'When passed a L{Deferred} which currently has a L{Failure} result
(ie, L{Deferred.addErrback} would cause the added errback to be called
before C{addErrback} returns), L{SynchronousTestCase.failureResultOf}
returns that L{Failure}.'

def test_withFailureResult(self):

    self.assertIdentical(self.failure, self.failureResultOf(fail(self.failure)))
