'Tests the Inverse Gaussian family in GLM.
Notes
Used the rndivgx.ado file provided by Hardin and Hilbe to
generate the data.  Results are read from model_results, which
were obtained by running R_ig.s'

@classmethod
def setup_class(cls):

    cls.decimal_aic_R = DECIMAL_0
    cls.decimal_loglike = DECIMAL_0
    from .results.results_glm import InvGauss
    res2 = InvGauss()
    res1 = GLM(res2.endog, res2.exog, family=sm.families.InverseGaussian()).fit()
    cls.res1 = res1
    cls.res2 = res2
