// Free the producer thread, and give subsequent tests a clean slate.
    q.take();
  }

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

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