def METHOD_NAME(self):
    ts = Touchstone("./tests/data/valid.s2p")
    self.assertEqual(ts.saves(), "# HZ S RI R 50\n")
    ts.load()
    lines = ts.saves().splitlines()
    self.assertEqual(len(lines), 1021)
    self.assertEqual(lines[0], "# HZ S RI R 50")
    self.assertEqual(lines[1], '500000 -0.333238 0.000180018')
    self.assertEqual(lines[-1], '900000000 -0.127646 0.31969')
    lines = ts.saves(4).splitlines()
    self.assertEqual(len(lines), 1021)
    self.assertEqual(lines[0], "# HZ S RI R 50")
    self.assertEqual(lines[1],
                     '500000 -0.333238 0.000180018 0.67478 -8.1951e-07'
                     ' 0.67529 -8.20129e-07 -0.333238 0.000308078')
    self.assertEqual(lines[-1],
                     '900000000 -0.127646 0.31969 0.596287 -0.503453'
                     ' 0.599076 -0.50197 -0.122713 0.326965')
    ts.filename = "./tests/data/output.s2p"
    ts.save(4)
    os.remove(ts.filename)
    ts.filename = ""
    self.assertRaises(FileNotFoundError, ts.save)
    ts.s11[0] = Datapoint(100, 0.1, 0.1)
    self.assertRaisesRegex(
        LookupError, "Frequencies of sdata not correlated", ts.saves, 4)