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					@ -20,10 +20,6 @@ The list of modules described in this chapter is:
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   doctest.rst
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					   doctest.rst
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   unittest.rst
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					   unittest.rst
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   unittest.mock.rst
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					   unittest.mock.rst
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   unittest.mock-patch.rst
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   unittest.mock-magicmethods.rst
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   unittest.mock-helpers.rst
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   unittest.mock-getting-started.rst
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   unittest.mock-examples.rst
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					   unittest.mock-examples.rst
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   2to3.rst
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					   2to3.rst
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   test.rst
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					   test.rst
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					@ -1,18 +1,427 @@
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.. _further-examples:
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					:mod:`unittest.mock` --- getting started
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					========================================
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:mod:`unittest.mock` --- further examples
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=========================================
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.. module:: unittest.mock
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   :synopsis: Mock object library.
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.. moduleauthor:: Michael Foord <michael@python.org>
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					.. moduleauthor:: Michael Foord <michael@python.org>
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.. currentmodule:: unittest.mock
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					.. currentmodule:: unittest.mock
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.. versionadded:: 3.3
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					.. versionadded:: 3.3
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Here are some more examples for some slightly more advanced scenarios than in
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					.. _getting-started:
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the :ref:`getting started <getting-started>` guide.
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					Using Mock
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					----------
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					Mock Patching Methods
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					~~~~~~~~~~~~~~~~~~~~~
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					Common uses for :class:`Mock` objects include:
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					* Patching methods
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					* Recording method calls on objects
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					You might want to replace a method on an object to check that
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					it is called with the correct arguments by another part of the system:
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					    >>> real = SomeClass()
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					    >>> real.method = MagicMock(name='method')
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					    >>> real.method(3, 4, 5, key='value')
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					    <MagicMock name='method()' id='...'>
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					Once our mock has been used (`real.method` in this example) it has methods
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					and attributes that allow you to make assertions about how it has been used.
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					.. note::
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					    In most of these examples the :class:`Mock` and :class:`MagicMock` classes
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					    are interchangeable. As the `MagicMock` is the more capable class it makes
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					    a sensible one to use by default.
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					Once the mock has been called its :attr:`~Mock.called` attribute is set to
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					`True`. More importantly we can use the :meth:`~Mock.assert_called_with` or
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					:meth`~Mock.assert_called_once_with` method to check that it was called with
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					the correct arguments.
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					This example tests that calling `ProductionClass().method` results in a call to
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					the `something` method:
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					    >>> class ProductionClass(object):
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					    ...     def method(self):
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					    ...         self.something(1, 2, 3)
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					    ...     def something(self, a, b, c):
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					    ...         pass
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					    ...
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					    >>> real = ProductionClass()
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					    >>> real.something = MagicMock()
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					    >>> real.method()
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					    >>> real.something.assert_called_once_with(1, 2, 3)
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					Mock for Method Calls on an Object
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					~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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					In the last example we patched a method directly on an object to check that it
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					was called correctly. Another common use case is to pass an object into a
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					method (or some part of the system under test) and then check that it is used
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					in the correct way.
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					The simple `ProductionClass` below has a `closer` method. If it is called with
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					an object then it calls `close` on it.
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					    >>> class ProductionClass(object):
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					    ...     def closer(self, something):
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					    ...         something.close()
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					    ...
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					So to test it we need to pass in an object with a `close` method and check
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					that it was called correctly.
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					    >>> real = ProductionClass()
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					    >>> mock = Mock()
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					    >>> real.closer(mock)
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					    >>> mock.close.assert_called_with()
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					We don't have to do any work to provide the 'close' method on our mock.
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					Accessing close creates it. So, if 'close' hasn't already been called then
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					accessing it in the test will create it, but :meth:`~Mock.assert_called_with`
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					will raise a failure exception.
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					Mocking Classes
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					~~~~~~~~~~~~~~~
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					A common use case is to mock out classes instantiated by your code under test.
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					When you patch a class, then that class is replaced with a mock. Instances
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					are created by *calling the class*. This means you access the "mock instance"
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					by looking at the return value of the mocked class.
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					In the example below we have a function `some_function` that instantiates `Foo`
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					and calls a method on it. The call to `patch` replaces the class `Foo` with a
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					mock. The `Foo` instance is the result of calling the mock, so it is configured
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					by modify the mock :attr:`~Mock.return_value`.
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					    >>> def some_function():
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					    ...     instance = module.Foo()
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					    ...     return instance.method()
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					    ...
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					    >>> with patch('module.Foo') as mock:
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					    ...     instance = mock.return_value
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					    ...     instance.method.return_value = 'the result'
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					    ...     result = some_function()
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					    ...     assert result == 'the result'
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					Naming your mocks
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					~~~~~~~~~~~~~~~~~
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					It can be useful to give your mocks a name. The name is shown in the repr of
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					the mock and can be helpful when the mock appears in test failure messages. The
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					name is also propagated to attributes or methods of the mock:
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					    >>> mock = MagicMock(name='foo')
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					    >>> mock
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					    <MagicMock name='foo' id='...'>
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					    >>> mock.method
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					    <MagicMock name='foo.method' id='...'>
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					Tracking all Calls
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					~~~~~~~~~~~~~~~~~~
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					Often you want to track more than a single call to a method. The
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					:attr:`~Mock.mock_calls` attribute records all calls
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					to child attributes of the mock - and also to their children.
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					    >>> mock = MagicMock()
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					    >>> mock.method()
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					    <MagicMock name='mock.method()' id='...'>
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					    >>> mock.attribute.method(10, x=53)
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					    <MagicMock name='mock.attribute.method()' id='...'>
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					    >>> mock.mock_calls
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					    [call.method(), call.attribute.method(10, x=53)]
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					If you make an assertion about `mock_calls` and any unexpected methods
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					have been called, then the assertion will fail. This is useful because as well
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					as asserting that the calls you expected have been made, you are also checking
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					that they were made in the right order and with no additional calls:
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					You use the :data:`call` object to construct lists for comparing with
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					`mock_calls`:
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					    >>> expected = [call.method(), call.attribute.method(10, x=53)]
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					    >>> mock.mock_calls == expected
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					    True
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					Setting Return Values and Attributes
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					~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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					Setting the return values on a mock object is trivially easy:
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					    >>> mock = Mock()
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					    >>> mock.return_value = 3
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					    >>> mock()
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					    3
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					Of course you can do the same for methods on the mock:
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					    >>> mock = Mock()
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					    >>> mock.method.return_value = 3
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					    >>> mock.method()
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					    3
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					The return value can also be set in the constructor:
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					    >>> mock = Mock(return_value=3)
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					    >>> mock()
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					    3
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					If you need an attribute setting on your mock, just do it:
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					    >>> mock = Mock()
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					    >>> mock.x = 3
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					    >>> mock.x
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					    3
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					Sometimes you want to mock up a more complex situation, like for example
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					`mock.connection.cursor().execute("SELECT 1")`. If we wanted this call to
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					return a list, then we have to configure the result of the nested call.
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					We can use :data:`call` to construct the set of calls in a "chained call" like
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					this for easy assertion afterwards:
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					    >>> mock = Mock()
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					    >>> cursor = mock.connection.cursor.return_value
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					    >>> cursor.execute.return_value = ['foo']
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					    >>> mock.connection.cursor().execute("SELECT 1")
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					    ['foo']
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					    >>> expected = call.connection.cursor().execute("SELECT 1").call_list()
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					    >>> mock.mock_calls
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					    [call.connection.cursor(), call.connection.cursor().execute('SELECT 1')]
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					    >>> mock.mock_calls == expected
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					    True
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					It is the call to `.call_list()` that turns our call object into a list of
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					calls representing the chained calls.
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					Raising exceptions with mocks
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					~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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					A useful attribute is :attr:`~Mock.side_effect`. If you set this to an
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					exception class or instance then the exception will be raised when the mock
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					is called.
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					    >>> mock = Mock(side_effect=Exception('Boom!'))
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					    >>> mock()
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					    Traceback (most recent call last):
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					      ...
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					    Exception: Boom!
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					Side effect functions and iterables
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					~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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					`side_effect` can also be set to a function or an iterable. The use case for
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					`side_effect` as an iterable is where your mock is going to be called several
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					times, and you want each call to return a different value. When you set
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					`side_effect` to an iterable every call to the mock returns the next value
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					from the iterable:
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					    >>> mock = MagicMock(side_effect=[4, 5, 6])
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					    >>> mock()
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					    4
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					    >>> mock()
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					    5
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					    >>> mock()
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					    6
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					For more advanced use cases, like dynamically varying the return values
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					depending on what the mock is called with, `side_effect` can be a function.
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					The function will be called with the same arguments as the mock. Whatever the
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					function returns is what the call returns:
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					    >>> vals = {(1, 2): 1, (2, 3): 2}
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					    >>> def side_effect(*args):
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					    ...     return vals[args]
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					    ...
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					    >>> mock = MagicMock(side_effect=side_effect)
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					    >>> mock(1, 2)
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					    1
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					    >>> mock(2, 3)
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					    2
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					Creating a Mock from an Existing Object
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					~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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					One problem with over use of mocking is that it couples your tests to the
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					implementation of your mocks rather than your real code. Suppose you have a
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					class that implements `some_method`. In a test for another class, you
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					provide a mock of this object that *also* provides `some_method`. If later
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					you refactor the first class, so that it no longer has `some_method` - then
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					your tests will continue to pass even though your code is now broken!
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					`Mock` allows you to provide an object as a specification for the mock,
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					using the `spec` keyword argument. Accessing methods / attributes on the
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					mock that don't exist on your specification object will immediately raise an
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					attribute error. If you change the implementation of your specification, then
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					tests that use that class will start failing immediately without you having to
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					instantiate the class in those tests.
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					    >>> mock = Mock(spec=SomeClass)
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					    >>> mock.old_method()
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					    Traceback (most recent call last):
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					       ...
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					    AttributeError: object has no attribute 'old_method'
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					If you want a stronger form of specification that prevents the setting
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					of arbitrary attributes as well as the getting of them then you can use
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					`spec_set` instead of `spec`.
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 | 
					Patch Decorators
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 | 
					----------------
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 | 
					.. note::
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 | 
				
			||||||
 | 
					   With `patch` it matters that you patch objects in the namespace where they
 | 
				
			||||||
 | 
					   are looked up. This is normally straightforward, but for a quick guide
 | 
				
			||||||
 | 
					   read :ref:`where to patch <where-to-patch>`.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					A common need in tests is to patch a class attribute or a module attribute,
 | 
				
			||||||
 | 
					for example patching a builtin or patching a class in a module to test that it
 | 
				
			||||||
 | 
					is instantiated. Modules and classes are effectively global, so patching on
 | 
				
			||||||
 | 
					them has to be undone after the test or the patch will persist into other
 | 
				
			||||||
 | 
					tests and cause hard to diagnose problems.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					mock provides three convenient decorators for this: `patch`, `patch.object` and
 | 
				
			||||||
 | 
					`patch.dict`. `patch` takes a single string, of the form
 | 
				
			||||||
 | 
					`package.module.Class.attribute` to specify the attribute you are patching. It
 | 
				
			||||||
 | 
					also optionally takes a value that you want the attribute (or class or
 | 
				
			||||||
 | 
					whatever) to be replaced with. 'patch.object' takes an object and the name of
 | 
				
			||||||
 | 
					the attribute you would like patched, plus optionally the value to patch it
 | 
				
			||||||
 | 
					with.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					`patch.object`:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> original = SomeClass.attribute
 | 
				
			||||||
 | 
					    >>> @patch.object(SomeClass, 'attribute', sentinel.attribute)
 | 
				
			||||||
 | 
					    ... def test():
 | 
				
			||||||
 | 
					    ...     assert SomeClass.attribute == sentinel.attribute
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> test()
 | 
				
			||||||
 | 
					    >>> assert SomeClass.attribute == original
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> @patch('package.module.attribute', sentinel.attribute)
 | 
				
			||||||
 | 
					    ... def test():
 | 
				
			||||||
 | 
					    ...     from package.module import attribute
 | 
				
			||||||
 | 
					    ...     assert attribute is sentinel.attribute
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> test()
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					If you are patching a module (including `__builtin__`) then use `patch`
 | 
				
			||||||
 | 
					instead of `patch.object`:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> mock = MagicMock(return_value = sentinel.file_handle)
 | 
				
			||||||
 | 
					    >>> with patch('__builtin__.open', mock):
 | 
				
			||||||
 | 
					    ...     handle = open('filename', 'r')
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> mock.assert_called_with('filename', 'r')
 | 
				
			||||||
 | 
					    >>> assert handle == sentinel.file_handle, "incorrect file handle returned"
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					The module name can be 'dotted', in the form `package.module` if needed:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> @patch('package.module.ClassName.attribute', sentinel.attribute)
 | 
				
