'When canceling a L{Deferred} from a L{DeferredLock} that does not
yet have the lock (i.e., the L{Deferred} has not fired), the cancel
should cause a L{defer.CancelledError} failure.'

def test_cancelLockBeforeAcquired(self):

    lock = defer.DeferredLock()
    lock.acquire()
    d = lock.acquire()
    d.cancel()
    self.assertImmediateFailure(d, defer.CancelledError)
