cleaner Document._save_update

README.rst

@@ -35,22 +35,16 @@ setup.py install``.
 
 Dependencies
 ============
-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
+- sphinx (optional - for documentation generation)
-
-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
 
-If you need to use an ``ImageField`` or ``ImageGridFsProxy``:
+.. note
-
+   MongoEngine always runs it's test suite against the latest patch version of each dependecy. e.g.: PyMongo 3.0.1
-- Pillow>=2.0.0
-
-If you want to generate the documentation (e.g. to contribute to it):
-
-- sphinx
 
 Examples
 ========

docs/changelog.rst

@@ -5,8 +5,6 @@ Changelog
 Development
 ===========
 - (Fill this out as you fix issues and develop you features).
-- 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
 
@@ -15,7 +13,6 @@ 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/defining-documents.rst

@@ -361,6 +361,11 @@ 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/signals.rst

@@ -142,4 +142,11 @@ 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

@@ -2,20 +2,6 @@
 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/datastructures.py

@@ -429,7 +429,7 @@ class StrictDict(object):
     def __eq__(self, other):
         return self.items() == other.items()
 
-    def __ne__(self, other):
+    def __neq__(self, other):
         return self.items() != other.items()
 
     @classmethod

mongoengine/base/fields.py

@@ -189,18 +189,14 @@ class BaseField(object):
         pass
 
     def _validate_choices(self, value):
-        """Validate that value is a valid choice for this field."""
         Document = _import_class('Document')
         EmbeddedDocument = _import_class('EmbeddedDocument')
 
-        # Field choices can be given as an iterable (e.g. tuple/list/set) of
-        # values or an iterable of value-label pairs, e.g. ('XS', 'Extra Small').
-        # It the latter case, extract just the values for comparison.
         choice_list = self.choices
-        if isinstance(next(iter(choice_list)), (list, tuple)):
+        if isinstance(choice_list[0], (list, tuple)):
-            choice_list = [val for val, label in choice_list]
+            choice_list = [k for k, _ in choice_list]
 
-        # Validate Document/EmbeddedDocument choices
+        # 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(
@@ -208,8 +204,7 @@ class BaseField(object):
                         six.text_type(choice_list)
                     )
                 )
-
+        # Choices which are types other than Documents
-        # Validate any other type of choices
         elif value not in choice_list:
             self.error('Value must be one of %s' % six.text_type(choice_list))
 

mongoengine/errors.py

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

mongoengine/fields.py

@@ -888,6 +888,10 @@ 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

@@ -86,7 +86,6 @@ 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):
@@ -707,36 +706,39 @@ 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):
-        """Create a copy of the current queryset."""
+        """Creates a copy of the current
-        return self._clone_into(self.__class__(self._document, self._collection_obj))
+          :class:`~mongoengine.queryset.QuerySet`
 
-    def _clone_into(self, new_qs):
+        .. versionadded:: 0.5
-        """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`).
         """
-        if not isinstance(new_qs, 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):
             raise OperationError(
-                '%s is not a subclass of BaseQuerySet' % new_qs.__name__)
+                '%s is not a subclass of BaseQuerySet' % cls.__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', '_comment')
+                      '_search_text', 'only_fields', '_max_time_ms')
 
         for prop in copy_props:
             val = getattr(self, prop)
-            setattr(new_qs, prop, copy.copy(val))
+            setattr(cls, prop, copy.copy(val))
 
         if self._cursor_obj:
-            new_qs._cursor_obj = self._cursor_obj.clone()
+            cls._cursor_obj = self._cursor_obj.clone()
 
-        return new_qs
+        return cls
 
     def select_related(self, max_depth=1):
         """Handles dereferencing of :class:`~bson.dbref.DBRef` objects or
@@ -758,11 +760,7 @@ 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):
@@ -773,11 +771,6 @@ 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):
@@ -795,11 +788,6 @@ 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):
@@ -813,11 +801,6 @@ 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):
@@ -989,31 +972,13 @@ 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. If no keys are passed, existing ordering
+        Ascending order is assumed.
-        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):
@@ -1459,13 +1424,10 @@ 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,
-        doc = self._document._from_son(
+                                       _auto_dereference=self._auto_dereference, only_fields=self.only_fields)
-            raw_doc, _auto_dereference=self._auto_dereference,
-            only_fields=self.only_fields)
 
         if self._scalar:
             return self._get_scalar(doc)
@@ -1475,6 +1437,7 @@ class BaseQuerySet(object):
     def rewind(self):
         """Rewind the cursor to its unevaluated state.
 