			||||||
 | 
					    ... def test():
 | 
				
			||||||
 | 
					    ...     from package.module import ClassName
 | 
				
			||||||
 | 
					    ...     assert ClassName.attribute == sentinel.attribute
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> test()
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					A nice pattern is to actually decorate test methods themselves:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> class MyTest(unittest2.TestCase):
 | 
				
			||||||
 | 
					    ...     @patch.object(SomeClass, 'attribute', sentinel.attribute)
 | 
				
			||||||
 | 
					    ...     def test_something(self):
 | 
				
			||||||
 | 
					    ...         self.assertEqual(SomeClass.attribute, sentinel.attribute)
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> original = SomeClass.attribute
 | 
				
			||||||
 | 
					    >>> MyTest('test_something').test_something()
 | 
				
			||||||
 | 
					    >>> assert SomeClass.attribute == original
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					If you want to patch with a Mock, you can use `patch` with only one argument
 | 
				
			||||||
 | 
					(or `patch.object` with two arguments). The mock will be created for you and
 | 
				
			||||||
 | 
					passed into the test function / method:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> class MyTest(unittest2.TestCase):
 | 
				
			||||||
 | 
					    ...     @patch.object(SomeClass, 'static_method')
 | 
				
			||||||
 | 
					    ...     def test_something(self, mock_method):
 | 
				
			||||||
 | 
					    ...         SomeClass.static_method()
 | 
				
			||||||
 | 
					    ...         mock_method.assert_called_with()
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> MyTest('test_something').test_something()
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					You can stack up multiple patch decorators using this pattern:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> class MyTest(unittest2.TestCase):
 | 
				
			||||||
 | 
					    ...     @patch('package.module.ClassName1')
 | 
				
			||||||
 | 
					    ...     @patch('package.module.ClassName2')
 | 
				
			||||||
 | 
					    ...     def test_something(self, MockClass2, MockClass1):
 | 
				
			||||||
 | 
					    ...         self.assertTrue(package.module.ClassName1 is MockClass1)
 | 
				
			||||||
 | 
					    ...         self.assertTrue(package.module.ClassName2 is MockClass2)
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> MyTest('test_something').test_something()
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					When you nest patch decorators the mocks are passed in to the decorated
 | 
				
			||||||
 | 
					function in the same order they applied (the normal *python* order that
 | 
				
			||||||
 | 
					decorators are applied). This means from the bottom up, so in the example
 | 
				
			||||||
 | 
					above the mock for `test_module.ClassName2` is passed in first.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					There is also :func:`patch.dict` for setting values in a dictionary just
 | 
				
			||||||
 | 
					during a scope and restoring the dictionary to its original state when the test
 | 
				
			||||||
 | 
					ends:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					   >>> foo = {'key': 'value'}
 | 
				
			||||||
 | 
					   >>> original = foo.copy()
 | 
				
			||||||
 | 
					   >>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
 | 
				
			||||||
 | 
					   ...     assert foo == {'newkey': 'newvalue'}
 | 
				
			||||||
 | 
					   ...
 | 
				
			||||||
 | 
					   >>> assert foo == original
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					`patch`, `patch.object` and `patch.dict` can all be used as context managers.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Where you use `patch` to create a mock for you, you can get a reference to the
 | 
				
			||||||
 | 
					mock using the "as" form of the with statement:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					    >>> class ProductionClass(object):
 | 
				
			||||||
 | 
					    ...     def method(self):
 | 
				
			||||||
 | 
					    ...         pass
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> with patch.object(ProductionClass, 'method') as mock_method:
 | 
				
			||||||
 | 
					    ...     mock_method.return_value = None
 | 
				
			||||||
 | 
					    ...     real = ProductionClass()
 | 
				
			||||||
 | 
					    ...     real.method(1, 2, 3)
 | 
				
			||||||
 | 
					    ...
 | 
				
			||||||
 | 
					    >>> mock_method.assert_called_with(1, 2, 3)
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					As an alternative `patch`, `patch.object` and `patch.dict` can be used as
 | 
				
			||||||
 | 
					class decorators. When used in this way it is the same as applying the
 | 
				
			||||||
 | 
					decorator indvidually to every method whose name starts with "test".
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					.. _further-examples:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Further Examples
 | 
				
			||||||
 | 
					================
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Here are some more examples for some slightly more advanced scenarios.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Mocking chained calls
 | 
					Mocking chained calls
 | 
				
			||||||
| 
						 | 
					
 | 
				
			||||||
| 
						 | 
					@ -1,419 +0,0 @@
 | 
				
			||||||
:mod:`unittest.mock` --- getting started
 | 
					 | 
				
			||||||
========================================
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. module:: unittest.mock
 | 
					 | 
				
			||||||
   :synopsis: Mock object library.
 | 
					 | 
				
			||||||
.. moduleauthor:: Michael Foord <michael@python.org>
 | 
					 | 
				
			||||||
.. currentmodule:: unittest.mock
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. versionadded:: 3.3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. _getting-started:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Using Mock
 | 
					 | 
				
			||||||
----------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Mock Patching Methods
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Common uses for :class:`Mock` objects include:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* Patching methods
 | 
					 | 
				
			||||||
* Recording method calls on objects
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You might want to replace a method on an object to check that
 | 
					 | 
				
			||||||
it is called with the correct arguments by another part of the system:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> real = SomeClass()
 | 
					 | 
				
			||||||
    >>> real.method = MagicMock(name='method')
 | 
					 | 
				
			||||||
    >>> real.method(3, 4, 5, key='value')
 | 
					 | 
				
			||||||
    <MagicMock name='method()' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Once our mock has been used (`real.method` in this example) it has methods
 | 
					 | 
				
			||||||
and attributes that allow you to make assertions about how it has been used.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. note::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    In most of these examples the :class:`Mock` and :class:`MagicMock` classes
 | 
					 | 
				
			||||||
    are interchangeable. As the `MagicMock` is the more capable class it makes
 | 
					 | 
				
			||||||
    a sensible one to use by default.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Once the mock has been called its :attr:`~Mock.called` attribute is set to
 | 
					 | 
				
			||||||
`True`. More importantly we can use the :meth:`~Mock.assert_called_with` or
 | 
					 | 
				
			||||||
:meth`~Mock.assert_called_once_with` method to check that it was called with
 | 
					 | 
				
			||||||
the correct arguments.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
This example tests that calling `ProductionClass().method` results in a call to
 | 
					 | 
				
			||||||
the `something` method:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class ProductionClass(object):
 | 
					 | 
				
			||||||
    ...     def method(self):
 | 
					 | 
				
			||||||
    ...         self.something(1, 2, 3)
 | 
					 | 
				
			||||||
    ...     def something(self, a, b, c):
 | 
					 | 
				
			||||||
    ...         pass
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> real = ProductionClass()
 | 
					 | 
				
			||||||
    >>> real.something = MagicMock()
 | 
					 | 
				
			||||||
    >>> real.method()
 | 
					 | 
				
			||||||
    >>> real.something.assert_called_once_with(1, 2, 3)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Mock for Method Calls on an Object
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
In the last example we patched a method directly on an object to check that it
 | 
					 | 
				
			||||||
was called correctly. Another common use case is to pass an object into a
 | 
					 | 
				
			||||||
method (or some part of the system under test) and then check that it is used
 | 
					 | 
				
			||||||
in the correct way.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The simple `ProductionClass` below has a `closer` method. If it is called with
 | 
					 | 
				
			||||||
an object then it calls `close` on it.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class ProductionClass(object):
 | 
					 | 
				
			||||||
    ...     def closer(self, something):
 | 
					 | 
				
			||||||
    ...         something.close()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
So to test it we need to pass in an object with a `close` method and check
 | 
					 | 
				
			||||||
that it was called correctly.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> real = ProductionClass()
 | 
					 | 
				
			||||||
    >>> mock = Mock()
 | 
					 | 
				
			||||||
    >>> real.closer(mock)
 | 
					 | 
				
			||||||
    >>> mock.close.assert_called_with()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
We don't have to do any work to provide the 'close' method on our mock.
 | 
					 | 
				
			||||||
Accessing close creates it. So, if 'close' hasn't already been called then
 | 
					 | 
				
			||||||
accessing it in the test will create it, but :meth:`~Mock.assert_called_with`
 | 
					 | 
				
			||||||
will raise a failure exception.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Mocking Classes
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A common use case is to mock out classes instantiated by your code under test.
 | 
					 | 
				
			||||||
When you patch a class, then that class is replaced with a mock. Instances
 | 
					 | 
				
			||||||
are created by *calling the class*. This means you access the "mock instance"
 | 
					 | 
				
			||||||
by looking at the return value of the mocked class.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
In the example below we have a function `some_function` that instantiates `Foo`
 | 
					 | 
				
			||||||
and calls a method on it. The call to `patch` replaces the class `Foo` with a
 | 
					 | 
				
			||||||
mock. The `Foo` instance is the result of calling the mock, so it is configured
 | 
					 | 
				
			||||||
by modify the mock :attr:`~Mock.return_value`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> def some_function():
 | 
					 | 
				
			||||||
    ...     instance = module.Foo()
 | 
					 | 
				
			||||||
    ...     return instance.method()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> with patch('module.Foo') as mock:
 | 
					 | 
				
			||||||
    ...     instance = mock.return_value
 | 
					 | 
				
			||||||
    ...     instance.method.return_value = 'the result'
 | 
					 | 
				
			||||||
    ...     result = some_function()
 | 
					 | 
				
			||||||
    ...     assert result == 'the result'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Naming your mocks
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
It can be useful to give your mocks a name. The name is shown in the repr of
 | 
					 | 
				
			||||||
the mock and can be helpful when the mock appears in test failure messages. The
 | 
					 | 
				
			||||||
name is also propagated to attributes or methods of the mock:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = MagicMock(name='foo')
 | 
					 | 
				
			||||||
    >>> mock
 | 
					 | 
				
			||||||
    <MagicMock name='foo' id='...'>
 | 
					 | 
				
			||||||
    >>> mock.method
 | 
					 | 
				
			||||||
    <MagicMock name='foo.method' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Tracking all Calls
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Often you want to track more than a single call to a method. The
 | 
					 | 
				
			||||||
:attr:`~Mock.mock_calls` attribute records all calls
 | 
					 | 
				
			||||||
to child attributes of the mock - and also to their children.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = MagicMock()
 | 
					 | 
				
			||||||
    >>> mock.method()
 | 
					 | 
				
			||||||
    <MagicMock name='mock.method()' id='...'>
 | 
					 | 
				
			||||||
    >>> mock.attribute.method(10, x=53)
 | 
					 | 
				
			||||||
    <MagicMock name='mock.attribute.method()' id='...'>
 | 
					 | 
				
			||||||
    >>> mock.mock_calls
 | 
					 | 
				
			||||||
    [call.method(), call.attribute.method(10, x=53)]
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you make an assertion about `mock_calls` and any unexpected methods
 | 
					 | 
				
			||||||
have been called, then the assertion will fail. This is useful because as well
 | 
					 | 
				
			||||||
as asserting that the calls you expected have been made, you are also checking
 | 
					 | 
				
			||||||
that they were made in the right order and with no additional calls:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You use the :data:`call` object to construct lists for comparing with
 | 
					 | 
				
			||||||
`mock_calls`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> expected = [call.method(), call.attribute.method(10, x=53)]
 | 
					 | 
				
			||||||
    >>> mock.mock_calls == expected
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Setting Return Values and Attributes
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Setting the return values on a mock object is trivially easy:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock()
 | 
					 | 
				
			||||||
    >>> mock.return_value = 3
 | 
					 | 
				
			||||||
    >>> mock()
 | 
					 | 
				
			||||||
    3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Of course you can do the same for methods on the mock:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock()
 | 
					 | 
				
			||||||
    >>> mock.method.return_value = 3
 | 
					 | 
				
			||||||
    >>> mock.method()
 | 
					 | 
				
			||||||
    3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The return value can also be set in the constructor:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock(return_value=3)
 | 
					 | 
				
			||||||
    >>> mock()
 | 
					 | 
				
			||||||
    3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you need an attribute setting on your mock, just do it:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock()
 | 
					 | 
				
			||||||
    >>> mock.x = 3
 | 
					 | 
				
			||||||
    >>> mock.x
 | 
					 | 
				
			||||||
    3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Sometimes you want to mock up a more complex situation, like for example
 | 
					 | 
				
			||||||
`mock.connection.cursor().execute("SELECT 1")`. If we wanted this call to
 | 
					 | 
				
			||||||
return a list, then we have to configure the result of the nested call.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
We can use :data:`call` to construct the set of calls in a "chained call" like
 | 
					 | 
				
			||||||
this for easy assertion afterwards:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock()
 | 
					 | 
				
