def METHOD_NAME(self):
    x = np.linspace(start=0.1, stop=10, num=10)
    y = np.linspace(start=0.1, stop=10, num=10)
    # test round case against TNFW
    kwargs_tnfw_e_round = {
        "Rs": 1,
        "alpha_Rs": 0.1,
        "r_trunc": 5,
        "e1": 0.0,
        "e2": 0,
    }
    kwargs_tnfw_round = {"Rs": 1, "alpha_Rs": 0.1, "r_trunc": 5}
    f_xe, f_ye = self.tnfw_e.derivatives(x, y, **kwargs_tnfw_e_round)
    f_xr, f_yr = self.tnfw.derivatives(x, y, **kwargs_tnfw_round)
    npt.assert_almost_equal(f_xe, f_xr, decimal=5)
    npt.assert_almost_equal(f_ye, f_yr, decimal=5)
    # test elliptical case with r_trunc -> infinity against NFW_ELLIPSE
    kwargs_tnfw_e = {
        "Rs": 1,
        "alpha_Rs": 0.1,
        "r_trunc": 500,
        "e1": 0.2,
        "e2": -0.01,
    }
    kwargs_nfw_e = {"Rs": 1, "alpha_Rs": 0.1, "e1": 0.2, "e2": -0.01}
    out_te = self.tnfw_e.derivatives(x, y, **kwargs_tnfw_e)
    out_e = self.nfw_e.derivatives(x, y, **kwargs_nfw_e)
    npt.assert_almost_equal(out_te, out_e, decimal=3)