def METHOD_NAME(self):
    """Test the linear transfomer."""
    df = self.df
    tmr = LinearTransform()
    for input in [df, df.values]:
        with self.subTest(input=input):
            out = tmr.transform(input)
            inv = tmr.inverse_transform(out)
            self.assertTrue(np.allclose(np.array(inv), np.array(input)))