			||||||
    >>> cursor = mock.connection.cursor.return_value
 | 
					 | 
				
			||||||
    >>> cursor.execute.return_value = ['foo']
 | 
					 | 
				
			||||||
    >>> mock.connection.cursor().execute("SELECT 1")
 | 
					 | 
				
			||||||
    ['foo']
 | 
					 | 
				
			||||||
    >>> expected = call.connection.cursor().execute("SELECT 1").call_list()
 | 
					 | 
				
			||||||
    >>> mock.mock_calls
 | 
					 | 
				
			||||||
    [call.connection.cursor(), call.connection.cursor().execute('SELECT 1')]
 | 
					 | 
				
			||||||
    >>> mock.mock_calls == expected
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
It is the call to `.call_list()` that turns our call object into a list of
 | 
					 | 
				
			||||||
calls representing the chained calls.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Raising exceptions with mocks
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A useful attribute is :attr:`~Mock.side_effect`. If you set this to an
 | 
					 | 
				
			||||||
exception class or instance then the exception will be raised when the mock
 | 
					 | 
				
			||||||
is called.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock(side_effect=Exception('Boom!'))
 | 
					 | 
				
			||||||
    >>> mock()
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
      ...
 | 
					 | 
				
			||||||
    Exception: Boom!
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Side effect functions and iterables
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`side_effect` can also be set to a function or an iterable. The use case for
 | 
					 | 
				
			||||||
`side_effect` as an iterable is where your mock is going to be called several
 | 
					 | 
				
			||||||
times, and you want each call to return a different value. When you set
 | 
					 | 
				
			||||||
`side_effect` to an iterable every call to the mock returns the next value
 | 
					 | 
				
			||||||
from the iterable:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = MagicMock(side_effect=[4, 5, 6])
 | 
					 | 
				
			||||||
    >>> mock()
 | 
					 | 
				
			||||||
    4
 | 
					 | 
				
			||||||
    >>> mock()
 | 
					 | 
				
			||||||
    5
 | 
					 | 
				
			||||||
    >>> mock()
 | 
					 | 
				
			||||||
    6
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
For more advanced use cases, like dynamically varying the return values
 | 
					 | 
				
			||||||
depending on what the mock is called with, `side_effect` can be a function.
 | 
					 | 
				
			||||||
The function will be called with the same arguments as the mock. Whatever the
 | 
					 | 
				
			||||||
function returns is what the call returns:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> vals = {(1, 2): 1, (2, 3): 2}
 | 
					 | 
				
			||||||
    >>> def side_effect(*args):
 | 
					 | 
				
			||||||
    ...     return vals[args]
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> mock = MagicMock(side_effect=side_effect)
 | 
					 | 
				
			||||||
    >>> mock(1, 2)
 | 
					 | 
				
			||||||
    1
 | 
					 | 
				
			||||||
    >>> mock(2, 3)
 | 
					 | 
				
			||||||
    2
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Creating a Mock from an Existing Object
 | 
					 | 
				
			||||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
One problem with over use of mocking is that it couples your tests to the
 | 
					 | 
				
			||||||
implementation of your mocks rather than your real code. Suppose you have a
 | 
					 | 
				
			||||||
class that implements `some_method`. In a test for another class, you
 | 
					 | 
				
			||||||
provide a mock of this object that *also* provides `some_method`. If later
 | 
					 | 
				
			||||||
you refactor the first class, so that it no longer has `some_method` - then
 | 
					 | 
				
			||||||
your tests will continue to pass even though your code is now broken!
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`Mock` allows you to provide an object as a specification for the mock,
 | 
					 | 
				
			||||||
using the `spec` keyword argument. Accessing methods / attributes on the
 | 
					 | 
				
			||||||
mock that don't exist on your specification object will immediately raise an
 | 
					 | 
				
			||||||
attribute error. If you change the implementation of your specification, then
 | 
					 | 
				
			||||||
tests that use that class will start failing immediately without you having to
 | 
					 | 
				
			||||||
instantiate the class in those tests.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock(spec=SomeClass)
 | 
					 | 
				
			||||||
    >>> mock.old_method()
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
       ...
 | 
					 | 
				
			||||||
    AttributeError: object has no attribute 'old_method'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you want a stronger form of specification that prevents the setting
 | 
					 | 
				
			||||||
of arbitrary attributes as well as the getting of them then you can use
 | 
					 | 
				
			||||||
`spec_set` instead of `spec`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Patch Decorators
 | 
					 | 
				
			||||||
----------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. note::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   With `patch` it matters that you patch objects in the namespace where they
 | 
					 | 
				
			||||||
   are looked up. This is normally straightforward, but for a quick guide
 | 
					 | 
				
			||||||
   read :ref:`where to patch <where-to-patch>`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A common need in tests is to patch a class attribute or a module attribute,
 | 
					 | 
				
			||||||
for example patching a builtin or patching a class in a module to test that it
 | 
					 | 
				
			||||||
is instantiated. Modules and classes are effectively global, so patching on
 | 
					 | 
				
			||||||
them has to be undone after the test or the patch will persist into other
 | 
					 | 
				
			||||||
tests and cause hard to diagnose problems.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
mock provides three convenient decorators for this: `patch`, `patch.object` and
 | 
					 | 
				
			||||||
`patch.dict`. `patch` takes a single string, of the form
 | 
					 | 
				
			||||||
`package.module.Class.attribute` to specify the attribute you are patching. It
 | 
					 | 
				
			||||||
also optionally takes a value that you want the attribute (or class or
 | 
					 | 
				
			||||||
whatever) to be replaced with. 'patch.object' takes an object and the name of
 | 
					 | 
				
			||||||
the attribute you would like patched, plus optionally the value to patch it
 | 
					 | 
				
			||||||
with.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`patch.object`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> original = SomeClass.attribute
 | 
					 | 
				
			||||||
    >>> @patch.object(SomeClass, 'attribute', sentinel.attribute)
 | 
					 | 
				
			||||||
    ... def test():
 | 
					 | 
				
			||||||
    ...     assert SomeClass.attribute == sentinel.attribute
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test()
 | 
					 | 
				
			||||||
    >>> assert SomeClass.attribute == original
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> @patch('package.module.attribute', sentinel.attribute)
 | 
					 | 
				
			||||||
    ... def test():
 | 
					 | 
				
			||||||
    ...     from package.module import attribute
 | 
					 | 
				
			||||||
    ...     assert attribute is sentinel.attribute
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you are patching a module (including `__builtin__`) then use `patch`
 | 
					 | 
				
			||||||
instead of `patch.object`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = MagicMock(return_value = sentinel.file_handle)
 | 
					 | 
				
			||||||
    >>> with patch('__builtin__.open', mock):
 | 
					 | 
				
			||||||
    ...     handle = open('filename', 'r')
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> mock.assert_called_with('filename', 'r')
 | 
					 | 
				
			||||||
    >>> assert handle == sentinel.file_handle, "incorrect file handle returned"
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The module name can be 'dotted', in the form `package.module` if needed:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> @patch('package.module.ClassName.attribute', sentinel.attribute)
 | 
					 | 
				
			||||||
    ... def test():
 | 
					 | 
				
			||||||
    ...     from package.module import ClassName
 | 
					 | 
				
			||||||
    ...     assert ClassName.attribute == sentinel.attribute
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A nice pattern is to actually decorate test methods themselves:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class MyTest(unittest2.TestCase):
 | 
					 | 
				
			||||||
    ...     @patch.object(SomeClass, 'attribute', sentinel.attribute)
 | 
					 | 
				
			||||||
    ...     def test_something(self):
 | 
					 | 
				
			||||||
    ...         self.assertEqual(SomeClass.attribute, sentinel.attribute)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> original = SomeClass.attribute
 | 
					 | 
				
			||||||
    >>> MyTest('test_something').test_something()
 | 
					 | 
				
			||||||
    >>> assert SomeClass.attribute == original
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you want to patch with a Mock, you can use `patch` with only one argument
 | 
					 | 
				
			||||||
(or `patch.object` with two arguments). The mock will be created for you and
 | 
					 | 
				
			||||||
passed into the test function / method:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class MyTest(unittest2.TestCase):
 | 
					 | 
				
			||||||
    ...     @patch.object(SomeClass, 'static_method')
 | 
					 | 
				
			||||||
    ...     def test_something(self, mock_method):
 | 
					 | 
				
			||||||
    ...         SomeClass.static_method()
 | 
					 | 
				
			||||||
    ...         mock_method.assert_called_with()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> MyTest('test_something').test_something()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You can stack up multiple patch decorators using this pattern:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class MyTest(unittest2.TestCase):
 | 
					 | 
				
			||||||
    ...     @patch('package.module.ClassName1')
 | 
					 | 
				
			||||||
    ...     @patch('package.module.ClassName2')
 | 
					 | 
				
			||||||
    ...     def test_something(self, MockClass2, MockClass1):
 | 
					 | 
				
			||||||
    ...         self.assertTrue(package.module.ClassName1 is MockClass1)
 | 
					 | 
				
			||||||
    ...         self.assertTrue(package.module.ClassName2 is MockClass2)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> MyTest('test_something').test_something()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
When you nest patch decorators the mocks are passed in to the decorated
 | 
					 | 
				
			||||||
function in the same order they applied (the normal *python* order that
 | 
					 | 
				
			||||||
decorators are applied). This means from the bottom up, so in the example
 | 
					 | 
				
			||||||
above the mock for `test_module.ClassName2` is passed in first.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
There is also :func:`patch.dict` for setting values in a dictionary just
 | 
					 | 
				
			||||||
during a scope and restoring the dictionary to its original state when the test
 | 
					 | 
				
			||||||
ends:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> foo = {'key': 'value'}
 | 
					 | 
				
			||||||
   >>> original = foo.copy()
 | 
					 | 
				
			||||||
   >>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
 | 
					 | 
				
			||||||
   ...     assert foo == {'newkey': 'newvalue'}
 | 
					 | 
				
			||||||
   ...
 | 
					 | 
				
			||||||
   >>> assert foo == original
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`patch`, `patch.object` and `patch.dict` can all be used as context managers.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Where you use `patch` to create a mock for you, you can get a reference to the
 | 
					 | 
				
			||||||
mock using the "as" form of the with statement:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class ProductionClass(object):
 | 
					 | 
				
			||||||
    ...     def method(self):
 | 
					 | 
				
			||||||
    ...         pass
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> with patch.object(ProductionClass, 'method') as mock_method:
 | 
					 | 
				
			||||||
    ...     mock_method.return_value = None
 | 
					 | 
				
			||||||
    ...     real = ProductionClass()
 | 
					 | 
				
			||||||
    ...     real.method(1, 2, 3)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> mock_method.assert_called_with(1, 2, 3)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
As an alternative `patch`, `patch.object` and `patch.dict` can be used as
 | 
					 | 
				
			||||||
class decorators. When used in this way it is the same as applying the
 | 
					 | 
				
			||||||
decorator indvidually to every method whose name starts with "test".
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
For some more advanced examples, see the :ref:`further-examples` page.
 | 
					 | 
				
			||||||
| 
						 | 
					@ -1,537 +0,0 @@
 | 
				
			||||||
:mod:`unittest.mock` --- helpers
 | 
					 | 
				
			||||||
================================
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. module:: unittest.mock
 | 
					 | 
				
			||||||
   :synopsis: Mock object library.
 | 
					 | 
				
			||||||
.. moduleauthor:: Michael Foord <michael@python.org>
 | 
					 | 
				
			||||||
.. currentmodule:: unittest.mock
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. versionadded:: 3.3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
sentinel
 | 
					 | 
				
			||||||
--------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. data:: sentinel
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The ``sentinel`` object provides a convenient way of providing unique
 | 
					 | 
				
			||||||
    objects for your tests.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Attributes are created on demand when you access them by name. Accessing
 | 
					 | 
				
			||||||
    the same attribute will always return the same object. The objects
 | 
					 | 
				
			||||||
    returned have a sensible repr so that test failure messages are readable.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Sometimes when testing you need to test that a specific object is passed as an
 | 
					 | 
				
			||||||
argument to another method, or returned. It can be common to create named
 | 
					 | 
				
			||||||
sentinel objects to test this. `sentinel` provides a convenient way of
 | 
					 | 
				
			||||||
creating and testing the identity of objects like this.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
In this example we monkey patch `method` to return `sentinel.some_object`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> real = ProductionClass()
 | 
					 | 
				
			||||||
    >>> real.method = Mock(name="method")
 | 
					 | 
				
			||||||
    >>> real.method.return_value = sentinel.some_object
 | 
					 | 
				
			||||||
    >>> result = real.method()
 | 
					 | 
				
			||||||
    >>> assert result is sentinel.some_object
 | 
					 | 
				
			||||||
    >>> sentinel.some_object
 | 
					 | 
				
			||||||
    sentinel.some_object
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
DEFAULT
 | 
					 | 
				
			||||||
-------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. data:: DEFAULT
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The `DEFAULT` object is a pre-created sentinel (actually
 | 
					 | 
				
