__dir__() Mock objects limit the results of dir(some_mock) to useful results. For mocks with a spec this includes all the permitted attributes for the mock. See FILTER_DIR for what this filtering does, and how to switch it off.

__class__ Normally the __class__ attribute of an object will return its type. For a mock object with a spec, __class__ returns the spec class instead. This allows mock objects to pass isinstance() tests for the object they are replacing / masquerading as: >>> mock = Mock(spec=3) >>> isinstance(mock, int) True __class__ is assignable to, this allows a mock to pass an isinstance() check without forcing you to use a spec: >>> mock = Mock() >>> mock.__class__

_get_child_mock(**kw) Create the child mocks for attributes and return value. By default child mocks will be the same type as the parent. Subclasses of Mock may want to override this to customize the way child mocks are made. For non-callable mocks the callable variant will be used (rather than any custom subclass).

side_effect This can either be a function to be called when the mock is called, an iterable or an exception (class or instance) to be raised. If you pass in a function it will be called with same arguments as the mock and unless the function returns the DEFAULT singleton the call to the mock will then return whatever the function returns. If the function returns DEFAULT then the mock will return its normal value (from the return_value). If you pass in an iterable, it is used to retrieve an i

return_value Set this to configure the value returned by calling the mock: >>> mock = Mock() >>> mock.return_value = 'fish' >>> mock() 'fish' The default return value is a mock object and you can configure it in the normal way: >>> mock = Mock() >>> mock.return_value.attribute = sentinel.Attribute >>> mock.return_value() <Mock name='mock()()' id='...'> >>> mock.return_value.assert_called_with() return_value can also be se

reset_mock() The reset_mock method resets all the call attributes on a mock object: >>> mock = Mock(return_value=None) >>> mock('hello') >>> mock.called True >>> mock.reset_mock() >>> mock.called False This can be useful where you want to make a series of assertions that reuse the same object. Note that reset_mock() doesn’t clear the return value, side_effect or any child attributes you have set using normal assignment. Child mocks and the return

mock_calls mock_calls records all calls to the mock object, its methods, magic methods and return value mocks. >>> mock = MagicMock() >>> result = mock(1, 2, 3) >>> mock.first(a=3) <MagicMock name='mock.first()' id='...'> >>> mock.second() <MagicMock name='mock.second()' id='...'> >>> int(mock) 1 >>> result(1) <MagicMock name='mock()()' id='...'> >>> expected = [call(1, 2, 3), call.first(a=3), call.second(), ...

mock_add_spec(spec, spec_set=False) Add a spec to a mock. spec can either be an object or a list of strings. Only attributes on the spec can be fetched as attributes from the mock. If spec_set is true then only attributes on the spec can be set.

method_calls As well as tracking calls to themselves, mocks also track calls to methods and attributes, and their methods and attributes: >>> mock = Mock() >>> mock.method() <Mock name='mock.method()' id='...'> >>> mock.property.method.attribute() <Mock name='mock.property.method.attribute()' id='...'> >>> mock.method_calls [call.method(), call.property.method.attribute()] Members of method_calls are call objects. These can be unpacked as tupl

configure_mock(**kwargs) Set attributes on the mock through keyword arguments. Attributes plus return values and side effects can be set on child mocks using standard dot notation and unpacking a dictionary in the method call: >>> mock = Mock() >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError} >>> mock.configure_mock(**attrs) >>> mock.method() 3 >>> mock.other() Traceback (most recent call last): ... KeyError The same thing