def test_input_transformed_single_series(self):
        """
        Tests for correct (inverse) transformation of single series.
        """
        test_input = constant_timeseries(value=1, length=10)

        mock = self.DataTransformerMock(scale=2, translation=10)

        transformed = mock.fit_transform(test_input)

        # 2 * 1 + 10 = 12
        expected = constant_timeseries(value=12, length=10)
        assert transformed == expected

        # Should get input back:
        assert mock.inverse_transform(transformed) == test_input

        Tests for correct (inverse) transformation of single series.
        
darts/tests/dataprocessing/transformers/test_invertible_fittable_data_transformer.py