			||||||
    `sentinel.DEFAULT`). It can be used by :attr:`~Mock.side_effect`
 | 
					 | 
				
			||||||
    functions to indicate that the normal return value should be used.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
call
 | 
					 | 
				
			||||||
----
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: call(*args, **kwargs)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `call` is a helper object for making simpler assertions, for comparing
 | 
					 | 
				
			||||||
    with :attr:`~Mock.call_args`, :attr:`~Mock.call_args_list`,
 | 
					 | 
				
			||||||
    :attr:`~Mock.mock_calls` and:attr: `~Mock.method_calls`. `call` can also be
 | 
					 | 
				
			||||||
    used with :meth:`~Mock.assert_has_calls`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
        >>> m = MagicMock(return_value=None)
 | 
					 | 
				
			||||||
        >>> m(1, 2, a='foo', b='bar')
 | 
					 | 
				
			||||||
        >>> m()
 | 
					 | 
				
			||||||
        >>> m.call_args_list == [call(1, 2, a='foo', b='bar'), call()]
 | 
					 | 
				
			||||||
        True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. method:: call.call_list()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    For a call object that represents multiple calls, `call_list`
 | 
					 | 
				
			||||||
    returns a list of all the intermediate calls as well as the
 | 
					 | 
				
			||||||
    final call.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`call_list` is particularly useful for making assertions on "chained calls". A
 | 
					 | 
				
			||||||
chained call is multiple calls on a single line of code. This results in
 | 
					 | 
				
			||||||
multiple entries in :attr:`~Mock.mock_calls` on a mock. Manually constructing
 | 
					 | 
				
			||||||
the sequence of calls can be tedious.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
:meth:`~call.call_list` can construct the sequence of calls from the same
 | 
					 | 
				
			||||||
chained call:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> m = MagicMock()
 | 
					 | 
				
			||||||
    >>> m(1).method(arg='foo').other('bar')(2.0)
 | 
					 | 
				
			||||||
    <MagicMock name='mock().method().other()()' id='...'>
 | 
					 | 
				
			||||||
    >>> kall = call(1).method(arg='foo').other('bar')(2.0)
 | 
					 | 
				
			||||||
    >>> kall.call_list()
 | 
					 | 
				
			||||||
    [call(1),
 | 
					 | 
				
			||||||
     call().method(arg='foo'),
 | 
					 | 
				
			||||||
     call().method().other('bar'),
 | 
					 | 
				
			||||||
     call().method().other()(2.0)]
 | 
					 | 
				
			||||||
    >>> m.mock_calls == kall.call_list()
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. _calls-as-tuples:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A `call` object is either a tuple of (positional args, keyword args) or
 | 
					 | 
				
			||||||
(name, positional args, keyword args) depending on how it was constructed. When
 | 
					 | 
				
			||||||
you construct them yourself this isn't particularly interesting, but the `call`
 | 
					 | 
				
			||||||
objects that are in the :attr:`Mock.call_args`, :attr:`Mock.call_args_list` and
 | 
					 | 
				
			||||||
:attr:`Mock.mock_calls` attributes can be introspected to get at the individual
 | 
					 | 
				
			||||||
arguments they contain.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The `call` objects in :attr:`Mock.call_args` and :attr:`Mock.call_args_list`
 | 
					 | 
				
			||||||
are two-tuples of (positional args, keyword args) whereas the `call` objects
 | 
					 | 
				
			||||||
in :attr:`Mock.mock_calls`, along with ones you construct yourself, are
 | 
					 | 
				
			||||||
three-tuples of (name, positional args, keyword args).
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You can use their "tupleness" to pull out the individual arguments for more
 | 
					 | 
				
			||||||
complex introspection and assertions. The positional arguments are a tuple
 | 
					 | 
				
			||||||
(an empty tuple if there are no positional arguments) and the keyword
 | 
					 | 
				
			||||||
arguments are a dictionary:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> m = MagicMock(return_value=None)
 | 
					 | 
				
			||||||
    >>> m(1, 2, 3, arg='one', arg2='two')
 | 
					 | 
				
			||||||
    >>> kall = m.call_args
 | 
					 | 
				
			||||||
    >>> args, kwargs = kall
 | 
					 | 
				
			||||||
    >>> args
 | 
					 | 
				
			||||||
    (1, 2, 3)
 | 
					 | 
				
			||||||
    >>> kwargs
 | 
					 | 
				
			||||||
    {'arg2': 'two', 'arg': 'one'}
 | 
					 | 
				
			||||||
    >>> args is kall[0]
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
    >>> kwargs is kall[1]
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> m = MagicMock()
 | 
					 | 
				
			||||||
    >>> m.foo(4, 5, 6, arg='two', arg2='three')
 | 
					 | 
				
			||||||
    <MagicMock name='mock.foo()' id='...'>
 | 
					 | 
				
			||||||
    >>> kall = m.mock_calls[0]
 | 
					 | 
				
			||||||
    >>> name, args, kwargs = kall
 | 
					 | 
				
			||||||
    >>> name
 | 
					 | 
				
			||||||
    'foo'
 | 
					 | 
				
			||||||
    >>> args
 | 
					 | 
				
			||||||
    (4, 5, 6)
 | 
					 | 
				
			||||||
    >>> kwargs
 | 
					 | 
				
			||||||
    {'arg2': 'three', 'arg': 'two'}
 | 
					 | 
				
			||||||
    >>> name is m.mock_calls[0][0]
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
create_autospec
 | 
					 | 
				
			||||||
---------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: create_autospec(spec, spec_set=False, instance=False, **kwargs)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Create a mock object using another object as a spec. Attributes on the
 | 
					 | 
				
			||||||
    mock will use the corresponding attribute on the `spec` object as their
 | 
					 | 
				
			||||||
    spec.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Functions or methods being mocked will have their arguments checked to
 | 
					 | 
				
			||||||
    ensure that they are called with the correct signature.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    If `spec_set` is `True` then attempting to set attributes that don't exist
 | 
					 | 
				
			||||||
    on the spec object will raise an `AttributeError`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    If a class is used as a spec then the return value of the mock (the
 | 
					 | 
				
			||||||
    instance of the class) will have the same spec. You can use a class as the
 | 
					 | 
				
			||||||
    spec for an instance object by passing `instance=True`. The returned mock
 | 
					 | 
				
			||||||
    will only be callable if instances of the mock are callable.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `create_autospec` also takes arbitrary keyword arguments that are passed to
 | 
					 | 
				
			||||||
    the constructor of the created mock.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
See :ref:`auto-speccing` for examples of how to use auto-speccing with
 | 
					 | 
				
			||||||
`create_autospec` and the `autospec` argument to :func:`patch`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
ANY
 | 
					 | 
				
			||||||
---
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. data:: ANY
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Sometimes you may need to make assertions about *some* of the arguments in a
 | 
					 | 
				
			||||||
call to mock, but either not care about some of the arguments or want to pull
 | 
					 | 
				
			||||||
them individually out of :attr:`~Mock.call_args` and make more complex
 | 
					 | 
				
			||||||
assertions on them.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
To ignore certain arguments you can pass in objects that compare equal to
 | 
					 | 
				
			||||||
*everything*. Calls to :meth:`~Mock.assert_called_with` and
 | 
					 | 
				
			||||||
:meth:`~Mock.assert_called_once_with` will then succeed no matter what was
 | 
					 | 
				
			||||||
passed in.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock = Mock(return_value=None)
 | 
					 | 
				
			||||||
    >>> mock('foo', bar=object())
 | 
					 | 
				
			||||||
    >>> mock.assert_called_once_with('foo', bar=ANY)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`ANY` can also be used in comparisons with call lists like
 | 
					 | 
				
			||||||
:attr:`~Mock.mock_calls`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> m = MagicMock(return_value=None)
 | 
					 | 
				
			||||||
    >>> m(1)
 | 
					 | 
				
			||||||
    >>> m(1, 2)
 | 
					 | 
				
			||||||
    >>> m(object())
 | 
					 | 
				
			||||||
    >>> m.mock_calls == [call(1), call(1, 2), ANY]
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
FILTER_DIR
 | 
					 | 
				
			||||||
----------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. data:: FILTER_DIR
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`FILTER_DIR` is a module level variable that controls the way mock objects
 | 
					 | 
				
			||||||
respond to `dir` (only for Python 2.6 or more recent). The default is `True`,
 | 
					 | 
				
			||||||
which uses the filtering described below, to only show useful members. If you
 | 
					 | 
				
			||||||
dislike this filtering, or need to switch it off for diagnostic purposes, then
 | 
					 | 
				
			||||||
set `mock.FILTER_DIR = False`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
With filtering on, `dir(some_mock)` shows only useful attributes and will
 | 
					 | 
				
			||||||
include any dynamically created attributes that wouldn't normally be shown.
 | 
					 | 
				
			||||||
If the mock was created with a `spec` (or `autospec` of course) then all the
 | 
					 | 
				
			||||||
attributes from the original are shown, even if they haven't been accessed
 | 
					 | 
				
			||||||
yet:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> dir(Mock())
 | 
					 | 
				
			||||||
    ['assert_any_call',
 | 
					 | 
				
			||||||
     'assert_called_once_with',
 | 
					 | 
				
			||||||
     'assert_called_with',
 | 
					 | 
				
			||||||
     'assert_has_calls',
 | 
					 | 
				
			||||||
     'attach_mock',
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
    >>> from urllib import request
 | 
					 | 
				
			||||||
    >>> dir(Mock(spec=request))
 | 
					 | 
				
			||||||
    ['AbstractBasicAuthHandler',
 | 
					 | 
				
			||||||
     'AbstractDigestAuthHandler',
 | 
					 | 
				
			||||||
     'AbstractHTTPHandler',
 | 
					 | 
				
			||||||
     'BaseHandler',
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Many of the not-very-useful (private to `Mock` rather than the thing being
 | 
					 | 
				
			||||||
mocked) underscore and double underscore prefixed attributes have been
 | 
					 | 
				
			||||||
filtered from the result of calling `dir` on a `Mock`. If you dislike this
 | 
					 | 
				
			||||||
behaviour you can switch it off by setting the module level switch
 | 
					 | 
				
			||||||
`FILTER_DIR`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> from unittest import mock
 | 
					 | 
				
			||||||
    >>> mock.FILTER_DIR = False
 | 
					 | 
				
			||||||
    >>> dir(mock.Mock())
 | 
					 | 
				
			||||||
    ['_NonCallableMock__get_return_value',
 | 
					 | 
				
			||||||
     '_NonCallableMock__get_side_effect',
 | 
					 | 
				
			||||||
     '_NonCallableMock__return_value_doc',
 | 
					 | 
				
			||||||
     '_NonCallableMock__set_return_value',
 | 
					 | 
				
			||||||
     '_NonCallableMock__set_side_effect',
 | 
					 | 
				
			||||||
     '__call__',
 | 
					 | 
				
			||||||
     '__class__',
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Alternatively you can just use `vars(my_mock)` (instance members) and
 | 
					 | 
				
			||||||
`dir(type(my_mock))` (type members) to bypass the filtering irrespective of
 | 
					 | 
				
			||||||
`mock.FILTER_DIR`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
mock_open
 | 
					 | 
				
			||||||
---------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: mock_open(mock=None, read_data=None)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    A helper function to create a mock to replace the use of `open`. It works
 | 
					 | 
				
			||||||
    for `open` called directly or used as a context manager.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The `mock` argument is the mock object to configure. If `None` (the
 | 
					 | 
				
			||||||
    default) then a `MagicMock` will be created for you, with the API limited
 | 
					 | 
				
			||||||
    to methods or attributes available on standard file handles.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `read_data` is a string for the `read` method of the file handle to return.
 | 
					 | 
				
			||||||
    This is an empty string by default.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Using `open` as a context manager is a great way to ensure your file handles
 | 
					 | 
				
			||||||
are closed properly and is becoming common::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    with open('/some/path', 'w') as f:
 | 
					 | 
				
			||||||
        f.write('something')
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The issue is that even if you mock out the call to `open` it is the
 | 
					 | 
				
			||||||
*returned object* that is used as a context manager (and has `__enter__` and
 | 
					 | 
				
			||||||
`__exit__` called).
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Mocking context managers with a :class:`MagicMock` is common enough and fiddly
 | 
					 | 
				
			||||||
enough that a helper function is useful.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> m = mock_open()
 | 
					 | 
				
			||||||
    >>> with patch('__main__.open', m, create=True):
 | 
					 | 
				
			||||||
    ...     with open('foo', 'w') as h:
 | 
					 | 
				
			||||||
    ...         h.write('some stuff')
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> m.mock_calls
 | 
					 | 
				
