Merge remote branch 'hmarr/master'
Conflicts: mongoengine/queryset.py
This commit is contained in:
Florian Schlachter
commit
963a223e7e
@ -86,6 +86,41 @@ achieving this is using array-slicing syntax::
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# 5 users, starting from the 10th user found
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users = User.objects[10:15]
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You may also index the query to retrieve a single result. If an item at that
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index does not exists, an :class:`IndexError` will be raised. A shortcut for
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retrieving the first result and returning :attr:`None` if no result exists is
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provided (:meth:`~mongoengine.queryset.QuerySet.first`)::
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>>> # Make sure there are no users
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>>> User.drop_collection()
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>>> User.objects[0]
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IndexError: list index out of range
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>>> User.objects.first() == None
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True
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>>> User(name='Test User').save()
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>>> User.objects[0] == User.objects.first()
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True
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Retrieving unique results
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-------------------------
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To retrieve a result that should be unique in the collection, use
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:meth:`~mongoengine.queryset.QuerySet.get`. This will raise
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:class:`~mongoengine.queryset.DoesNotExist` if no document matches the query,
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and :class:`~mongoengine.queryset.MultipleObjectsReturned` if more than one
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document matched the query.
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A variation of this method exists,
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:meth:`~mongoengine.queryset.Queryset.get_or_create`, that will create a new
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document with the query arguments if no documents match the query. An
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additional keyword argument, :attr:`defaults` may be provided, which will be
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used as default values for the new document, in the case that it should need
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to be created::
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>>> a = User.objects.get_or_create(name='User A', defaults={'age': 30})
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>>> b = User.objects.get_or_create(name='User A', defaults={'age': 40})
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>>> a.name == b.name and a.age == b.age
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True
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Default Document queries
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========================
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By default, the objects :attr:`~mongoengine.Document.objects` attribute on a
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@ -11,6 +11,11 @@ MongoDB. To install it, simply run
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The source is available on `GitHub <http://github.com/hmarr/mongoengine>`_.
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If you are interested in contributing, join the developers' `mailing list
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<http://groups.google.com/group/mongoengine-dev>`_. Some of us also like to
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hang out at `#mongoengine IRC channel <irc://irc.freenode.net/mongoengine>`_.
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.. toctree::
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:maxdepth: 2
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@ -352,19 +352,15 @@ class BaseDocument(object):
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if value is not None:
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data[field.name] = field.to_mongo(value)
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# Only add _cls and _types if allow_inheritance is not False
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#if not (hasattr(self, '_meta') and
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# self._meta.get('allow_inheritance', True) == False):
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ah = True
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if hasattr(self, '_meta'):
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ah = self._meta.get('allow_inheritance', True)
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if ah:
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if not (hasattr(self, '_meta') and
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self._meta.get('allow_inheritance', True) == False):
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data['_cls'] = self._class_name
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data['_types'] = self._superclasses.keys() + [self._class_name]
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return data
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@classmethod
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def _from_son(cls, son):
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"""Create an instance of a Document (subclass) from a PyMongo SOM.
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"""Create an instance of a Document (subclass) from a PyMongo SON.
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"""
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# get the class name from the document, falling back to the given
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# class if unavailable
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@ -10,6 +10,7 @@ __all__ = ['queryset_manager', 'Q', 'InvalidQueryError',
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# The maximum number of items to display in a QuerySet.__repr__
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REPR_OUTPUT_SIZE = 20
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class DoesNotExist(Exception):
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pass
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@ -299,37 +300,46 @@ class QuerySet(object):
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return mongo_query
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def get_or_create(self, **kwargs):
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"""Retreive unique object or create, if it doesn't exist
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def get(self, *q_objs, **query):
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"""Retrieve the the matching object raising
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:class:`~mongoengine.queryset.MultipleObjectsReturned` or
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:class:`~mongoengine.queryset.DoesNotExist` exceptions if multiple or
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no results are found.
