'A single wrong assertFailure should fail the whole test.'

def test_assertFailure_masked(self):

    class ExampleFailure(Exception, ):
        pass
    class TC(unittest.TestCase, ):
        failureException = ExampleFailure
        def test_assertFailure(self):
            d = defer.maybeDeferred((lambda : (1 / 0)))
            self.assertFailure(d, OverflowError)
            self.assertFailure(d, ZeroDivisionError)
            return d
    test = TC('test_assertFailure')
    result = pyunit.TestResult()
    test.run(result)
    self.assertEqual(1, len(result.failures))
