[SciPy-dev] Test Design Question for Stats.Models Code

[Robert Kern]

On Fri, Jul 17, 2009 at 12:18, Skipper Seabold<jsseabold@gmail.com> wrote:
> Hello all,
>
> I am polishing up the generalized linear models right now for the
> stats.models project and I have a question about using decorators with
> my tests.  The GLM framework has a central model with shared
> properties and then several variations on this model, so to test I
> have just as a simplified example:
>
> from numpy.testing import *
> DECIMAL = 4
> class check_glm(object):
>    '''
>    res2 results will be obtained from R or the RModelwrap
>    '''
>
>    def test_params(self):
>        assert_almost_equal(self.res1.params, self.res2.params, DECIMAL)
>
>    def test_resids(self):
>        assert_almost_equal(self.res1.resids, self.res2.resids, DECIMAL)
>
> class test_glm_gamma(check_glm):
>    def __init__(self):
> # Preprocessing to setup results
>        self.res1 = ResultsFromGLM
>        self.res2 = R_Results
>
> if __name__=="__main__":
>    run_module_suite()
>
> My question is whether I can skip, for arguments sake, test_resids
> depending, for example, on the class of self.res2 or because I defined
> the test condition as True in the test_<> class.   I tried putting in
> the check_glm class
>
> @dec.skipif(TestCondition, "Skipping this test because of ...")
> def test_resids(self):
> ...
>
> TestCondition should be None by default, but how can I get the value
> of TestCondition to evaluate to True if appropriate?  I have tried a
> few different ways, but I am a little stumped. Does this make sense/is
> it possible?  I'm sure I'm missing something obvious, but any insights
> would be appreciated.

I don't think you can do that with the decorator. Just do the test in
code inside the method and raise nose.SkipTest explicitly:

def test_resids(self):
    if not isinstance(self.res1, GLMResults):
        raise nose.SkipTest("Not a GLM test")

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco