diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst index 0c1cecf45381e2..d8ba24c3146cf2 100644 --- a/Doc/library/unittest.mock.rst +++ b/Doc/library/unittest.mock.rst @@ -2584,40 +2584,16 @@ called incorrectly. Before I explain how auto-speccing works, here's why it is needed. -:class:`Mock` is a very powerful and flexible object, but it suffers from two flaws -when used to mock out objects from a system under test. One of these flaws is -specific to the :class:`Mock` api and the other is a more general problem with using -mock objects. - -First the problem specific to :class:`Mock`. :class:`Mock` has two assert methods that are -extremely handy: :meth:`~Mock.assert_called_with` and -:meth:`~Mock.assert_called_once_with`. - - >>> mock = Mock(name='Thing', return_value=None) - >>> mock(1, 2, 3) - >>> mock.assert_called_once_with(1, 2, 3) - >>> mock(1, 2, 3) - >>> mock.assert_called_once_with(1, 2, 3) - Traceback (most recent call last): - ... - AssertionError: Expected 'mock' to be called once. Called 2 times. - -Because mocks auto-create attributes on demand, and allow you to call them -with arbitrary arguments, if you misspell one of these assert methods then -your assertion is gone: - -.. code-block:: pycon - - >>> mock = Mock(name='Thing', return_value=None) - >>> mock(1, 2, 3) - >>> mock.assret_called_once_with(4, 5, 6) # Intentional typo! +:class:`Mock` is a very powerful and flexible object, but it suffers from a flaw which +is general to mocking. If you refactor some of your code, rename members and so on, any +tests for code that is still using the *old api* but uses mocks instead of the real +objects will still pass. This means your tests can all pass even though your code is +broken. -Your tests can pass silently and incorrectly because of the typo. +.. versionchanged:: 3.5 -The second issue is more general to mocking. If you refactor some of your -code, rename members and so on, any tests for code that is still using the -*old api* but uses mocks instead of the real objects will still pass. This -means your tests can all pass even though your code is broken. + Before 3.5, tests with a typo in the word assert would silently pass when they should + raise an error. You can still achieve this behavior by passing ``unsafe=True`` to Mock. Note that this is another reason why you need integration tests as well as unit tests. Testing everything in isolation is all fine and dandy, but if you
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