'Tests Poisson family with canonical log link.
Test results were obtained by R.'

@classmethod
def setup_class(cls):

    from .results.results_glm import Cpunish
    from statsmodels.datasets.cpunish import load
    cls.data = load()
    cls.data.exog[:, 3] = np.log(cls.data.exog[:, 3])
    cls.data.exog = add_constant(cls.data.exog, prepend=False)
    cls.res1 = GLM(cls.data.endog, cls.data.exog, family=sm.families.Poisson()).fit()
    cls.res2 = Cpunish()
    modd = discrete.Poisson(cls.data.endog, cls.data.exog)
    cls.resd = modd.fit(start_params=(cls.res1.params * 0.9), disp=False)