+
         .. versionadded:: 0.3
         """
         self._iter = False
@@ -1524,54 +1487,43 @@ class BaseQuerySet(object):
 
     @property
     def _cursor(self):
-        """Return a PyMongo cursor object corresponding to this queryset."""
+        if self._cursor_obj is None:
 
-        # If _cursor_obj already exists, return it immediately.
+            # In PyMongo 3+, we define the read preference on a collection
-        if self._cursor_obj is not None:
+            # level, not a cursor level. Thus, we need to get a cloned
-            return self._cursor_obj
+            # 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)
 
-        # Create a new PyMongo cursor.
+            if self._ordering:
-        # XXX In PyMongo 3+, we define the read preference on a collection
+                # Apply query ordering
-        # level, not a cursor level. Thus, we need to get a cloned collection
+                self._cursor_obj.sort(self._ordering)
-        # object using `with_options` first.
+            elif self._ordering is None and self._document._meta['ordering']:
-        if IS_PYMONGO_3 and self._read_preference is not None:
+                # Otherwise, apply the ordering from the document model, unless
-            self._cursor_obj = self._collection\
+                # it's been explicitly cleared via order_by with no arguments
-                .with_options(read_preference=self._read_preference)\
+                order = self._get_order_by(self._document._meta['ordering'])
-                .find(self._query, **self._cursor_args)
+                self._cursor_obj.sort(order)
-        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)
 
-        # Apply ordering to the cursor.
+            if self._limit is not None:
-        # XXX self._ordering can be equal to:
+                self._cursor_obj.limit(self._limit)
-        # * 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._limit is not None:
+            if self._skip is not None:
-            self._cursor_obj.limit(self._limit)
+                self._cursor_obj.skip(self._skip)
 
-        if self._skip is not None:
+            if self._hint != -1:
-            self._cursor_obj.skip(self._skip)
+                self._cursor_obj.hint(self._hint)
 
-        if self._hint != -1:
+            if self._batch_size is not None:
-            self._cursor_obj.hint(self._hint)
+                self._cursor_obj.batch_size(self._batch_size)
-
-        if self._batch_size is not None:
-            self._cursor_obj.batch_size(self._batch_size)
 
         return self._cursor_obj
 
@@ -1746,13 +1698,7 @@ class BaseQuerySet(object):
         return ret
 
     def _get_order_by(self, keys):
-        """Given a list of MongoEngine-style sort keys, return a list
+        """Creates a list of order by fields"""
-        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:
@@ -1765,19 +1711,17 @@ 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):
@@ -1875,21 +1819,10 @@ 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)
-        # Get an existing cursor object or create a new one
+        method(val)
-        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

@@ -136,15 +136,13 @@ 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):
@@ -155,7 +153,7 @@ 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

tests/fields/fields.py

@@ -1985,7 +1985,7 @@ 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 unknown document
+        """Ensure an exception is raised when dereferencing unknow document
         """
 
         class Foo(Document):
@@ -3205,22 +3205,8 @@ class FieldTest(unittest.TestCase):
         shirt.size = "XS"
         self.assertRaises(ValidationError, shirt.validate)
 
-    def test_choices_as_set(self):
-        """Ensure that sets can be used as field choices"""
-        class Shirt(Document):
-            size = StringField(choices={'S', 'M', 'L', 'XL', 'XXL'})
-
         Shirt.drop_collection()
 
-        shirt = Shirt()
-        shirt.validate()
-
-        shirt.size = "S"
-        shirt.validate()
-
-        shirt.size = "XS"
-        self.assertRaises(ValidationError, shirt.validate)
-
     def test_choices_validation_documents(self):
         """
         Ensure fields with document choices validate given a valid choice.

tests/queryset/queryset.py

@@ -106,111 +106,58 @@ class QuerySetTest(unittest.TestCase):
             list(BlogPost.objects(author2__name="test"))
 
     def test_find(self):
-        """Ensure that a query returns a valid set of results."""
+        """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)
+        self.Person(name="User A", age=20).save()
+        self.Person(name="User B", age=30).save()
 
         # 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)
 
-        # Filter people by age
+        # Use a query to filter the people found to just person1
         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)
 
-    def test_limit(self):
+        # Test limit
-        """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], user_a)
+        self.assertEqual(people[0].name, 'User A')
 
-        # Test limit on an existing queryset
+        # Test skip
-        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], user_b)
+        self.assertEqual(people[0].name, 'User B')
 
-        # Test skip on an existing queryset
+        person3 = self.Person(name="User C", age=40)
-        people = self.Person.objects
+        person3.save()
-        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], user_a)
+        self.assertEqual(people[0].name, 'User A')
-        self.assertEqual(people[1], user_b)
+        self.assertEqual(people[1].name, 'User B')
 
         # Test slice skip
         people = list(self.Person.objects[1:])
         self.assertEqual(len(people), 2)
-        self.assertEqual(people[0], user_b)
+        self.assertEqual(people[0].name, 'User B')
-        self.assertEqual(people[1], user_c)
+        self.assertEqual(people[1].name, 'User C')
 
         # Test slice limit and skip
         people = list(self.Person.objects[1:2])
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0], user_b)
+        self.assertEqual(people[0].name, '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]
@@ -221,7 +168,6 @@ 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)
 
@@ -241,6 +187,12 @@ 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.
         """
@@ -1274,7 +1226,6 @@ 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)
@@ -1283,28 +1234,11 @@ 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.
         """