import unittest

class AResult(unittest.TestResult):
    # this result class does something interesting with stream,
    # descriptions, and verbosity, so it requires them in its __init__
    # and presumably uses them in other methods.
    def __init__(self, stream, descriptions, verbosity):
        super(AResult, self).__init__(stream, descriptions, verbosity)
        self.stream = stream
        self.descriptions = descriptions
        self.verbosity = verbosity

class ATextResult(unittest.TextTestResult, AResult):
    # this result class descends--possibly through a more complex
    # inheritance chain--from both TextTestResult and AResult, adding some
    # of its own nifty code in the process. in particular, though, its
    # parent ordering puts TextTestResult earlier in the __mro__ than
    # AResult
    # NB: client code can work around this by swapping the parent order of
    # this class. that's pretty non-obvious, though, so it doesn't seem like
    # a good final answer to this problem.
    pass

class DummyTestCase(unittest.TestCase):
    # we need to run a test to demonstrate the problem. this one should pass.
    def testSanity(self):
        self.assertEqual(1, 1)

if __name__ == '__main__':
    # TextTestRunner or a descendent does something spiffy in our app but
    # needs ATextResult result objects to do it.
    runner = unittest.TextTestRunner(resultclass=ATextResult)
    # when we run the tests, creating the results object calls
    # TextTestResult.__init__(...). that method calls super(TextTestResult,
    # self).__init__() [no args], presumably assuming its parent is
    # TestResult. unfortunately, it's in ATextResult's __mro__ chain, which
    # puts AResult *after* TextTestResult. TextTestResult.__init__(...) thus
    # calls AResult.__init__(), which is invalid. it explodes because of the
    # incorrect call in TextTestResult.__init__(...), which should pass on
    # its own args instead of calling its super with no args.
    unittest.main(testRunner=runner)