'A L{Deferred} without a canceller, when cancelled and then
callbacked, ignores multiple cancels thereafter.'

def test_noCancellerMultipleCancelsAfterCancelAndCallback(self):

    d = defer.Deferred()
    d.addCallbacks(self._callback, self._errback)
    d.cancel()
    currentFailure = self.errbackResults
    d.callback(None)
    d.cancel()
    self.assertIs(currentFailure, self.errbackResults)
