q.take();
  }

  public void testDrain_throws() throws Exception {
    for (BlockingQueue<Object> q : blockingQueues()) {
      checkDrainThrows(q);
    }
  }

  private void checkDrainThrows(BlockingQueue<Object> q) {
    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored