def METHOD_NAME(self):
    linphase = LinearPhaseFunc(5 * u.mag, 0.04 * u.mag/u.deg,
                               radius=300 * u.km, wfb='V')
    pha_test = np.linspace(0, 180, 10) * u.deg
    eph = linphase.to_ref(pha_test, append_results=True)
    ref_test = [1.55045242e-02, 7.42093183e-03, 3.55188129e-03,
                1.70003727e-03, 8.13688994e-04, 3.89456039e-04,
                1.86405380e-04, 8.92192241e-05, 4.27030055e-05,
                2.04389434e-05] / u.sr
    ref_norm_test = np.array(
        [1., 0.47863009, 0.22908677, 0.10964782, 0.05248075,
         0.02511886, 0.01202264, 0.0057544, 0.00275423,
         0.00131826]) * u.dimensionless_unscaled
    assert u.allclose(eph['ref'], ref_test)
    assert u.allclose(eph['alpha'], pha_test)
    assert set(eph.field_names) == {'alpha', 'ref'}
    eph_norm = linphase.to_ref(pha_test, normalized=0 * u.deg,
                               append_results=True)
    assert u.allclose(eph_norm['ref'], ref_norm_test)
    assert u.allclose(eph_norm['alpha'], pha_test)
    assert set(eph_norm.field_names) == {'alpha', 'ref'}
    eph = linphase.to_ref(eph, append_results=True)
    assert set(eph.field_names) == {'alpha', 'ref', 'ref1'}
    # test exception
    linphase = LinearPhaseFunc(5 * u.mag, 0.04 * u.mag/u.deg,
                               radius=300 * u.km)
    with pytest.raises(ValueError):
        linphase.to_ref(10 * u.deg)