			||||||
    [call('foo', 'w'),
 | 
					 | 
				
			||||||
     call().__enter__(),
 | 
					 | 
				
			||||||
     call().write('some stuff'),
 | 
					 | 
				
			||||||
     call().__exit__(None, None, None)]
 | 
					 | 
				
			||||||
    >>> m.assert_called_once_with('foo', 'w')
 | 
					 | 
				
			||||||
    >>> handle = m()
 | 
					 | 
				
			||||||
    >>> handle.write.assert_called_once_with('some stuff')
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
And for reading files:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> with patch('__main__.open', mock_open(read_data='bibble'), create=True) as m:
 | 
					 | 
				
			||||||
    ...     with open('foo') as h:
 | 
					 | 
				
			||||||
    ...         result = h.read()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> m.assert_called_once_with('foo')
 | 
					 | 
				
			||||||
    >>> assert result == 'bibble'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. _auto-speccing:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Autospeccing
 | 
					 | 
				
			||||||
------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Autospeccing is based on the existing `spec` feature of mock. It limits the
 | 
					 | 
				
			||||||
api of mocks to the api of an original object (the spec), but it is recursive
 | 
					 | 
				
			||||||
(implemented lazily) so that attributes of mocks only have the same api as
 | 
					 | 
				
			||||||
the attributes of the spec. In addition mocked functions / methods have the
 | 
					 | 
				
			||||||
same call signature as the original so they raise a `TypeError` if they are
 | 
					 | 
				
			||||||
called incorrectly.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Before I explain how auto-speccing works, here's why it is needed.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`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 `Mock` api and the other is a more general problem with using
 | 
					 | 
				
			||||||
mock objects.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
First the problem specific to `Mock`. `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 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)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Your tests can pass silently and incorrectly because of the typo.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
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.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
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
 | 
					 | 
				
			||||||
don't test how your units are "wired together" there is still lots of room
 | 
					 | 
				
			||||||
for bugs that tests might have caught.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`mock` already provides a feature to help with this, called speccing. If you
 | 
					 | 
				
			||||||
use a class or instance as the `spec` for a mock then you can only access
 | 
					 | 
				
			||||||
attributes on the mock that exist on the real class:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> from urllib import request
 | 
					 | 
				
			||||||
    >>> mock = Mock(spec=request.Request)
 | 
					 | 
				
			||||||
    >>> mock.assret_called_with
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
    AttributeError: Mock object has no attribute 'assret_called_with'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The spec only applies to the mock itself, so we still have the same issue
 | 
					 | 
				
			||||||
with any methods on the mock:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. code-block:: pycon
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mock.has_data()
 | 
					 | 
				
			||||||
    <mock.Mock object at 0x...>
 | 
					 | 
				
			||||||
    >>> mock.has_data.assret_called_with()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Auto-speccing solves this problem. You can either pass `autospec=True` to
 | 
					 | 
				
			||||||
`patch` / `patch.object` or use the `create_autospec` function to create a
 | 
					 | 
				
			||||||
mock with a spec. If you use the `autospec=True` argument to `patch` then the
 | 
					 | 
				
			||||||
object that is being replaced will be used as the spec object. Because the
 | 
					 | 
				
			||||||
speccing is done "lazily" (the spec is created as attributes on the mock are
 | 
					 | 
				
			||||||
accessed) you can use it with very complex or deeply nested objects (like
 | 
					 | 
				
			||||||
modules that import modules that import modules) without a big performance
 | 
					 | 
				
			||||||
hit.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Here's an example of it in use:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> from urllib import request
 | 
					 | 
				
			||||||
    >>> patcher = patch('__main__.request', autospec=True)
 | 
					 | 
				
			||||||
    >>> mock_request = patcher.start()
 | 
					 | 
				
			||||||
    >>> request is mock_request
 | 
					 | 
				
			||||||
    True
 | 
					 | 
				
			||||||
    >>> mock_request.Request
 | 
					 | 
				
			||||||
    <MagicMock name='request.Request' spec='Request' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You can see that `request.Request` has a spec. `request.Request` takes two
 | 
					 | 
				
			||||||
arguments in the constructor (one of which is `self`). Here's what happens if
 | 
					 | 
				
			||||||
we try to call it incorrectly:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> req = request.Request()
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
    TypeError: <lambda>() takes at least 2 arguments (1 given)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The spec also applies to instantiated classes (i.e. the return value of
 | 
					 | 
				
			||||||
specced mocks):
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> req = request.Request('foo')
 | 
					 | 
				
			||||||
    >>> req
 | 
					 | 
				
			||||||
    <NonCallableMagicMock name='request.Request()' spec='Request' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`Request` objects are not callable, so the return value of instantiating our
 | 
					 | 
				
			||||||
mocked out `request.Request` is a non-callable mock. With the spec in place
 | 
					 | 
				
			||||||
any typos in our asserts will raise the correct error:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> req.add_header('spam', 'eggs')
 | 
					 | 
				
			||||||
    <MagicMock name='request.Request().add_header()' id='...'>
 | 
					 | 
				
			||||||
    >>> req.add_header.assret_called_with
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
    AttributeError: Mock object has no attribute 'assret_called_with'
 | 
					 | 
				
			||||||
    >>> req.add_header.assert_called_with('spam', 'eggs')
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
In many cases you will just be able to add `autospec=True` to your existing
 | 
					 | 
				
			||||||
`patch` calls and then be protected against bugs due to typos and api
 | 
					 | 
				
			||||||
changes.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
As well as using `autospec` through `patch` there is a
 | 
					 | 
				
			||||||
:func:`create_autospec` for creating autospecced mocks directly:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> from urllib import request
 | 
					 | 
				
			||||||
    >>> mock_request = create_autospec(request)
 | 
					 | 
				
			||||||
    >>> mock_request.Request('foo', 'bar')
 | 
					 | 
				
			||||||
    <NonCallableMagicMock name='mock.Request()' spec='Request' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
This isn't without caveats and limitations however, which is why it is not
 | 
					 | 
				
			||||||
the default behaviour. In order to know what attributes are available on the
 | 
					 | 
				
			||||||
spec object, autospec has to introspect (access attributes) the spec. As you
 | 
					 | 
				
			||||||
traverse attributes on the mock a corresponding traversal of the original
 | 
					 | 
				
			||||||
object is happening under the hood. If any of your specced objects have
 | 
					 | 
				
			||||||
properties or descriptors that can trigger code execution then you may not be
 | 
					 | 
				
			||||||
able to use autospec. On the other hand it is much better to design your
 | 
					 | 
				
			||||||
objects so that introspection is safe [#]_.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A more serious problem is that it is common for instance attributes to be
 | 
					 | 
				
			||||||
created in the `__init__` method and not to exist on the class at all.
 | 
					 | 
				
			||||||
`autospec` can't know about any dynamically created attributes and restricts
 | 
					 | 
				
			||||||
the api to visible attributes.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class Something(object):
 | 
					 | 
				
			||||||
    ...   def __init__(self):
 | 
					 | 
				
			||||||
    ...     self.a = 33
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> with patch('__main__.Something', autospec=True):
 | 
					 | 
				
			||||||
    ...   thing = Something()
 | 
					 | 
				
			||||||
    ...   thing.a
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
      ...
 | 
					 | 
				
			||||||
    AttributeError: Mock object has no attribute 'a'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
There are a few different ways of resolving this problem. The easiest, but
 | 
					 | 
				
			||||||
not necessarily the least annoying, way is to simply set the required
 | 
					 | 
				
			||||||
attributes on the mock after creation. Just because `autospec` doesn't allow
 | 
					 | 
				
			||||||
you to fetch attributes that don't exist on the spec it doesn't prevent you
 | 
					 | 
				
			||||||
setting them:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> with patch('__main__.Something', autospec=True):
 | 
					 | 
				
			||||||
    ...   thing = Something()
 | 
					 | 
				
			||||||
    ...   thing.a = 33
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
There is a more aggressive version of both `spec` and `autospec` that *does*
 | 
					 | 
				
			||||||
prevent you setting non-existent attributes. This is useful if you want to
 | 
					 | 
				
			||||||
ensure your code only *sets* valid attributes too, but obviously it prevents
 | 
					 | 
				
			||||||
this particular scenario:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> with patch('__main__.Something', autospec=True, spec_set=True):
 | 
					 | 
				
			||||||
    ...   thing = Something()
 | 
					 | 
				
			||||||
    ...   thing.a = 33
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
     ...
 | 
					 | 
				
			||||||
    AttributeError: Mock object has no attribute 'a'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Probably the best way of solving the problem is to add class attributes as
 | 
					 | 
				
			||||||
default values for instance members initialised in `__init__`. Note that if
 | 
					 | 
				
			||||||
you are only setting default attributes in `__init__` then providing them via
 | 
					 | 
				
			||||||
class attributes (shared between instances of course) is faster too. e.g.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. code-block:: python
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    class Something(object):
 | 
					 | 
				
			||||||
        a = 33
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
This brings up another issue. It is relatively common to provide a default
 | 
					 | 
				
			||||||
value of `None` for members that will later be an object of a different type.
 | 
					 | 
				
			||||||
`None` would be useless as a spec because it wouldn't let you access *any*
 | 
					 | 
				
			||||||
attributes or methods on it. As `None` is *never* going to be useful as a
 | 
					 | 
				
			||||||
spec, and probably indicates a member that will normally of some other type,
 | 
					 | 
				
			||||||
`autospec` doesn't use a spec for members that are set to `None`. These will
 | 
					 | 
				
			||||||
just be ordinary mocks (well - `MagicMocks`):
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class Something(object):
 | 
					 | 
				
			||||||
    ...     member = None
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> mock = create_autospec(Something)
 | 
					 | 
				
			||||||
    >>> mock.member.foo.bar.baz()
 | 
					 | 
				
			||||||
    <MagicMock name='mock.member.foo.bar.baz()' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If modifying your production classes to add defaults isn't to your liking
 | 
					 | 
				
			||||||
then there are more options. One of these is simply to use an instance as the
 | 
					 | 
				
			||||||
spec rather than the class. The other is to create a subclass of the
 | 
					 | 
				
			||||||
production class and add the defaults to the subclass without affecting the
 | 
					 | 
				
			||||||
production class. Both of these require you to use an alternative object as
 | 
					 | 
				
			||||||
the spec. Thankfully `patch` supports this - you can simply pass the
 | 
					 | 
				
			||||||
alternative object as the `autospec` argument:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class Something(object):
 | 
					 | 
				
			||||||
    ...   def __init__(self):
 | 
					 | 
				
			||||||
    ...     self.a = 33
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> class SomethingForTest(Something):
 | 
					 | 
				
			||||||
    ...   a = 33
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> p = patch('__main__.Something', autospec=SomethingForTest)
 | 
					 | 
				
			||||||
    >>> mock = p.start()
 | 
					 | 
				
			||||||
    >>> mock.a
 | 
					 | 
				
			||||||
    <NonCallableMagicMock name='Something.a' spec='int' id='...'>
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. [#] This only applies to classes or already instantiated objects. Calling
 | 
					 | 
				
			||||||
   a mocked class to create a mock instance *does not* create a real instance.
 | 
					 | 
				
			||||||
   It is only attribute lookups - along with calls to `dir` - that are done.
 | 
					 | 
				
			||||||
| 
						 | 
					@ -1,226 +0,0 @@
 | 
				
			||||||
:mod:`unittest.mock` --- MagicMock and magic method support
 | 
					 | 
				
			||||||
===========================================================
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. module:: unittest.mock
 | 
					 | 
				
			||||||
   :synopsis: Mock object library.
 | 
					 | 
				
			||||||
.. moduleauthor:: Michael Foord <michael@python.org>
 | 
					 | 
				
			||||||
.. currentmodule:: unittest.mock
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. versionadded:: 3.3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. _magic-methods:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Mocking Magic Methods
 | 
					 | 
				
			||||||
---------------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
:class:`Mock` supports mocking the Python protocol methods, also known as
 | 
					 | 
				
			||||||
"magic methods". This allows mock objects to replace containers or other
 | 
					 | 
				
			||||||
objects that implement Python protocols.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Because magic methods are looked up differently from normal methods [#]_, this
 | 
					 | 
				
			||||||
support has been specially implemented. This means that only specific magic
 | 
					 | 
				
			||||||
methods are supported. The supported list includes *almost* all of them. If
 | 
					 | 
				
			||||||
there are any missing that you need please let us know.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You mock magic methods by setting the method you are interested in to a function
 | 
					 | 
				
			||||||
or a mock instance. If you are using a function then it *must* take ``self`` as
 | 
					 | 
				
			||||||
the first argument [#]_.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> def __str__(self):
 | 
					 | 
				
			||||||
   ...     return 'fooble'
 | 
					 | 
				
			||||||
   ...
 | 
					 | 
				
			||||||
   >>> mock = Mock()
 | 
					 | 
				
			||||||
   >>> mock.__str__ = __str__
 | 
					 | 
				
			||||||
   >>> str(mock)
 | 
					 | 
				
			||||||
   'fooble'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock = Mock()
 | 
					 | 
				
