def test_ConstructorDoesntRequireConvertor(self):
     rvc = ResistanceValueConvertor(10, 10)
     rvc.convert(5)
 def test_ConvertorChainingWorksAsExpected(self):
     mock_vc = Mock()
     mock_vc.convert.return_value = 5
     rvc = ResistanceValueConvertor(10, 10, mock_vc)
     rvc.convert(5)
     mock_vc.convert.assert_called_once_with(5)