"""
unit test for GAM

Author: Josef Perktold

"""

import os

import numpy as np
from numpy.testing import assert_, assert_allclose, assert_equal
import pandas as pd
import patsy
import pytest

from statsmodels.base._penalized import PenalizedMixin
import statsmodels.base._penalties as smpen
from statsmodels.discrete.discrete_model import Logit, Poisson, Probit
from statsmodels.gam.generalized_additive_model import (
    GLMGam,
    GLMGamResults,
    GLMGamResultsWrapper,
)
from statsmodels.gam.smooth_basis import BSplines, CyclicCubicSplines
from statsmodels.genmod.families import family
from statsmodels.genmod.generalized_linear_model import GLM
from statsmodels.sandbox.regression.penalized import TheilGLS
from statsmodels.tools.linalg import matrix_sqrt, transf_constraints

from .results import results_mpg_bs, results_mpg_bs_poisson, results_pls


class PoissonPenalized(PenalizedMixin, Poisson):
    pass


class LogitPenalized(PenalizedMixin, Logit):
    pass


class ProbitPenalized(PenalizedMixin, Probit):
    pass


class GLMPenalized(PenalizedMixin, GLM):
    pass


cur_dir = os.path.dirname(os.path.abspath(__file__))

file_path = os.path.join(cur_dir, "results", "motorcycle.csv")
data_mcycle = pd.read_csv(file_path)

file_path = os.path.join(cur_dir, "results", "autos.csv")
df_autos_ = pd.read_csv(file_path)
df_autos = df_autos_[["city_mpg", "fuel", "drive", "weight", "hp"]].dropna()


class CheckGAMMixin:

    @classmethod
    def _init(cls):
        # TODO: CyclicCubicSplines raises when using pandas
        cc_h = CyclicCubicSplines(np.asarray(data_mcycle["times"]), df=[6])

        constraints = np.atleast_2d(cc_h.basis.mean(0))
        transf = transf_constraints(constraints)

        exog = cc_h.basis.dot(transf)
        penalty_matrix = transf.T.dot(cc_h.penalty_matrices[0]).dot(transf)
        restriction = matrix_sqrt(penalty_matrix)
        return exog, penalty_matrix, restriction

    def test_params(self):
        res1 = self.res1
        res2 = self.res2
        assert_allclose(res1.params, res2.params, rtol=1e-5)
        assert_allclose(
            np.asarray(res1.cov_params()),
            res2.Vp * self.covp_corrfact,
            rtol=1e-6,
            atol=1e-9,
        )

        assert_allclose(res1.scale, res2.scale * self.covp_corrfact, rtol=1e-8)

        assert_allclose(
            np.asarray(res1.bse),
            res2.se * np.sqrt(self.covp_corrfact),
            rtol=1e-6,
            atol=1e-9,
        )

    def test_fitted(self):
        res1 = self.res1
        res2 = self.res2
        assert_allclose(res1.fittedvalues, res2.fitted_values, rtol=self.rtol_fitted)

    @pytest.mark.smoke
    def test_null_smoke(self):
        self.res1.llnull


class TestTheilPLS5(CheckGAMMixin):

    cov_type = "data-prior"

    @classmethod
    def setup_class(cls):
        exog, penalty_matrix, restriction = cls._init()
        endog = data_mcycle["accel"]
        modp = TheilGLS(endog, exog, r_matrix=restriction)
        # scaling of penweith in R mgcv
        s_scale_r = 0.02630734
        # Theil penweight uses preliminary sigma2_e to scale penweight
        sigma_e = 1405.7950179165323
        cls.pw = pw = 1 / sigma_e / s_scale_r
        cls.res1 = modp.fit(pen_weight=pw, cov_type=cls.cov_type)
        cls.res2 = results_pls.pls5

        cls.rtol_fitted = 1e-7
        cls.covp_corrfact = 0.99786932844203202

    def test_cov_robust(self):
        res1 = self.res1
        res2 = self.res2
        pw = res1.penalization_factor
        res1 = res1.model.fit(pen_weight=pw, cov_type="sandwich")
        assert_allclose(
            np.asarray(res1.cov_params()), res2.Ve * self.covp_corrfact, rtol=1e-4
        )

    def test_null_smoke(self):
        pytest.skip("llnull not available")


class TestGLMPenalizedPLS5(CheckGAMMixin):

    cov_type = "nonrobust"

