message: add useless tests
diff: @@ -209,9 +209,7 @@ impl<T> SpinlockIrqSave<T> {
  impl<T: ?Sized> SpinlockIrqSave<T> {
  fn obtain_lock(&self) {
  - #[cfg(not(test))]
  let irq = irq::nested_disable();
  - #[cfg(test)]
  let irq = false;
  let ticket = self.queue.fetch_add(1, Ordering::SeqCst) + 1;
  @@ -265,7 +263,6 @@ impl<'a, T: ?Sized> Drop for SpinlockIrqSaveGuard<'a, T> {
  fn drop(&mut self) {
  let irq = self.irq.swap(false, Ordering::SeqCst);
  self.dequeue.fetch_add(1, Ordering::SeqCst);
  - #[cfg(not(test))]
  irq::nested_enable(irq);
  }
  }
  @@ -316,39 +313,4 @@ mod tests {
  }
  assert_eq!(*S.lock(), J * K * 2);
  }
  -
  - #[test]
  - fn lock_test2() {
  - static S: SpinlockIrqSave<u32> = SpinlockIrqSave::new(0);
  - const J: u32 = 500;
  - const K: u32 = 3;
  -
  - fn inc() {
  - for _ in 0..J {
  - unsafe {
  - *S.lock() += 1;
  - }
  - }
  - }
  -
  - let (tx, rx) = channel();
  - for _ in 0..K {
  - let tx2 = tx.clone();
  - thread::spawn(move || {
  - inc();
  - tx2.send(()).unwrap();
  - });
  - let tx2 = tx.clone();
  - thread::spawn(move || {
  - inc();
  - tx2.send(()).unwrap();
  - });
  - }
  -
  - drop(tx);
  - for _ in 0..2 * K {
  - rx.recv().unwrap();
  - }
  - assert_eq!(*S.lock(), J * K * 2);
  - }
  }
  