How to verify mock method not called in python?

Question

In my code I am using assert_any_call() to verify series of call that happens to the django model filter, Now I need to verify the reverse case of this like assert_not_called(args).

Is there any assert statement to achieve this in python?

Answer 1

The simplest way is to use Mock.call_args_list :

assert call(None, a=1, b="") not in mocked_func.call_args_list, "Called with invalid args."

If you want a method, use:

class NotCalledMagicMock(unittest.mock.MagicMock):
    def assert_not_called(_mock_self, *args, **kwargs):
        self = _mock_self
        if self.call_args is None:
            return

        expected = self._call_matcher((args, kwargs))
        if any(self._call_matcher(ca) == expected for ca in self.call_args_list):
            cause = expected if isinstance(expected, Exception) else None
            raise AssertionError(
                '%r found in call list' % (self._format_mock_call_signature(args, kwargs),)
            ) from cause

To use this class, put this decorator before your test function:

@unittest.mock.patch("unittest.mock.MagicMock", NotCalledMagicMock)

Or make your mocks using:

func_b_mock = NotCalledMagicMock()

To use the method (where func_b_mock is a mock generated by eg patch ):

func_b_mock.assert_not_called([12], a=4)

When it fails, it raises an AssertionError like:

Traceback (most recent call last):
  File "your_test.py", line 34, in <module>
    test_a()
  File "/usr/lib/python3.4/unittest/mock.py", line 1136, in patched
    return func(*args, **keywargs)
  File "your_test.py", line 33, in test_a
    func_b_mock.assert_not_called([1])
  File "your_test.py", line 20, in assert_not_called
    ) from cause
AssertionError: 'func_b([1])' found in call list