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"""
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defaults = kwargs.get('defaults', {})
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if kwargs.has_key('defaults'):
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del kwargs['defaults']
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dataset = self.filter(**kwargs)
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cnt = dataset.count()
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if cnt == 0:
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kwargs.update(defaults)
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doc = self._document(**kwargs)
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doc.save()
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return doc
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elif cnt == 1:
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return dataset.first()
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else:
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raise MultipleObjectsReturned(u'%d items returned, expected exactly one' % cnt)
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def get(self, **kwargs):
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"""Retreive exactly one document. Raise DoesNotExist if it's not found.
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"""
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dataset = self.filter(**kwargs)
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cnt = dataset.count()
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if cnt == 1:
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return dataset.first()
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elif cnt > 1:
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raise MultipleObjectsReturned(u'%d items returned, expected exactly one' % cnt)
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self.__call__(*q_objs, **query)
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count = self.count()
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if count == 1:
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return self[0]
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elif count > 1:
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message = u'%d items returned, instead of 1' % count
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raise MultipleObjectsReturned(message)
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else:
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raise DoesNotExist('Document not found')
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def get_or_create(self, *q_objs, **query):
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"""Retreive unique object or create, if it doesn't exist. Raises
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:class:`~mongoengine.queryset.MultipleObjectsReturned` if multiple
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results are found. A new document will be created if the document
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doesn't exists; a dictionary of default values for the new document
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may be provided as a keyword argument called :attr:`defaults`.
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"""
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defaults = query.get('defaults', {})
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if query.has_key('defaults'):
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del query['defaults']
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self.__call__(*q_objs, **query)
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count = self.count()
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if count == 0:
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query.update(defaults)
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doc = self._document(**query)
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doc.save()
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return doc
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elif count == 1:
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return self.first()
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else:
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message = u'%d items returned, instead of 1' % count
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raise MultipleObjectsReturned(message)
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def first(self):
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"""Retrieve the first object matching the query.
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"""
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@ -2,7 +2,8 @@ import unittest
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import pymongo
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from datetime import datetime
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from mongoengine.queryset import QuerySet
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from mongoengine.queryset import (QuerySet, MultipleObjectsReturned,
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DoesNotExist)
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from mongoengine import *
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@ -135,6 +136,54 @@ class QuerySetTest(unittest.TestCase):
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person = self.Person.objects.with_id(person1.id)
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self.assertEqual(person.name, "User A")
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def test_find_only_one(self):
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"""Ensure that a query using ``get`` returns at most one result.
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"""
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# Try retrieving when no objects exists
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self.assertRaises(DoesNotExist, self.Person.objects.get)
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person1 = self.Person(name="User A", age=20)
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person1.save()
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person2 = self.Person(name="User B", age=30)
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person2.save()
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# Retrieve the first person from the database
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self.assertRaises(MultipleObjectsReturned, self.Person.objects.get)
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# Use a query to filter the people found to just person2
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person = self.Person.objects.get(age=30)
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self.assertEqual(person.name, "User B")
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person = self.Person.objects.get(age__lt=30)
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self.assertEqual(person.name, "User A")
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def test_get_or_create(self):
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"""Ensure that ``get_or_create`` returns one result or creates a new
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document.
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"""
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person1 = self.Person(name="User A", age=20)
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person1.save()
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person2 = self.Person(name="User B", age=30)
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person2.save()
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# Retrieve the first person from the database
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self.assertRaises(MultipleObjectsReturned,
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self.Person.objects.get_or_create)
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# Use a query to filter the people found to just person2
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person = self.Person.objects.get_or_create(age=30)
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self.assertEqual(person.name, "User B")
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person = self.Person.objects.get_or_create(age__lt=30)
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self.assertEqual(person.name, "User A")
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# Try retrieving when no objects exists - new doc should be created
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self.Person.objects.get_or_create(age=50, defaults={'name': 'User C'})
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person = self.Person.objects.get(age=50)
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self.assertEqual(person.name, "User C")
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def test_filter_chaining(self):
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"""Ensure filters can be chained together.
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"""
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