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)