    @classmethod
    def setup_class(cls):
        exog, penalty_matrix, restriction = cls._init()
        endog = data_mcycle["accel"]
        pen = smpen.L2ConstraintsPenalty(restriction=restriction)
        mod = GLMPenalized(endog, exog, family=family.Gaussian(), penal=pen)
        # scaling of penweight in R mgcv
        s_scale_r = 0.02630734
        # set pen_weight to correspond to R mgcv example
        cls.pw = mod.pen_weight = 1 / s_scale_r / 2
        cls.res1 = mod.fit(
            cov_type=cls.cov_type,
            method="bfgs",
            maxiter=100,
            disp=0,
            trim=False,
            scale="x2",
        )
        cls.res2 = results_pls.pls5

        cls.rtol_fitted = 1e-5
        # edf is currently not available with PenalizedMixin
        # need correction for difference in scale denominator
        cls.covp_corrfact = 1.0025464444310588

    def _test_cov_robust(self):
        # TODO: HC0 differs from Theil sandwich, difference is large
        res1 = self.res1
        res2 = self.res2
        pw = res1.model.pen_weight
        res1 = res1.model.fit(pen_weight=pw, cov_type="HC0")
        assert_allclose(
            np.asarray(res1.cov_params()), res2.Ve * self.covp_corrfact, rtol=1e-4
        )


class TestGAM5Pirls(CheckGAMMixin):

    cov_type = "nonrobust"

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214

        x = data_mcycle["times"].values
        endog = data_mcycle["accel"]
        cc = CyclicCubicSplines(x, df=[6], constraints="center")
        gam_cc = GLMGam(endog, smoother=cc, alpha=1 / s_scale / 2)
        cls.res1 = gam_cc.fit()
        cls.res2 = results_pls.pls5

        cls.rtol_fitted = 1e-12
        # cls.covp_corrfact = 1.0025464444310588  # without edf
        # edf is implemented
        cls.covp_corrfact = 1


class TestGAM5Bfgs(CheckGAMMixin):

    cov_type = "nonrobust"

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214

        x = data_mcycle["times"].values
        endog = data_mcycle["accel"]
        cc = CyclicCubicSplines(x, df=[6], constraints="center")
        gam_cc = GLMGam(endog, smoother=cc, alpha=1 / s_scale / 2)
        cls.res1 = gam_cc.fit(method="bfgs")
        cls.res2 = results_pls.pls5

        cls.rtol_fitted = 1e-5
        # cls.covp_corrfact = 1.0025464444310588  # without edf
        # edf is implemented
        cls.covp_corrfact = 1

    def test_predict(self):
        res1 = self.res1
        res2 = self.res2
        predicted = res1.predict(None, res1.model.smoother.x[2:4])
        assert_allclose(predicted, res1.fittedvalues[2:4], rtol=1e-13)
        assert_allclose(predicted, res2.fitted_values[2:4], rtol=self.rtol_fitted)


class TestGAM6Pirls:

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214

        cc = CyclicCubicSplines(data_mcycle["times"].values, df=[6])
        gam_cc = GLMGam(data_mcycle["accel"], smoother=cc, alpha=1 / s_scale / 2)
        cls.res1 = gam_cc.fit()

    def test_fitted(self):
        res1 = self.res1
        pred = res1.get_prediction()
        self.rtol_fitted = 1e-7
        pls6_fittedvalues = np.array(
            [
                2.45008146537851,
                3.14145063965465,
                5.24130119353225,
                6.63476330674223,
                7.99704341866374,
                13.9351103077006,
                14.5508371638833,
                14.785647621276,
                15.1176070735895,
                14.8053514054347,
                13.790412967255,
                13.790412967255,
                11.2997845518655,
                9.51681958051473,
                8.4811626302547,
            ]
        )
        assert_allclose(
            res1.fittedvalues[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )
        assert_allclose(
            pred.predicted_mean[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )

        predicted = res1.predict(None, res1.model.smoother.x[2:4])
        assert_allclose(predicted, pls6_fittedvalues[2:4], rtol=self.rtol_fitted)


class TestGAM6Bfgs:

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214

        cc = CyclicCubicSplines(data_mcycle["times"].values, df=[6])
        gam_cc = GLMGam(data_mcycle["accel"], smoother=cc, alpha=1 / s_scale / 2)
        cls.res1 = gam_cc.fit(method="bfgs")

    def test_fitted(self):
        res1 = self.res1
        pred = res1.get_prediction()
        self.rtol_fitted = 1e-5
        pls6_fittedvalues = np.array(
            [
                2.45008146537851,
                3.14145063965465,
                5.24130119353225,
                6.63476330674223,
                7.99704341866374,
                13.9351103077006,
                14.5508371638833,
                14.785647621276,
                15.1176070735895,
                14.8053514054347,
                13.790412967255,
                13.790412967255,
                11.2997845518655,
                9.51681958051473,
                8.4811626302547,
            ]
        )
        assert_allclose(
            res1.fittedvalues[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )
        assert_allclose(
            pred.predicted_mean[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )


class TestGAM6Bfgs0:

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214  # noqa: F841

        cc = CyclicCubicSplines(data_mcycle["times"].values, df=[6])
        gam_cc = GLMGam(data_mcycle["accel"], smoother=cc, alpha=0)
        cls.res1 = gam_cc.fit(method="bfgs")

    def test_fitted(self):
        res1 = self.res1
        pred = res1.get_prediction()
        self.rtol_fitted = 1e-5
        pls6_fittedvalues = np.array(
            [
                2.63203377595747,
                3.41285892739456,
                5.78168657308338,
                7.35344779586831,
                8.89178704316853,
                15.7035642157176,
                16.4510219628328,
                16.7474993878412,
                17.3397025587698,
                17.1062522298643,
                16.1786066072489,
                16.1786066072489,
                13.7402485937614,
                11.9531909618517,
                10.9073964111009,
            ]
        )
        assert_allclose(
            res1.fittedvalues[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )
        assert_allclose(
            pred.predicted_mean[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )


pls6_fittedvalues = np.array(
    [
        2.45008146537851,
        3.14145063965465,
        5.24130119353225,
        6.63476330674223,
        7.99704341866374,
        13.9351103077006,
        14.5508371638833,
        14.785647621276,
        15.1176070735895,
        14.8053514054347,
        13.790412967255,
        13.790412967255,
        11.2997845518655,
        9.51681958051473,
        8.4811626302547,
    ]
)

pls6_exog = np.array(
    [
        1,
        1,
        1,
        1,
        1,
        1,
        1,
        1,
        1,
        1,
        -0.334312615555276,
        -0.302733562622373,
        -0.200049479196403,
        -0.12607681525989,
        -0.0487229716135211,
        0.397628373646056,
        0.475396222437879,
        0.51311526571058,
        0.685638355361239,
        0.745083051531164,
        -0.633518318499726,
        -0.634362488928233,
        -0.635472088268483,
        -0.634802453890957,
        -0.632796625534419,
        -0.589886140629009,
        -0.574834708734556,
        -0.566315983948608,
        -0.51289784236512,
        -0.486061743835595,
        -0.353449234316442,
        -0.348107090921062,
        -0.328814083307981,
        -0.313617048982477,
        -0.296913301955505,
        -0.191949693921079,
        -0.173001127145111,
        -0.163813487426548,
        -0.12229019995063,
        -0.108463798212062,
        -0.33613551740577,
        -0.327911471033406,
        -0.303620832999443,
        -0.287786799373968,
        -0.272279566127816,
        -0.194325957984873,
        -0.18175817334823,
        -0.175688807660186,
        -0.147654475500976,
        -0.137597948224942,
        -0.406564043706154,
        -0.409594429953082,
        -0.412391645561287,
        -0.409453786864986,
        -0.403086590828732,
        -0.322579243114146,
        -0.302545882788086,
        -0.29221622484174,
        -0.239207291311699,
        -0.218194346676734,
    ]
).reshape(10, 6, order="F")


class TestGAM6ExogBfgs:

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214
        nobs = data_mcycle["times"].shape[0]
        cc = CyclicCubicSplines(
            data_mcycle["times"].values, df=[6], constraints="center"
        )
        gam_cc = GLMGam(
            data_mcycle["accel"], np.ones(nobs), smoother=cc, alpha=1 / s_scale / 2
        )
        cls.res1 = gam_cc.fit(method="bfgs")

    def test_fitted(self):
        res1 = self.res1
        pred = res1.get_prediction()
        self.rtol_fitted = 1e-5

        assert_allclose(
            res1.fittedvalues[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )
        assert_allclose(
            pred.predicted_mean[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )

    def test_exog(self):
        exog = self.res1.model.exog
        assert_allclose(exog[:10], pls6_exog, rtol=1e-13)


class TestGAM6ExogPirls:

