def METHOD_NAME(self):
    """Test :func:`colour.models.igpgtg.IgPgTg_to_XYZ` definition."""
    np.testing.assert_array_almost_equal(
        IgPgTg_to_XYZ(np.array([0.42421258, 0.18632491, 0.10689223])),
        np.array([0.20654008, 0.12197225, 0.05136952]),
        decimal=7,
    )
    np.testing.assert_array_almost_equal(
        IgPgTg_to_XYZ(np.array([0.50912820, -0.14804331, 0.11921472])),
        np.array([0.14222010, 0.23042768, 0.10495772]),
        decimal=7,
    )
    np.testing.assert_array_almost_equal(
        IgPgTg_to_XYZ(np.array([0.29095152, -0.04057508, -0.18220795])),
        np.array([0.07818780, 0.06157201, 0.28099326]),
        decimal=7,
    )