factory_boy =========== .. image:: https://secure.travis-ci.org/rbarrois/factory_boy.png?branch=master :target: http://travis-ci.org/rbarrois/factory_boy/ factory_boy is a fixtures replacement based on thoughtbot's `factory_girl `_. As a fixtures replacement tool, it aims to replace static, hard to maintain fixtures with easy-to-use factories for complex object. Instead of building an exhaustive test setup with every possible combination of corner cases, ``factory_boy`` allows you to use objects customized for the current test, while only declaring the test-specific fields: .. code-block:: python class FooTests(unittest.TestCase): def test_with_factory_boy(self): # We need a 200€, paid order, shipping to australia, for a VIP customer order = OrderFactory( amount=200, status='PAID', customer__is_vip=True, address__country='AU', ) # Run the tests here def test_without_factory_boy(self): address = Address( street="42 fubar street", zipcode="42Z42", city="Sydney", country="AU", ) customer = Customer( first_name="John", last_name="Doe", phone="+1234", email="john.doe@example.org", active=True, is_vip=True, address=address, ) # etc. factory_boy is designed to work well with various ORMs (Django, Mogo, SQLAlchemy), and can easily be extended for other libraries. Its main features include: - Straightforward declarative syntax - Chaining factory calls while retaining the global context - Support for multiple build strategies (saved/unsaved instances, attribute dicts, stubbed objects) - Multiple factories per class support, including inheritance Links ----- * Documentation: http://factoryboy.readthedocs.org/ * Repository: https://github.com/rbarrois/factory_boy * Package: https://pypi.python.org/pypi/factory_boy/ factory_boy supports Python 2.6, 2.7, 3.2 and 3.3, as well as PyPy; it requires only the standard Python library. Download -------- PyPI: https://pypi.python.org/pypi/factory_boy/ .. code-block:: sh $ pip install factory_boy Source: https://github.com/rbarrois/factory_boy/ .. code-block:: sh $ git clone git://github.com/rbarrois/factory_boy/ $ python setup.py install Usage ----- .. note:: This section provides a quick summary of factory_boy features. A more detailed listing is available in the full documentation. Defining factories """""""""""""""""" Factories declare a set of attributes used to instantiate an object. The class of the object must be defined in the ``model`` field of a ``class Meta:`` attribute: .. code-block:: python import factory from . import models class UserFactory(factory.Factory): class Meta: model = models.User first_name = 'John' last_name = 'Doe' admin = False # Another, different, factory for the same object class AdminFactory(factory.Factory): class Meta: model = models.User first_name = 'Admin' last_name = 'User' admin = True Using factories """"""""""""""" factory_boy supports several different build strategies: build, create, attributes and stub: .. code-block:: python # Returns a User instance that's not saved user = UserFactory.build() # Returns a saved User instance user = UserFactory.create() # Returns a dict of attributes that can be used to build a User instance attributes = UserFactory.attributes() You can use the Factory class as a shortcut for the default build strategy: .. code-block:: python # Same as UserFactory.create() user = UserFactory() No matter which strategy is used, it's possible to override the defined attributes by passing keyword arguments: .. code-block:: pycon # Build a User instance and override first_name >>> user = UserFactory.build(first_name='Joe') >>> user.first_name "Joe" Lazy Attributes """"""""""""""" Most factory attributes can be added using static values that are evaluated when the factory is defined, but some attributes (such as fields whose value is computed from other elements) will need values assigned each time an instance is generated. These "lazy" attributes can be added as follows: .. code-block:: python class UserFactory(factory.Factory): class Meta: model = models.User first_name = 'Joe' last_name = 'Blow' email = factory.LazyAttribute(lambda a: '{0}.{1}@example.com'.format(a.first_name, a.last_name).lower()) .. code-block:: pycon >>> UserFactory().email "joe.blow@example.com" Sequences """"""""" Unique values in a specific format (for example, e-mail addresses) can be generated using sequences. Sequences are defined by using ``Sequence`` or the decorator ``sequence``: .. code-block:: python class UserFactory(factory.Factory): class Meta: model = models.User email = factory.Sequence(lambda n: 'person{0}@example.com'.format(n)) >>> UserFactory().email 'person0@example.com' >>> UserFactory().email 'person1@example.com' Associations """""""""""" Some objects have a complex field, that should itself be defined from a dedicated factories. This is handled by the ``SubFactory`` helper: .. code-block:: python class PostFactory(factory.Factory): class Meta: model = models.Post author = factory.SubFactory(UserFactory) The associated object's strategy will be used: .. code-block:: python # Builds and saves a User and a Post >>> post = PostFactory() >>> post.id is None # Post has been 'saved' False >>> post.author.id is None # post.author has been saved False # Builds but does not save a User, and then builds but does not save a Post >>> post = PostFactory.build() >>> post.id is None True >>> post.author.id is None True Debugging factory_boy """"""""""""""""""""" Debugging factory_boy can be rather complex due to the long chains of calls. Detailed logging is available through the ``factory`` logger. A helper, :meth:`factory.debug()`, is available to ease debugging: .. code-block:: python with factory.debug(): obj = TestModel2Factory() import logging logger = logging.getLogger('factory') logger.addHandler(logging.StreamHandler()) logger.setLevel(logging.DEBUG) This will yield messages similar to those (artificial indentation): .. code-block:: ini BaseFactory: Preparing tests.test_using.TestModel2Factory(extra={}) LazyStub: Computing values for tests.test_using.TestModel2Factory(two=>) SubFactory: Instantiating tests.test_using.TestModelFactory(__containers=(,), one=4), create=True BaseFactory: Preparing tests.test_using.TestModelFactory(extra={'__containers': (,), 'one': 4}) LazyStub: Computing values for tests.test_using.TestModelFactory(one=4) LazyStub: Computed values, got tests.test_using.TestModelFactory(one=4) BaseFactory: Generating tests.test_using.TestModelFactory(one=4) LazyStub: Computed values, got tests.test_using.TestModel2Factory(two=) BaseFactory: Generating tests.test_using.TestModel2Factory(two=) ORM Support """"""""""" factory_boy has specific support for a few ORMs, through specific :class:`~factory.Factory` subclasses: * Django, with :class:`~factory.django.DjangoModelFactory` * Mogo, with :class:`~factory.mogo.MogoFactory` * MongoEngine, with :class:`~factory.mongoengine.MongoEngineFactory` * SQLAlchemy, with :class:`~factory.alchemy.SQLAlchemyModelFactory` Contributing ------------ factory_boy is distributed under the MIT License. Issues should be opened through `GitHub Issues `_; whenever possible, a pull request should be included. All pull request should pass the test suite, which can be launched simply with: .. code-block:: sh $ python setup.py test .. note:: Running test requires the unittest2 (standard in Python 2.7+) and mock libraries. In order to test coverage, please use: .. code-block:: sh $ pip install coverage $ coverage erase; coverage run --branch setup.py test; coverage report Contents, indices and tables ---------------------------- .. toctree:: :maxdepth: 2 introduction reference orms recipes fuzzy examples internals changelog ideas * :ref:`genindex` * :ref:`modindex` * :ref:`search`