    @classmethod
    def setup_class(cls):
        s_scale = 0.0263073404164214
        nobs = data_mcycle["times"].shape[0]
        cc = CyclicCubicSplines(
            data_mcycle["times"].values, df=[6], constraints="center"
        )
        gam_cc = GLMGam(
            data_mcycle["accel"], np.ones((nobs, 1)), smoother=cc, alpha=1 / s_scale / 2
        )
        cls.res1 = gam_cc.fit(method="pirls")

    def test_fitted(self):
        res1 = self.res1
        pred = res1.get_prediction()
        self.rtol_fitted = 1e-5

        assert_allclose(
            res1.fittedvalues[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )
        assert_allclose(
            pred.predicted_mean[:15], pls6_fittedvalues, rtol=self.rtol_fitted
        )

    def test_exog(self):
        exog = self.res1.model.exog
        assert_allclose(exog[:10], pls6_exog, rtol=1e-13)


class TestGAMMPG:

    @classmethod
    def setup_class(cls):

        sp = np.array([6.46225497484073, 0.81532465890585])
        s_scale = np.array([2.95973613706629e-07, 0.000126203730141359])

        x_spline = df_autos[["weight", "hp"]].values
        exog = patsy.dmatrix("fuel + drive", data=df_autos)
        cc = CyclicCubicSplines(x_spline, df=[6, 5], constraints="center")
        # TODO alpha needs to be list
        gam_cc = GLMGam(
            df_autos["city_mpg"],
            exog=exog,
            smoother=cc,
            alpha=(1 / s_scale * sp / 2).tolist(),
        )
        cls.res1a = gam_cc.fit()
        gam_cc = GLMGam(
            df_autos["city_mpg"],
            exog=exog,
            smoother=cc,
            alpha=(1 / s_scale * sp / 2).tolist(),
        )
        cls.res1b = gam_cc.fit(method="newton")

    def test_exog(self):
        file_path = os.path.join(cur_dir, "results", "autos_exog.csv")
        df_exog = pd.read_csv(file_path)
        res2_exog = df_exog.values
        for res1 in [self.res1a, self.res1b]:
            exog = res1.model.exog
            # exog contains zeros
            assert_allclose(exog, res2_exog, atol=1e-14)

    def test_fitted(self):
        file_path = os.path.join(cur_dir, "results", "autos_predict.csv")
        df_pred = pd.read_csv(file_path, index_col="Row.names")
        df_pred.index = df_pred.index - 1
        res2_fittedvalues = df_pred["fit"].values
        res2_se_mean = df_pred["se_fit"].values
        for res1 in [self.res1a, self.res1b]:
            pred = res1.get_prediction()
            self.rtol_fitted = 1e-5

            assert_allclose(res1.fittedvalues, res2_fittedvalues, rtol=1e-10)
            assert_allclose(pred.predicted_mean, res2_fittedvalues, rtol=1e-10)

            # TODO: no edf, edf corrected df_resid
            # scale estimate differs
            # corr_fact = np.sqrt(191.669417019567 / 190)  # without edf
            # edf is implemented
            corr_fact = 1
            assert_allclose(pred.se_mean, res2_se_mean * corr_fact, rtol=1e-10)


class TestGAMMPGBS(CheckGAMMixin):
    # This has matching results from mgcv

    @classmethod
    def setup_class(cls):

        sp = np.array([0.830689464223685, 425.361212061649])
        cls.s_scale = s_scale = np.array([2.443955e-06, 0.007945455])

        x_spline = df_autos[["weight", "hp"]].values
        # We need asarray to remove the design_info
        # If design_info is attached,
        #     then exog_linear will also be transformed in predict.
        cls.exog = np.asarray(patsy.dmatrix("fuel + drive", data=df_autos))
        bs = BSplines(
            x_spline,
            df=[12, 10],
            degree=[3, 3],
            variable_names=["weight", "hp"],
            constraints="center",
            include_intercept=True,
        )
        # TODO alpha needs to be list
        alpha0 = 1 / s_scale * sp / 2
        gam_bs = GLMGam(
            df_autos["city_mpg"], exog=cls.exog, smoother=bs, alpha=(alpha0).tolist()
        )
        cls.res1a = gam_bs.fit(use_t=True)

        cls.res1b = gam_bs.fit(method="newton", use_t=True)
        cls.res1 = cls.res1a._results
        cls.res2 = results_mpg_bs.mpg_bs

        cls.rtol_fitted = 1e-8
        cls.covp_corrfact = 1  # not needed

        # for checking that alpha model attribute is unchanged, same as alpha0
        cls.alpha = [169947.78222669504, 26767.58046340008]

