stuff.py

class TestSuite:
  
    @patch('real_class_name')
    def test_case(self, mock_class):
        # Delay the evaluation of Mock() so that we get
        # a new mock object for each time the (mocked) 
        # class constructor is called.
        def new_mock_obj(*args, **kwargs):
            mock_obj = Mock()
            mock_obj.some_function.return_value = 'w00t'
            return mock_obj

        # If we wrote mock_class.return_value = Mock() here
        # then our assertion at the bottom would fail.
        mock_class.side_effect = new_mock_obj
        
        mock_objs = []
        
        for i in range(0, 3):
          mock_obj = mock_class()
          mock_obj.some_function()
          mock_objs.add(mock_obj)
        
        for mock_obj in mock_objs:
          assert mock_obj.some_function.call_count == 1