fixtion 0.0.1

fixtion: Test fixture function definition in Python using context manager style generators.

A basic fixture function definition:

>>> from fixtion import fixture
>>>
>>> @fixture
... def basic_fixture():
...   print 'enter basic fixture'
...   yield
...   print 'exit basic fixture'

Decorating a test function with the basic fixture function will wrap the setup and teardown code (the stuff before and after the yield) around the test function invocation:

>>> @basic_fixture
... def test_basic():
...   print '-- A test setup with a basic fixture'
>>>
>>> test_basic()
enter basic fixture
-- A test setup with a basic fixture
exit basic fixture

Decorating unittest.TestCase test methods work, too:

>>> import unittest
>>>
>>> class Tester(unittest.TestCase):
...   @basic_fixture
...   def test_foo(self):
...     print '-- a standard unittest fixtured using fixtion'
>>>
>>> tester = Tester('test_foo')
>>> tester.test_foo()
enter basic fixture
-- a standard unittest fixtured using fixtion
exit basic fixture

Change and restore os.environ:

>>> import os
>>>
>>> @fixture
... def environ_fixture(**kwargs):
...   # Save the original environment values then update the environ.
...   original = {k: v for k, v in os.environ.iteritems() if k in kwargs}
...   os.environ.update(**kwargs)
...
...   yield
...
...   # Restore the original environment values.
...   for key in kwargs:
...     os.environ.pop(key)
...   os.environ.update(**original)
>>>
>>> @environ_fixture(foo='bar')
... def test_environ():
...   print 'foo: %r' % os.environ['foo']
>>>
>>> test_environ()
foo: 'bar'
>>>
>>> 'foo' in os.environ
False

Return some test context:

>>> @fixture
... def login_fixture():
...   class context(object):
...     username = 'ksoze'
...
...   yield context()
>>>
>>> @login_fixture
... def test_login(context):
...   print context.username
>>>
>>> test_login()
ksoze

Works with mock.patch:

>>> import random
>>> import mock
>>>
>>> @fixture
... @mock.patch('random.randint', return_value=123)
... def patched_fixture(randint):
...   yield
>>>
>>> @patched_fixture
... def test_patched():
...     print 'A random number between 1 and 10: %r' % random.randint(1, 10)
...     print 'courtesy of %r' % random.randint
>>>
>>> test_patched()
A random number between 1 and 10: 123
courtesy of <MagicMock name='randint' ...>
>>>
>>> random.randint
<bound method Random.randint of <random.Random object at ...>>

The previous os.environ example can be really simplified:

>>> @fixture
... def environ_fixture(**kwargs):
...   with mock.patch.dict('os.environ', kwargs):
...     yield
>>>
>>> @environ_fixture(foo='bar')
... def test_environ():
...   print 'foo: %r' % os.environ['foo']
>>>
>>> test_environ()
foo: 'bar'
>>>
>>> 'foo' in os.environ
False