def METHOD_NAME(self, gammacat, ref):
    source = gammacat[ref["name"]]
    spectral_model = source.spectral_model()
    e_min, e_max, e_inf = [1, 10, 1e10] * u.TeV
    dnde, dnde_err = spectral_model.evaluate_error(e_min)
    assert_quantity_allclose(dnde, ref["dnde_1TeV"], rtol=1e-3)
    assert_quantity_allclose(dnde_err, ref["dnde_1TeV_err"], rtol=1e-3)