def METHOD_NAME(self):
    y = np.array([1.0, 2])
    x = np.array([0.0, 0.0])
    mu_r = 1.0
    mu_t = 10.0
    # positive parity
    parity = 1
    ############
    # rotation 1
    ############
    phi_G = np.pi
    values = self.const_mag.function(x, y, mu_r, mu_t, parity, phi_G)
    delta_pot = values[1] - values[0]
    # rotate
    x__, y__ = util.rotate(x, y, phi_G)
    # evaluate
    f_ = self.const_mag.function(x__, y__, mu_r, mu_t, parity, 0.0)
    # rotate back
    delta_pot_rot = f_[1] - f_[0]
    # compare
    npt.assert_almost_equal(delta_pot, delta_pot_rot, decimal=4)
    ############
    # rotation 2
    ############
    phi_G = np.pi / 3.0
    values = self.const_mag.function(x, y, mu_r, mu_t, parity, phi_G)
    delta_pot = values[1] - values[0]
    # rotate
    x__, y__ = util.rotate(x, y, phi_G)
    # evaluate
    f_ = self.const_mag.function(x__, y__, mu_r, mu_t, parity, 0.0)
    # rotate back
    delta_pot_rot = f_[1] - f_[0]
    # compare
    npt.assert_almost_equal(delta_pot, delta_pot_rot, decimal=4)
    # ===========================================================
    # negative parity
    parity = -1
    ############
    # rotation 1
    ############
    phi_G = np.pi
    values = self.const_mag.function(x, y, mu_r, mu_t, parity, phi_G)
    delta_pot = values[1] - values[0]
    # rotate
    x__, y__ = util.rotate(x, y, phi_G)
    # evaluate
    f_ = self.const_mag.function(x__, y__, mu_r, mu_t, parity, 0.0)
    # rotate back
    delta_pot_rot = f_[1] - f_[0]
    # compare
    npt.assert_almost_equal(delta_pot, delta_pot_rot, decimal=4)
    ############
    # rotation 2
    ############
    phi_G = np.pi / 3.0
    values = self.const_mag.function(x, y, mu_r, mu_t, parity, phi_G)
    delta_pot = values[1] - values[0]
    # rotate
    x__, y__ = util.rotate(x, y, phi_G)
    # evaluate
    f_ = self.const_mag.function(x__, y__, mu_r, mu_t, parity, 0.0)
    # rotate back
    delta_pot_rot = f_[1] - f_[0]
    # compare
    npt.assert_almost_equal(delta_pot, delta_pot_rot, decimal=4)