    @classmethod
    def _init(cls):
        pass

    def test_edf(self):
        res1 = self.res1
        res2 = self.res2
        assert_allclose(res1.edf, res2.edf_all, rtol=1e-6)
        hat = res1.get_hat_matrix_diag()
        assert_allclose(hat, res2.hat, rtol=1e-6)

    def test_smooth(self):
        res1 = self.res1
        res2 = self.res2
        smoothers = res1.model.smoother.smoothers
        pen_matrix0 = smoothers[0].cov_der2
        assert_allclose(pen_matrix0, res2.smooth0.S * res2.smooth0.S_scale, rtol=1e-6)

    def test_predict(self):
        res1 = self.res1
        res2 = self.res2
        predicted = res1.predict(self.exog[2:4], res1.model.smoother.x[2:4])
        assert_allclose(predicted, res1.fittedvalues[2:4], rtol=1e-13)
        assert_allclose(predicted, res2.fitted_values[2:4], rtol=self.rtol_fitted)

    def test_crossval(self):
        # includes some checks that penalization in the model is unchanged
        mod = self.res1.model
        assert_equal(mod.alpha, self.alpha)  # assert unchanged
        assert_allclose(self.res1.scale, 4.7064821354391118, rtol=1e-13)

        alpha_aic = mod.select_penweight()[0]
        # regression number, but in the right ball park
        assert_allclose(alpha_aic, [112487.81362014, 129.89155677], rtol=1e-3)
        assert_equal(mod.alpha, self.alpha)  # assert unchanged
        assert_equal(mod.penal.start_idx, 4)
        pm = mod.penal.penalty_matrix()
        assert_equal(pm[:, :4], 0)
        assert_equal(pm[:4, :], 0)
        assert_allclose(self.res1.scale, 4.7064821354391118, rtol=1e-13)

        np.random.seed(987125)
        alpha_cv, _ = mod.select_penweight_kfold(k_folds=3, k_grid=6)
        # regression number, but in the right ball park
        assert_allclose(alpha_cv, [10000000.0, 630.957344480193], rtol=1e-5)
        assert_equal(mod.alpha, self.alpha)  # assert unchanged
        assert_equal(mod.penal.start_idx, 4)
        pm = mod.penal.penalty_matrix()
        assert_equal(pm[:, :4], 0)
        assert_equal(pm[:4, :], 0)
        assert_allclose(self.res1.scale, 4.7064821354391118, rtol=1e-13)


class TestGAMMPGBSPoisson(CheckGAMMixin):
    # This has matching results from mgcv

    @classmethod
    def setup_class(cls):

        sp = np.array([40491.3940640059, 232455.530262537])
        # s_scale is same as before
        cls.s_scale = s_scale = np.array([2.443955e-06, 0.007945455])

        x_spline = df_autos[["weight", "hp"]].values
        cls.exog = patsy.dmatrix("fuel + drive", data=df_autos)
        bs = BSplines(
            x_spline,
            df=[12, 10],
            degree=[3, 3],
            variable_names=["weight", "hp"],
            constraints="center",
            include_intercept=True,
        )
        # TODO alpha needs to be list
        alpha0 = 1 / s_scale * sp / 2
        gam_bs = GLMGam(
            df_autos["city_mpg"],
            exog=cls.exog,
            smoother=bs,
            family=family.Poisson(),
            alpha=alpha0,
        )

        xnames = cls.exog.design_info.column_names + gam_bs.smoother.col_names
        gam_bs.exog_names[:] = xnames
        cls.res1a = gam_bs.fit(use_t=False)

        cls.res1b = gam_bs.fit(method="newton", use_t=True)
        cls.res1 = cls.res1a._results
        cls.res2 = results_mpg_bs_poisson.mpg_bs_poisson

        cls.rtol_fitted = 1e-8
        cls.covp_corrfact = 1  # not needed

    @classmethod
    def _init(cls):
        pass

    def test_edf(self):
        res1 = self.res1
        res2 = self.res2
        assert_allclose(res1.edf, res2.edf_all, rtol=1e-6)
        hat = res1.get_hat_matrix_diag()
        assert_allclose(hat, res2.hat, rtol=1e-6)
        assert_allclose(res1.aic, res2.aic, rtol=1e-8)
        assert_allclose(res1.deviance, res2.deviance, rtol=1e-8)
        assert_allclose(res1.df_resid, res2.residual_df, rtol=1e-8)