			||||||
   >>> mock.__str__ = Mock()
 | 
					 | 
				
			||||||
   >>> mock.__str__.return_value = 'fooble'
 | 
					 | 
				
			||||||
   >>> str(mock)
 | 
					 | 
				
			||||||
   'fooble'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock = Mock()
 | 
					 | 
				
			||||||
   >>> mock.__iter__ = Mock(return_value=iter([]))
 | 
					 | 
				
			||||||
   >>> list(mock)
 | 
					 | 
				
			||||||
   []
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
One use case for this is for mocking objects used as context managers in a
 | 
					 | 
				
			||||||
`with` statement:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock = Mock()
 | 
					 | 
				
			||||||
   >>> mock.__enter__ = Mock(return_value='foo')
 | 
					 | 
				
			||||||
   >>> mock.__exit__ = Mock(return_value=False)
 | 
					 | 
				
			||||||
   >>> with mock as m:
 | 
					 | 
				
			||||||
   ...     assert m == 'foo'
 | 
					 | 
				
			||||||
   ...
 | 
					 | 
				
			||||||
   >>> mock.__enter__.assert_called_with()
 | 
					 | 
				
			||||||
   >>> mock.__exit__.assert_called_with(None, None, None)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Calls to magic methods do not appear in :attr:`~Mock.method_calls`, but they
 | 
					 | 
				
			||||||
are recorded in :attr:`~Mock.mock_calls`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. note::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   If you use the `spec` keyword argument to create a mock then attempting to
 | 
					 | 
				
			||||||
   set a magic method that isn't in the spec will raise an `AttributeError`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The full list of supported magic methods is:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* ``__hash__``, ``__sizeof__``, ``__repr__`` and ``__str__``
 | 
					 | 
				
			||||||
* ``__dir__``, ``__format__`` and ``__subclasses__``
 | 
					 | 
				
			||||||
* ``__floor__``, ``__trunc__`` and ``__ceil__``
 | 
					 | 
				
			||||||
* Comparisons: ``__cmp__``, ``__lt__``, ``__gt__``, ``__le__``, ``__ge__``,
 | 
					 | 
				
			||||||
  ``__eq__`` and ``__ne__``
 | 
					 | 
				
			||||||
* Container methods: ``__getitem__``, ``__setitem__``, ``__delitem__``,
 | 
					 | 
				
			||||||
  ``__contains__``, ``__len__``, ``__iter__``, ``__getslice__``,
 | 
					 | 
				
			||||||
  ``__setslice__``, ``__reversed__`` and ``__missing__``
 | 
					 | 
				
			||||||
* Context manager: ``__enter__`` and ``__exit__``
 | 
					 | 
				
			||||||
* Unary numeric methods: ``__neg__``, ``__pos__`` and ``__invert__``
 | 
					 | 
				
			||||||
* The numeric methods (including right hand and in-place variants):
 | 
					 | 
				
			||||||
  ``__add__``, ``__sub__``, ``__mul__``, ``__div__``,
 | 
					 | 
				
			||||||
  ``__floordiv__``, ``__mod__``, ``__divmod__``, ``__lshift__``,
 | 
					 | 
				
			||||||
  ``__rshift__``, ``__and__``, ``__xor__``, ``__or__``, and ``__pow__``
 | 
					 | 
				
			||||||
* Numeric conversion methods: ``__complex__``, ``__int__``, ``__float__``,
 | 
					 | 
				
			||||||
  ``__index__`` and ``__coerce__``
 | 
					 | 
				
			||||||
* Descriptor methods: ``__get__``, ``__set__`` and ``__delete__``
 | 
					 | 
				
			||||||
* Pickling: ``__reduce__``, ``__reduce_ex__``, ``__getinitargs__``,
 | 
					 | 
				
			||||||
  ``__getnewargs__``, ``__getstate__`` and ``__setstate__``
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The following methods exist but are *not* supported as they are either in use
 | 
					 | 
				
			||||||
by mock, can't be set dynamically, or can cause problems:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* ``__getattr__``, ``__setattr__``, ``__init__`` and ``__new__``
 | 
					 | 
				
			||||||
* ``__prepare__``, ``__instancecheck__``, ``__subclasscheck__``, ``__del__``
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Magic Mock
 | 
					 | 
				
			||||||
----------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
There are two `MagicMock` variants: `MagicMock` and `NonCallableMagicMock`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. class:: MagicMock(*args, **kw)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   ``MagicMock`` is a subclass of :class:`Mock` with default implementations
 | 
					 | 
				
			||||||
   of most of the magic methods. You can use ``MagicMock`` without having to
 | 
					 | 
				
			||||||
   configure the magic methods yourself.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   The constructor parameters have the same meaning as for :class:`Mock`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   If you use the `spec` or `spec_set` arguments then *only* magic methods
 | 
					 | 
				
			||||||
   that exist in the spec will be created.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. class:: NonCallableMagicMock(*args, **kw)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    A non-callable version of `MagicMock`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The constructor parameters have the same meaning as for
 | 
					 | 
				
			||||||
    :class:`MagicMock`, with the exception of `return_value` and
 | 
					 | 
				
			||||||
    `side_effect` which have no meaning on a non-callable mock.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The magic methods are setup with `MagicMock` objects, so you can configure them
 | 
					 | 
				
			||||||
and use them in the usual way:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock = MagicMock()
 | 
					 | 
				
			||||||
   >>> mock[3] = 'fish'
 | 
					 | 
				
			||||||
   >>> mock.__setitem__.assert_called_with(3, 'fish')
 | 
					 | 
				
			||||||
   >>> mock.__getitem__.return_value = 'result'
 | 
					 | 
				
			||||||
   >>> mock[2]
 | 
					 | 
				
			||||||
   'result'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
By default many of the protocol methods are required to return objects of a
 | 
					 | 
				
			||||||
specific type. These methods are preconfigured with a default return value, so
 | 
					 | 
				
			||||||
that they can be used without you having to do anything if you aren't interested
 | 
					 | 
				
			||||||
in the return value. You can still *set* the return value manually if you want
 | 
					 | 
				
			||||||
to change the default.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Methods and their defaults:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* ``__lt__``: NotImplemented
 | 
					 | 
				
			||||||
* ``__gt__``: NotImplemented
 | 
					 | 
				
			||||||
* ``__le__``: NotImplemented
 | 
					 | 
				
			||||||
* ``__ge__``: NotImplemented
 | 
					 | 
				
			||||||
* ``__int__`` : 1
 | 
					 | 
				
			||||||
* ``__contains__`` : False
 | 
					 | 
				
			||||||
* ``__len__`` : 1
 | 
					 | 
				
			||||||
* ``__iter__`` : iter([])
 | 
					 | 
				
			||||||
* ``__exit__`` : False
 | 
					 | 
				
			||||||
* ``__complex__`` : 1j
 | 
					 | 
				
			||||||
* ``__float__`` : 1.0
 | 
					 | 
				
			||||||
* ``__bool__`` : True
 | 
					 | 
				
			||||||
* ``__index__`` : 1
 | 
					 | 
				
			||||||
* ``__hash__`` : default hash for the mock
 | 
					 | 
				
			||||||
* ``__str__`` : default str for the mock
 | 
					 | 
				
			||||||
* ``__sizeof__``: default sizeof for the mock
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
For example:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock = MagicMock()
 | 
					 | 
				
			||||||
   >>> int(mock)
 | 
					 | 
				
			||||||
   1
 | 
					 | 
				
			||||||
   >>> len(mock)
 | 
					 | 
				
			||||||
   0
 | 
					 | 
				
			||||||
   >>> list(mock)
 | 
					 | 
				
			||||||
   []
 | 
					 | 
				
			||||||
   >>> object() in mock
 | 
					 | 
				
			||||||
   False
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The two equality method, `__eq__` and `__ne__`, are special.
 | 
					 | 
				
			||||||
They do the default equality comparison on identity, using a side
 | 
					 | 
				
			||||||
effect, unless you change their return value to return something else:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> MagicMock() == 3
 | 
					 | 
				
			||||||
   False
 | 
					 | 
				
			||||||
   >>> MagicMock() != 3
 | 
					 | 
				
			||||||
   True
 | 
					 | 
				
			||||||
   >>> mock = MagicMock()
 | 
					 | 
				
			||||||
   >>> mock.__eq__.return_value = True
 | 
					 | 
				
			||||||
   >>> mock == 3
 | 
					 | 
				
			||||||
   True
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The return value of `MagicMock.__iter__` can be any iterable object and isn't
 | 
					 | 
				
			||||||
required to be an iterator:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock = MagicMock()
 | 
					 | 
				
			||||||
   >>> mock.__iter__.return_value = ['a', 'b', 'c']
 | 
					 | 
				
			||||||
   >>> list(mock)
 | 
					 | 
				
			||||||
   ['a', 'b', 'c']
 | 
					 | 
				
			||||||
   >>> list(mock)
 | 
					 | 
				
			||||||
   ['a', 'b', 'c']
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If the return value *is* an iterator, then iterating over it once will consume
 | 
					 | 
				
			||||||
it and subsequent iterations will result in an empty list:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
   >>> mock.__iter__.return_value = iter(['a', 'b', 'c'])
 | 
					 | 
				
			||||||
   >>> list(mock)
 | 
					 | 
				
			||||||
   ['a', 'b', 'c']
 | 
					 | 
				
			||||||
   >>> list(mock)
 | 
					 | 
				
			||||||
   []
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
``MagicMock`` has all of the supported magic methods configured except for some
 | 
					 | 
				
			||||||
of the obscure and obsolete ones. You can still set these up if you want.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Magic methods that are supported but not setup by default in ``MagicMock`` are:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* ``__subclasses__``
 | 
					 | 
				
			||||||
* ``__dir__``
 | 
					 | 
				
			||||||
* ``__format__``
 | 
					 | 
				
			||||||
* ``__get__``, ``__set__`` and ``__delete__``
 | 
					 | 
				
			||||||
* ``__reversed__`` and ``__missing__``
 | 
					 | 
				
			||||||
* ``__reduce__``, ``__reduce_ex__``, ``__getinitargs__``, ``__getnewargs__``,
 | 
					 | 
				
			||||||
  ``__getstate__`` and ``__setstate__``
 | 
					 | 
				
			||||||
* ``__getformat__`` and ``__setformat__``
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. [#] Magic methods *should* be looked up on the class rather than the
 | 
					 | 
				
			||||||
   instance. Different versions of Python are inconsistent about applying this
 | 
					 | 
				
			||||||
   rule. The supported protocol methods should work with all supported versions
 | 
					 | 
				
			||||||
   of Python.
 | 
					 | 
				
			||||||
.. [#] The function is basically hooked up to the class, but each ``Mock``
 | 
					 | 
				
			||||||
   instance is kept isolated from the others.
 | 
					 | 
				
			||||||
| 
						 | 
					@ -1,538 +0,0 @@
 | 
				
			||||||
:mod:`unittest.mock` --- the patchers
 | 
					 | 
				
			||||||
=====================================
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. module:: unittest.mock
 | 
					 | 
				
			||||||
   :synopsis: Mock object library.
 | 
					 | 
				
			||||||
.. moduleauthor:: Michael Foord <michael@python.org>
 | 
					 | 
				
			||||||
.. currentmodule:: unittest.mock
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. versionadded:: 3.3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The patch decorators are used for patching objects only within the scope of
 | 
					 | 
				
			||||||
the function they decorate. They automatically handle the unpatching for you,
 | 
					 | 
				
			||||||
even if exceptions are raised. All of these functions can also be used in with
 | 
					 | 
				
			||||||
statements or as class decorators.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
patch
 | 
					 | 
				
			||||||
-----
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. note::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch` is straightforward to use. The key is to do the patching in the
 | 
					 | 
				
			||||||
    right namespace. See the section `where to patch`_.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: patch(target, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch` acts as a function decorator, class decorator or a context
 | 
					 | 
				
			||||||
    manager. Inside the body of the function or with statement, the `target`
 | 
					 | 
				
			||||||
    (specified in the form `'package.module.ClassName'`) is patched
 | 
					 | 
				
			||||||
    with a `new` object. When the function/with statement exits the patch is
 | 
					 | 
				
			||||||
    undone.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The `target` is imported and the specified attribute patched with the new
 | 
					 | 
				
			||||||
    object, so it must be importable from the environment you are calling the
 | 
					 | 
				
			||||||
    decorator from. The target is imported when the decorated function is
 | 
					 | 
				
			||||||
    executed, not at decoration time.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    If `new` is omitted, then a new `MagicMock` is created and passed in as an
 | 
					 | 
				
			||||||
    extra argument to the decorated function.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The `spec` and `spec_set` keyword arguments are passed to the `MagicMock`
 | 
					 | 
				
			||||||
    if patch is creating one for you.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    In addition you can pass `spec=True` or `spec_set=True`, which causes
 | 
					 | 
				
