        # in a way we'd expect) should raise a TypeError, too
+        self.assertRaises(TypeError, BlogPost.objects(authors__in=author).count)
+
 
 if __name__ == '__main__':
     unittest.main()

tests/test_connection.py

@@ -200,6 +200,19 @@ class ConnectionTest(unittest.TestCase):
         self.assertTrue(isinstance(db, pymongo.database.Database))
         self.assertEqual(db.name, 'test')
 
+    def test_connect_uri_with_replicaset(self):
+        """Ensure connect() works when specifying a replicaSet."""
+        if IS_PYMONGO_3:
+            c = connect(host='mongodb://localhost/test?replicaSet=local-rs')
+            db = get_db()
+            self.assertTrue(isinstance(db, pymongo.database.Database))
+            self.assertEqual(db.name, 'test')
+        else:
+            # PyMongo < v3.x raises an exception:
+            # "localhost:27017 is not a member of replica set local-rs"
+            with self.assertRaises(MongoEngineConnectionError):
+                c = connect(host='mongodb://localhost/test?replicaSet=local-rs')
+
     def test_uri_without_credentials_doesnt_override_conn_settings(self):
         """Ensure connect() uses the username & password params if the URI
         doesn't explicitly specify them.
@@ -272,8 +285,7 @@ class ConnectionTest(unittest.TestCase):
         self.assertTrue(isinstance(conn, pymongo.mongo_client.MongoClient))
 
     def test_connection_kwargs(self):
-        """Ensure that connection kwargs get passed to pymongo.
-        """
+        """Ensure that connection kwargs get passed to pymongo."""
         connect('mongoenginetest', alias='t1', tz_aware=True)
         conn = get_connection('t1')
 
@@ -283,6 +295,45 @@ class ConnectionTest(unittest.TestCase):
         conn = get_connection('t2')
         self.assertFalse(get_tz_awareness(conn))
 
+    def test_connection_pool_via_kwarg(self):
+        """Ensure we can specify a max connection pool size using
+        a connection kwarg.
+        """
+        # Use "max_pool_size" or "maxpoolsize" depending on PyMongo version
+        # (former was changed to the latter as described in
+        # https://jira.mongodb.org/browse/PYTHON-854).
+        # TODO remove once PyMongo < 3.0 support is dropped
+        if pymongo.version_tuple[0] >= 3:
+            pool_size_kwargs = {'maxpoolsize': 100}
+        else:
+            pool_size_kwargs = {'max_pool_size': 100}
+
+        conn = connect('mongoenginetest', alias='max_pool_size_via_kwarg', **pool_size_kwargs)
+        self.assertEqual(conn.max_pool_size, 100)
+
+    def test_connection_pool_via_uri(self):
+        """Ensure we can specify a max connection pool size using
+        an option in a connection URI.
+        """
+        if pymongo.version_tuple[0] == 2 and pymongo.version_tuple[1] < 9:
+            raise SkipTest('maxpoolsize as a URI option is only supported in PyMongo v2.9+')
+
+        conn = connect(host='mongodb://localhost/test?maxpoolsize=100', alias='max_pool_size_via_uri')
+        self.assertEqual(conn.max_pool_size, 100)
+
+    def test_write_concern(self):
+        """Ensure write concern can be specified in connect() via
+        a kwarg or as part of the connection URI.
+        """
+        conn1 = connect(alias='conn1', host='mongodb://localhost/testing?w=1&j=true')
+        conn2 = connect('testing', alias='conn2', w=1, j=True)
+        if IS_PYMONGO_3:
+            self.assertEqual(conn1.write_concern.document, {'w': 1, 'j': True})
+            self.assertEqual(conn2.write_concern.document, {'w': 1, 'j': True})
+        else:
+            self.assertEqual(dict(conn1.write_concern), {'w': 1, 'j': True})
+            self.assertEqual(dict(conn2.write_concern), {'w': 1, 'j': True})
+
     def test_datetime(self):
         connect('mongoenginetest', tz_aware=True)
         d = datetime.datetime(2010, 5, 5, tzinfo=utc)

tests/utils.py

@@ -0,0 +1,22 @@
+import unittest
+
+from mongoengine import connect
+from mongoengine.connection import get_db
+
+MONGO_TEST_DB = 'mongoenginetest'
+
+
+class MongoDBTestCase(unittest.TestCase):
+    """Base class for tests that need a mongodb connection
+    db is being dropped automatically
+    """
+
+    @classmethod
+    def setUpClass(cls):
+        cls._connection = connect(db=MONGO_TEST_DB)
+        cls._connection.drop_database(MONGO_TEST_DB)
+        cls.db = get_db()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls._connection.drop_database(MONGO_TEST_DB)