    def test_smooth(self):
        res1 = self.res1
        res2 = self.res2

        smoothers = res1.model.smoother.smoothers
        pen_matrix0 = smoothers[0].cov_der2
        assert_allclose(pen_matrix0, res2.smooth0.S * res2.smooth0.S_scale, rtol=1e-6)

    def test_predict(self):
        res1 = self.res1
        res2 = self.res2
        # this uses transform also for exog_linear
        # predicted = res1.predict(self.exog[2:4], res1.model.smoother.x[2:4])
        predicted = res1.predict(df_autos.iloc[2:4], res1.model.smoother.x[2:4])
        assert_allclose(predicted, res1.fittedvalues[2:4], rtol=1e-13)
        assert_allclose(predicted, res2.fitted_values[2:4], rtol=self.rtol_fitted)

        # linpred = res1.predict(self.exog[2:4], res1.model.smoother.x[2:4],
        #                        linear=True)
        xp = pd.DataFrame(res1.model.smoother.x[2:4])
        linpred = res1.predict(df_autos.iloc[2:4], xp, which="linear")
        assert_allclose(linpred, res2.linear_predictors[2:4], rtol=self.rtol_fitted)

        assert_equal(predicted.index.values, [2, 3])
        assert_equal(linpred.index.values, [2, 3])

    def test_wald(self):
        res1 = self.res1
        res2 = self.res2
        wtt = res1.wald_test_terms(
            skip_single=True,
            combine_terms=["fuel", "drive", "weight", "hp"],
            scalar=True,
        )
        # mgcv has term test for linear part
        assert_allclose(wtt.statistic[:2], res2.pTerms_chi_sq, rtol=1e-7)
        assert_allclose(wtt.pvalues[:2], res2.pTerms_pv, rtol=1e-6)
        assert_equal(wtt.df_constraints[:2], res2.pTerms_df)

    def test_select_alpha(self):
        res1 = self.res1
        alpha_mgcv = res1.model.alpha
        res_s = res1.model.select_penweight()
        assert_allclose(res_s[0], alpha_mgcv, rtol=5e-5)


class TestGAMMPGBSPoissonFormula(TestGAMMPGBSPoisson):
    # This is the same as the previous but with from_formula

    @classmethod
    def setup_class(cls):

        sp = np.array([40491.3940640059, 232455.530262537])
        # s_scale is same as before
        cls.s_scale = s_scale = np.array([2.443955e-06, 0.007945455])

        cls.exog = patsy.dmatrix("fuel + drive", data=df_autos)

        x_spline = df_autos[["weight", "hp"]].values
        bs = BSplines(
            x_spline,
            df=[12, 10],
            degree=[3, 3],
            variable_names=["weight", "hp"],
            constraints="center",
            include_intercept=True,
        )

        alpha0 = 1 / s_scale * sp / 2
        gam_bs = GLMGam.from_formula(
            "city_mpg ~ fuel + drive",
            df_autos,
            smoother=bs,
            family=family.Poisson(),
            alpha=alpha0,
        )

        cls.res1a = gam_bs.fit(use_t=False)

        cls.res1b = gam_bs.fit(method="newton", use_t=True)
        cls.res1 = cls.res1a._results
        cls.res2 = results_mpg_bs_poisson.mpg_bs_poisson

        cls.rtol_fitted = 1e-8
        cls.covp_corrfact = 1  # not needed

    def test_names_wrapper(self):
        res1a = self.res1a
        xnames = [
            "Intercept",
            "fuel[T.gas]",
            "drive[T.fwd]",
            "drive[T.rwd]",
            "weight_s0",
            "weight_s1",
            "weight_s2",
            "weight_s3",
            "weight_s4",
            "weight_s5",
            "weight_s6",
            "weight_s7",
            "weight_s8",
            "weight_s9",
            "weight_s10",
            "hp_s0",
            "hp_s1",
            "hp_s2",
            "hp_s3",
            "hp_s4",
            "hp_s5",
            "hp_s6",
            "hp_s7",
            "hp_s8",
        ]

        assert_equal(res1a.model.exog_names, xnames)
        assert_equal(res1a.model.design_info_linear.column_names, xnames[:4])

        assert_equal(res1a.fittedvalues.iloc[2:4].index.values, [2, 3])
        assert list(res1a.params.index) == xnames
        assert_(isinstance(res1a.params, pd.Series))

        assert_(isinstance(res1a, GLMGamResultsWrapper))
        assert_(isinstance(res1a._results, GLMGamResults))