			||||||
    patch to pass in the object being mocked as the spec/spec_set object.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `new_callable` allows you to specify a different class, or callable object,
 | 
					 | 
				
			||||||
    that will be called to create the `new` object. By default `MagicMock` is
 | 
					 | 
				
			||||||
    used.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    A more powerful form of `spec` is `autospec`. If you set `autospec=True`
 | 
					 | 
				
			||||||
    then the mock with be created with a spec from the object being replaced.
 | 
					 | 
				
			||||||
    All attributes of the mock will also have the spec of the corresponding
 | 
					 | 
				
			||||||
    attribute of the object being replaced. Methods and functions being mocked
 | 
					 | 
				
			||||||
    will have their arguments checked and will raise a `TypeError` if they are
 | 
					 | 
				
			||||||
    called with the wrong signature. For mocks
 | 
					 | 
				
			||||||
    replacing a class, their return value (the 'instance') will have the same
 | 
					 | 
				
			||||||
    spec as the class. See the :func:`create_autospec` function and
 | 
					 | 
				
			||||||
    :ref:`auto-speccing`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Instead of `autospec=True` you can pass `autospec=some_object` to use an
 | 
					 | 
				
			||||||
    arbitrary object as the spec instead of the one being replaced.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    By default `patch` will fail to replace attributes that don't exist. If
 | 
					 | 
				
			||||||
    you pass in `create=True`, and the attribute doesn't exist, patch will
 | 
					 | 
				
			||||||
    create the attribute for you when the patched function is called, and
 | 
					 | 
				
			||||||
    delete it again afterwards. This is useful for writing tests against
 | 
					 | 
				
			||||||
    attributes that your production code creates at runtime. It is off by by
 | 
					 | 
				
			||||||
    default because it can be dangerous. With it switched on you can write
 | 
					 | 
				
			||||||
    passing tests against APIs that don't actually exist!
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Patch can be used as a `TestCase` class decorator. It works by
 | 
					 | 
				
			||||||
    decorating each test method in the class. This reduces the boilerplate
 | 
					 | 
				
			||||||
    code when your test methods share a common patchings set. `patch` finds
 | 
					 | 
				
			||||||
    tests by looking for method names that start with `patch.TEST_PREFIX`.
 | 
					 | 
				
			||||||
    By default this is `test`, which matches the way `unittest` finds tests.
 | 
					 | 
				
			||||||
    You can specify an alternative prefix by setting `patch.TEST_PREFIX`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Patch can be used as a context manager, with the with statement. Here the
 | 
					 | 
				
			||||||
    patching applies to the indented block after the with statement. If you
 | 
					 | 
				
			||||||
    use "as" then the patched object will be bound to the name after the
 | 
					 | 
				
			||||||
    "as"; very useful if `patch` is creating a mock object for you.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch` takes arbitrary keyword arguments. These will be passed to
 | 
					 | 
				
			||||||
    the `Mock` (or `new_callable`) on construction.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch.dict(...)`, `patch.multiple(...)` and `patch.object(...)` are
 | 
					 | 
				
			||||||
    available for alternate use-cases.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Patching a class replaces the class with a `MagicMock` *instance*. If the
 | 
					 | 
				
			||||||
class is instantiated in the code under test then it will be the
 | 
					 | 
				
			||||||
:attr:`~Mock.return_value` of the mock that will be used.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If the class is instantiated multiple times you could use
 | 
					 | 
				
			||||||
:attr:`~Mock.side_effect` to return a new mock each time. Alternatively you
 | 
					 | 
				
			||||||
can set the `return_value` to be anything you want.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
To configure return values on methods of *instances* on the patched class
 | 
					 | 
				
			||||||
you must do this on the `return_value`. For example:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class Class(object):
 | 
					 | 
				
			||||||
    ...     def method(self):
 | 
					 | 
				
			||||||
    ...         pass
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> with patch('__main__.Class') as MockClass:
 | 
					 | 
				
			||||||
    ...     instance = MockClass.return_value
 | 
					 | 
				
			||||||
    ...     instance.method.return_value = 'foo'
 | 
					 | 
				
			||||||
    ...     assert Class() is instance
 | 
					 | 
				
			||||||
    ...     assert Class().method() == 'foo'
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you use `spec` or `spec_set` and `patch` is replacing a *class*, then the
 | 
					 | 
				
			||||||
return value of the created mock will have the same spec.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> Original = Class
 | 
					 | 
				
			||||||
    >>> patcher = patch('__main__.Class', spec=True)
 | 
					 | 
				
			||||||
    >>> MockClass = patcher.start()
 | 
					 | 
				
			||||||
    >>> instance = MockClass()
 | 
					 | 
				
			||||||
    >>> assert isinstance(instance, Original)
 | 
					 | 
				
			||||||
    >>> patcher.stop()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The `new_callable` argument is useful where you want to use an alternative
 | 
					 | 
				
			||||||
class to the default :class:`MagicMock` for the created mock. For example, if
 | 
					 | 
				
			||||||
you wanted a :class:`NonCallableMock` to be used:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> thing = object()
 | 
					 | 
				
			||||||
    >>> with patch('__main__.thing', new_callable=NonCallableMock) as mock_thing:
 | 
					 | 
				
			||||||
    ...     assert thing is mock_thing
 | 
					 | 
				
			||||||
    ...     thing()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
      ...
 | 
					 | 
				
			||||||
    TypeError: 'NonCallableMock' object is not callable
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Another use case might be to replace an object with a `StringIO` instance:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> from StringIO import StringIO
 | 
					 | 
				
			||||||
    >>> def foo():
 | 
					 | 
				
			||||||
    ...     print 'Something'
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> @patch('sys.stdout', new_callable=StringIO)
 | 
					 | 
				
			||||||
    ... def test(mock_stdout):
 | 
					 | 
				
			||||||
    ...     foo()
 | 
					 | 
				
			||||||
    ...     assert mock_stdout.getvalue() == 'Something\n'
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
When `patch` is creating a mock for you, it is common that the first thing
 | 
					 | 
				
			||||||
you need to do is to configure the mock. Some of that configuration can be done
 | 
					 | 
				
			||||||
in the call to patch. Any arbitrary keywords you pass into the call will be
 | 
					 | 
				
			||||||
used to set attributes on the created mock:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> patcher = patch('__main__.thing', first='one', second='two')
 | 
					 | 
				
			||||||
    >>> mock_thing = patcher.start()
 | 
					 | 
				
			||||||
    >>> mock_thing.first
 | 
					 | 
				
			||||||
    'one'
 | 
					 | 
				
			||||||
    >>> mock_thing.second
 | 
					 | 
				
			||||||
    'two'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
As well as attributes on the created mock attributes, like the
 | 
					 | 
				
			||||||
:attr:`~Mock.return_value` and :attr:`~Mock.side_effect`, of child mocks can
 | 
					 | 
				
			||||||
also be configured. These aren't syntactically valid to pass in directly as
 | 
					 | 
				
			||||||
keyword arguments, but a dictionary with these as keys can still be expanded
 | 
					 | 
				
			||||||
into a `patch` call using `**`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> config = {'method.return_value': 3, 'other.side_effect': KeyError}
 | 
					 | 
				
			||||||
    >>> patcher = patch('__main__.thing', **config)
 | 
					 | 
				
			||||||
    >>> mock_thing = patcher.start()
 | 
					 | 
				
			||||||
    >>> mock_thing.method()
 | 
					 | 
				
			||||||
    3
 | 
					 | 
				
			||||||
    >>> mock_thing.other()
 | 
					 | 
				
			||||||
    Traceback (most recent call last):
 | 
					 | 
				
			||||||
      ...
 | 
					 | 
				
			||||||
    KeyError
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
patch.object
 | 
					 | 
				
			||||||
------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: patch.object(target, attribute, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    patch the named member (`attribute`) on an object (`target`) with a mock
 | 
					 | 
				
			||||||
    object.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch.object` can be used as a decorator, class decorator or a context
 | 
					 | 
				
			||||||
    manager. Arguments `new`, `spec`, `create`, `spec_set`, `autospec` and
 | 
					 | 
				
			||||||
    `new_callable` have the same meaning as for `patch`. Like `patch`,
 | 
					 | 
				
			||||||
    `patch.object` takes arbitrary keyword arguments for configuring the mock
 | 
					 | 
				
			||||||
    object it creates.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    When used as a class decorator `patch.object` honours `patch.TEST_PREFIX`
 | 
					 | 
				
			||||||
    for choosing which methods to wrap.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You can either call `patch.object` with three arguments or two arguments. The
 | 
					 | 
				
			||||||
three argument form takes the object to be patched, the attribute name and the
 | 
					 | 
				
			||||||
object to replace the attribute with.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
When calling with the two argument form you omit the replacement object, and a
 | 
					 | 
				
			||||||
mock is created for you and passed in as an extra argument to the decorated
 | 
					 | 
				
			||||||
function:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> @patch.object(SomeClass, 'class_method')
 | 
					 | 
				
			||||||
    ... def test(mock_method):
 | 
					 | 
				
			||||||
    ...     SomeClass.class_method(3)
 | 
					 | 
				
			||||||
    ...     mock_method.assert_called_with(3)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`spec`, `create` and the other arguments to `patch.object` have the same
 | 
					 | 
				
			||||||
meaning as they do for `patch`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
patch.dict
 | 
					 | 
				
			||||||
----------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: patch.dict(in_dict, values=(), clear=False, **kwargs)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Patch a dictionary, or dictionary like object, and restore the dictionary
 | 
					 | 
				
			||||||
    to its original state after the test.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `in_dict` can be a dictionary or a mapping like container. If it is a
 | 
					 | 
				
			||||||
    mapping then it must at least support getting, setting and deleting items
 | 
					 | 
				
			||||||
    plus iterating over keys.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `in_dict` can also be a string specifying the name of the dictionary, which
 | 
					 | 
				
			||||||
    will then be fetched by importing it.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `values` can be a dictionary of values to set in the dictionary. `values`
 | 
					 | 
				
			||||||
    can also be an iterable of `(key, value)` pairs.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    If `clear` is True then the dictionary will be cleared before the new
 | 
					 | 
				
			||||||
    values are set.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch.dict` can also be called with arbitrary keyword arguments to set
 | 
					 | 
				
			||||||
    values in the dictionary.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch.dict` can be used as a context manager, decorator or class
 | 
					 | 
				
			||||||
    decorator. When used as a class decorator `patch.dict` honours
 | 
					 | 
				
			||||||
    `patch.TEST_PREFIX` for choosing which methods to wrap.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`patch.dict` can be used to add members to a dictionary, or simply let a test
 | 
					 | 
				
			||||||
change a dictionary, and ensure the dictionary is restored when the test
 | 
					 | 
				
			||||||
ends.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> foo = {}
 | 
					 | 
				
			||||||
    >>> with patch.dict(foo, {'newkey': 'newvalue'}):
 | 
					 | 
				
			||||||
    ...     assert foo == {'newkey': 'newvalue'}
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> assert foo == {}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> import os
 | 
					 | 
				
			||||||
    >>> with patch.dict('os.environ', {'newkey': 'newvalue'}):
 | 
					 | 
				
			||||||
    ...     print os.environ['newkey']
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    newvalue
 | 
					 | 
				
			||||||
    >>> assert 'newkey' not in os.environ
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Keywords can be used in the `patch.dict` call to set values in the dictionary:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> mymodule = MagicMock()
 | 
					 | 
				
			||||||
    >>> mymodule.function.return_value = 'fish'
 | 
					 | 
				
			||||||
    >>> with patch.dict('sys.modules', mymodule=mymodule):
 | 
					 | 
				
			||||||
    ...     import mymodule
 | 
					 | 
				
			||||||
    ...     mymodule.function('some', 'args')
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    'fish'
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`patch.dict` can be used with dictionary like objects that aren't actually
 | 
					 | 
				
			||||||
dictionaries. At the very minimum they must support item getting, setting,
 | 
					 | 
				
			||||||
deleting and either iteration or membership test. This corresponds to the
 | 
					 | 
				
			||||||
magic methods `__getitem__`, `__setitem__`, `__delitem__` and either
 | 
					 | 
				
			||||||
`__iter__` or `__contains__`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class Container(object):
 | 
					 | 
				
			||||||
    ...     def __init__(self):
 | 
					 | 
				
			||||||
    ...         self.values = {}
 | 
					 | 
				
			||||||
    ...     def __getitem__(self, name):
 | 
					 | 
				
			||||||
    ...         return self.values[name]
 | 
					 | 
				
			||||||
    ...     def __setitem__(self, name, value):
 | 
					 | 
				
			||||||
    ...         self.values[name] = value
 | 
					 | 
				
			||||||
    ...     def __delitem__(self, name):
 | 
					 | 
				
			||||||
    ...         del self.values[name]
 | 
					 | 
				
			||||||
    ...     def __iter__(self):
 | 
					 | 
				
			||||||
    ...         return iter(self.values)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> thing = Container()
 | 
					 | 
				
			||||||
    >>> thing['one'] = 1
 | 
					 | 
				
			||||||
    >>> with patch.dict(thing, one=2, two=3):
 | 
					 | 
				
			||||||
    ...     assert thing['one'] == 2
 | 
					 | 
				
			||||||
    ...     assert thing['two'] == 3
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> assert thing['one'] == 1
 | 
					 | 
				
			||||||
    >>> assert list(thing) == ['one']
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
patch.multiple
 | 
					 | 
				
			||||||
--------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. function:: patch.multiple(target, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Perform multiple patches in a single call. It takes the object to be
 | 
					 | 
				
			||||||
    patched (either as an object or a string to fetch the object by importing)
 | 
					 | 
				
			||||||
    and keyword arguments for the patches::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
        with patch.multiple(settings, FIRST_PATCH='one', SECOND_PATCH='two'):
 | 
					 | 
				
			||||||
            ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Use :data:`DEFAULT` as the value if you want `patch.multiple` to create
 | 
					 | 
				
			||||||
    mocks for you. In this case the created mocks are passed into a decorated
 | 
					 | 
				
			||||||
    function by keyword, and a dictionary is returned when `patch.multiple` is
 | 
					 | 
				
			||||||
    used as a context manager.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    `patch.multiple` can be used as a decorator, class decorator or a context
 | 
					 | 
				
			||||||
    manager. The arguments `spec`, `spec_set`, `create`, `autospec` and
 | 
					 | 
				
			||||||
    `new_callable` have the same meaning as for `patch`. These arguments will
 | 
					 | 
				
			||||||
    be applied to *all* patches done by `patch.multiple`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    When used as a class decorator `patch.multiple` honours `patch.TEST_PREFIX`
 | 
					 | 
				
			||||||
    for choosing which methods to wrap.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you want `patch.multiple` to create mocks for you, then you can use
 | 
					 | 
				
			||||||
:data:`DEFAULT` as the value. If you use `patch.multiple` as a decorator
 | 
					 | 
				
			||||||
then the created mocks are passed into the decorated function by keyword.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> thing = object()
 | 
					 | 
				
			||||||
    >>> other = object()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
 | 
					 | 
				
			||||||
    ... def test_function(thing, other):
 | 
					 | 
				
			||||||
    ...     assert isinstance(thing, MagicMock)
 | 
					 | 
				
			||||||
    ...     assert isinstance(other, MagicMock)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test_function()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`patch.multiple` can be nested with other `patch` decorators, but put arguments
 | 
					 | 
				
			||||||
passed by keyword *after* any of the standard arguments created by `patch`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> @patch('sys.exit')
 | 
					 | 
				
			||||||
    ... @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
 | 
					 | 
				
			||||||
    ... def test_function(mock_exit, other, thing):
 | 
					 | 
				
			||||||
    ...     assert 'other' in repr(other)
 | 
					 | 
				
			||||||
    ...     assert 'thing' in repr(thing)
 | 
					 | 
				
			||||||
    ...     assert 'exit' in repr(mock_exit)
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> test_function()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If `patch.multiple` is used as a context manager, the value returned by the
 | 
					 | 
				
			||||||
context manger is a dictionary where created mocks are keyed by name:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> with patch.multiple('__main__', thing=DEFAULT, other=DEFAULT) as values:
 | 
					 | 
				
			||||||
    ...     assert 'other' in repr(values['other'])
 | 
					 | 
				
			||||||
    ...     assert 'thing' in repr(values['thing'])
 | 
					 | 
				
			||||||
    ...     assert values['thing'] is thing
 | 
					 | 
				
			||||||
    ...     assert values['other'] is other
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. _start-and-stop:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
patch methods: start and stop
 | 
					 | 
				
			||||||
-----------------------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
All the patchers have `start` and `stop` methods. These make it simpler to do
 | 
					 | 
				
			||||||
patching in `setUp` methods or where you want to do multiple patches without
 | 
					 | 
				
			||||||
nesting decorators or with statements.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
To use them call `patch`, `patch.object` or `patch.dict` as normal and keep a
 | 
					 | 
				
			||||||
reference to the returned `patcher` object. You can then call `start` to put
 | 
					 | 
				
			||||||
the patch in place and `stop` to undo it.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you are using `patch` to create a mock for you then it will be returned by
 | 
					 | 
				
			||||||
the call to `patcher.start`.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> patcher = patch('package.module.ClassName')
 | 
					 | 
				
			||||||
    >>> from package import module
 | 
					 | 
				
			||||||
    >>> original = module.ClassName
 | 
					 | 
				
			||||||
    >>> new_mock = patcher.start()
 | 
					 | 
				
			||||||
    >>> assert module.ClassName is not original
 | 
					 | 
				
			||||||
    >>> assert module.ClassName is new_mock
 | 
					 | 
				
			||||||
    >>> patcher.stop()
 | 
					 | 
				
			||||||
    >>> assert module.ClassName is original
 | 
					 | 
				
			||||||
    >>> assert module.ClassName is not new_mock
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
A typical use case for this might be for doing multiple patches in the `setUp`
 | 
					 | 
				
			||||||
method of a `TestCase`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> class MyTest(TestCase):
 | 
					 | 
				
			||||||
    ...     def setUp(self):
 | 
					 | 
				
			||||||
    ...         self.patcher1 = patch('package.module.Class1')
 | 
					 | 
				
			||||||
    ...         self.patcher2 = patch('package.module.Class2')
 | 
					 | 
				
			||||||
    ...         self.MockClass1 = self.patcher1.start()
 | 
					 | 
				
			||||||
    ...         self.MockClass2 = self.patcher2.start()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    ...     def tearDown(self):
 | 
					 | 
				
			||||||
    ...         self.patcher1.stop()
 | 
					 | 
				
			||||||
    ...         self.patcher2.stop()
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    ...     def test_something(self):
 | 
					 | 
				
			||||||
    ...         assert package.module.Class1 is self.MockClass1
 | 
					 | 
				
			||||||
    ...         assert package.module.Class2 is self.MockClass2
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> MyTest('test_something').run()
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. caution::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    If you use this technique you must ensure that the patching is "undone" by
 | 
					 | 
				
			||||||
    calling `stop`. This can be fiddlier than you might think, because if an
 | 
					 | 
				
			||||||
    exception is raised in the ``setUp`` then ``tearDown`` is not called.
 | 
					 | 
				
			||||||
    :meth:`unittest.TestCase.addCleanup` makes this easier:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
        >>> class MyTest(TestCase):
 | 
					 | 
				
			||||||
        ...     def setUp(self):
 | 
					 | 
				
			||||||
        ...         patcher = patch('package.module.Class')
 | 
					 | 
				
			||||||
        ...         self.MockClass = patcher.start()
 | 
					 | 
				
			||||||
        ...         self.addCleanup(patcher.stop)
 | 
					 | 
				
			||||||
        ...
 | 
					 | 
				
			||||||
        ...     def test_something(self):
 | 
					 | 
				
			||||||
        ...         assert package.module.Class is self.MockClass
 | 
					 | 
				
			||||||
        ...
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    As an added bonus you no longer need to keep a reference to the `patcher`
 | 
					 | 
				
			||||||
    object.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
In fact `start` and `stop` are just aliases for the context manager
 | 
					 | 
				
			||||||
`__enter__` and `__exit__` methods.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
TEST_PREFIX
 | 
					 | 
				
			||||||
-----------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
All of the patchers can be used as class decorators. When used in this way
 | 
					 | 
				
			||||||
they wrap every test method on the class. The patchers recognise methods that
 | 
					 | 
				
			||||||
start with `test` as being test methods. This is the same way that the
 | 
					 | 
				
			||||||
:class:`unittest.TestLoader` finds test methods by default.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
It is possible that you want to use a different prefix for your tests. You can
 | 
					 | 
				
			||||||
inform the patchers of the different prefix by setting `patch.TEST_PREFIX`:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> patch.TEST_PREFIX = 'foo'
 | 
					 | 
				
			||||||
    >>> value = 3
 | 
					 | 
				
			||||||
    >>>
 | 
					 | 
				
			||||||
    >>> @patch('__main__.value', 'not three')
 | 
					 | 
				
			||||||
    ... class Thing(object):
 | 
					 | 
				
			||||||
    ...     def foo_one(self):
 | 
					 | 
				
			||||||
    ...         print value
 | 
					 | 
				
			||||||
    ...     def foo_two(self):
 | 
					 | 
				
			||||||
    ...         print value
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>>
 | 
					 | 
				
			||||||
    >>> Thing().foo_one()
 | 
					 | 
				
			||||||
    not three
 | 
					 | 
				
			||||||
    >>> Thing().foo_two()
 | 
					 | 
				
			||||||
    not three
 | 
					 | 
				
			||||||
    >>> value
 | 
					 | 
				
			||||||
    3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Nesting Patch Decorators
 | 
					 | 
				
			||||||
------------------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If you want to perform multiple patches then you can simply stack up the
 | 
					 | 
				
			||||||
decorators.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
You can stack up multiple patch decorators using this pattern:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    >>> @patch.object(SomeClass, 'class_method')
 | 
					 | 
				
			||||||
    ... @patch.object(SomeClass, 'static_method')
 | 
					 | 
				
			||||||
    ... def test(mock1, mock2):
 | 
					 | 
				
			||||||
    ...     assert SomeClass.static_method is mock1
 | 
					 | 
				
			||||||
    ...     assert SomeClass.class_method is mock2
 | 
					 | 
				
			||||||
    ...     SomeClass.static_method('foo')
 | 
					 | 
				
			||||||
    ...     SomeClass.class_method('bar')
 | 
					 | 
				
			||||||
    ...     return mock1, mock2
 | 
					 | 
				
			||||||
    ...
 | 
					 | 
				
			||||||
    >>> mock1, mock2 = test()
 | 
					 | 
				
			||||||
    >>> mock1.assert_called_once_with('foo')
 | 
					 | 
				
			||||||
    >>> mock2.assert_called_once_with('bar')
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Note that the decorators are applied from the bottom upwards. This is the
 | 
					 | 
				
			||||||
standard way that Python applies decorators. The order of the created mocks
 | 
					 | 
				
			||||||
passed into your test function matches this order.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.. _where-to-patch:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Where to patch
 | 
					 | 
				
			||||||
--------------
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
`patch` works by (temporarily) changing the object that a *name* points to with
 | 
					 | 
				
			||||||
another one. There can be many names pointing to any individual object, so
 | 
					 | 
				
			||||||
for patching to work you must ensure that you patch the name used by the system
 | 
					 | 
				
			||||||
under test.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The basic principle is that you patch where an object is *looked up*, which
 | 
					 | 
				
			||||||
is not necessarily the same place as where it is defined. A couple of
 | 
					 | 
				
			||||||
examples will help to clarify this.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Imagine we have a project that we want to test with the following structure::
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    a.py
 | 
					 | 
				
			||||||
        -> Defines SomeClass
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    b.py
 | 
					 | 
				
			||||||
        -> from a import SomeClass
 | 
					 | 
				
			||||||
        -> some_function instantiates SomeClass
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Now we want to test `some_function` but we want to mock out `SomeClass` using
 | 
					 | 
				
			||||||
`patch`. The problem is that when we import module b, which we will have to
 | 
					 | 
				
			||||||
do then it imports `SomeClass` from module a. If we use `patch` to mock out
 | 
					 | 
				
			||||||
`a.SomeClass` then it will have no effect on our test; module b already has a
 | 
					 | 
				
			||||||
reference to the *real* `SomeClass` and it looks like our patching had no
 | 
					 | 
				
			||||||
effect.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The key is to patch out `SomeClass` where it is used (or where it is looked up
 | 
					 | 
				
			||||||
). In this case `some_function` will actually look up `SomeClass` in module b,
 | 
					 | 
				
			||||||
where we have imported it. The patching should look like::
 | 
					 | 
				
			||||||
 | 
					 | 
				
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    @patch('b.SomeClass')
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However, consider the alternative scenario where instead of `from a import
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SomeClass` module b does `import a` and `some_function` uses `a.SomeClass`. Both
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of these import forms are common. In this case the class we want to patch is
 | 
					 | 
				
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being looked up on the a module and so we have to patch `a.SomeClass` instead::
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    @patch('a.SomeClass')
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Patching Descriptors and Proxy Objects
 | 
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--------------------------------------
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Both patch_ and patch.object_ correctly patch and restore descriptors: class
 | 
					 | 
				
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methods, static methods and properties. You should patch these on the *class*
 | 
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rather than an instance. They also work with *some* objects
 | 
					 | 
				
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that proxy attribute access, like the `django setttings object
 | 
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<http://www.voidspace.org.uk/python/weblog/arch_d7_2010_12_04.shtml#e1198>`_.
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