def matrix_type(request):
    return request.param
def test_contains_itself(self):
        class Recursive(Structure):
            pass

        try:
            Recursive._fields_ = [("next", Recursive)]
        except AttributeError as details:
            self.assertTrue("Structure or union cannot contain itself" in
                            str(details))
        else:
            self.fail("Structure or union cannot contain itself")