assertTrue("Expected minimal sleep time with negative interval, got " + elapsed + "ms", elapsed < 50);
    }

    public void test_update_callsLoad() throws InterruptedException {
        CountDownLatch latch = new CountDownLatch(1);
        configHelper.setLoadCallback(() -> {
            latch.countDown();
            return 1;
        });

        configHelper.update();

 * period or an interrupt while waiting for the expected event will result in a {@link
 * RuntimeException}.
 *
 * <p>Here's an example that tests a {@code finalize} method:
 *
 * {@snippet :
 * final CountDownLatch latch = new CountDownLatch(1);
 * Object x = new MyClass() {
 *   ...
 *   protected void finalize() { latch.countDown(); ... }
 * };
 * x = null;  // Hint to the JIT that x is stack-unreachable
 * GcFinalization.await(latch);

            .build(computingFunction);

    // seed the map, so its segment's count > 0
    cache.getUnchecked("a");
    shouldWait.set(true);

    CountDownLatch computationStarted = new CountDownLatch(1);
    CountDownLatch computationComplete = new CountDownLatch(1);
    new Thread(
            new Runnable() {
              @Override
              public void run() {
                computationStarted.countDown();

            .build(computingFunction);

    // seed the map, so its segment's count > 0
    cache.getUnchecked("a");
    shouldWait.set(true);

    CountDownLatch computationStarted = new CountDownLatch(1);
    CountDownLatch computationComplete = new CountDownLatch(1);
    new Thread(
            new Runnable() {
              @Override
              public void run() {
                computationStarted.countDown();

      delayNanos,
    )
  }

  /** Returns a latch that reaches 0 when the queue is next idle. */
  fun idleLatch(): CountDownLatch {
    taskRunner.withLock {
      // If the queue is already idle, that's easy.
      if (activeTask == null && futureTasks.isEmpty()) {
        return CountDownLatch(0)
      }

      // If there's an existing AwaitIdleTask, use it. This is necessary when the executor is

  // Signals that the function is waiting to complete
  private CountDownLatch funcIsWaitingLatch;
  // Signals the function so it will complete
  private CountDownLatch funcCompletionLatch;

  @Override
  protected ListenableFuture<String> buildChainingFuture(ListenableFuture<Integer> inputFuture) {
    outputFuture = SettableFuture.create();
    funcIsWaitingLatch = new CountDownLatch(1);
    funcCompletionLatch = new CountDownLatch(1);

  // Signals that the function is waiting to complete
  private CountDownLatch funcIsWaitingLatch;
  // Signals the function so it will complete
  private CountDownLatch funcCompletionLatch;

  @Override
  protected ListenableFuture<String> buildChainingFuture(ListenableFuture<Integer> inputFuture) {
    outputFuture = SettableFuture.create();
    funcIsWaitingLatch = new CountDownLatch(1);
    funcCompletionLatch = new CountDownLatch(1);

  }

  private static class BlockingCallable implements Callable<@Nullable Void> {
    private final CountDownLatch startLatch = new CountDownLatch(1);
    private final CountDownLatch stopLatch = new CountDownLatch(1);

    private volatile boolean running = false;

    @Override
    public @Nullable Void call() throws InterruptedException {
      running = true;

            )
        .inOrder();
  }

  public void testLegacyAsyncDispatcher() {
    dispatcher = Dispatcher.legacyAsync();

    CyclicBarrier barrier = new CyclicBarrier(2);
    CountDownLatch latch = new CountDownLatch(2);

    new Thread(
            new Runnable() {
              @Override
              public void run() {
                try {
                  barrier.await();

      throws Exception {
    ExecutorService executorService = newFixedThreadPool(numberOfThreads);
    CountDownLatch startLatch = new CountDownLatch(numberOfThreads);
    CountDownLatch doneLatch = new CountDownLatch(numberOfThreads);
    for (int i = numberOfThreads; i > 0; i--) {
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored