def METHOD_NAME(ph_zr3n4: Phonopy):
    """Test displacements of Zr3N4."""
    dataset = deepcopy(ph_zr3n4.dataset)
    disp_ref = [
        [0, 0.01, 0.0, 0.0],
        [0, -0.01, 0.0, 0.0],
        [16, 0.01, 0.0, 0.0],
        [16, 0.0, 0.01, 0.0],
    ]
    np.testing.assert_allclose(ph_zr3n4.displacements, disp_ref, atol=1e-8)
    ph_zr3n4.generate_displacements()
    disp_gen = [
        [0, 0.01, 0.0, 0.0],
        [0, -0.01, 0.0, 0.0],
        [16, 0.007071067811865475, 0.007071067811865475, 0.0],
        [16, -0.007071067811865475, -0.007071067811865475, 0.0],
    ]
    np.testing.assert_allclose(ph_zr3n4.displacements, disp_gen, atol=1e-8)
    ph_zr3n4.dataset = dataset