manager.requestDurableHandle("/test/file.txt", HandleType.DURABLE_V2, 100, // 100ms timeout
                null);

        // Wait for expiration
        try {
            Thread.sleep(150);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }

        HandleInfo info = manager.getHandleForReconnect("/test/file.txt");
        assertNull(info);

        new Callable<@Nullable Void>() {
          @Override
          public @Nullable Void call() throws Exception {
            // adds two nanoseconds to the ticker
            ticker.advance(1L);
            Thread.sleep(10);
            ticker.advance(1L);
            return null;
          }
        });

    assertEquals(numberOfThreads * 2, ticker.read());
  }

  @GwtIncompatible // concurrency

        // Make the cache entry expired
        DirectoryCacheEntry entry = directoryLeaseManager.getCacheEntry(directoryPath);
        entry.setMaxAge(1); // 1ms to expire immediately
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            // Ignore
        }

        // When lease is lost, cache entry should be removed
        when(baseLeaseManager.getLease(leaseKey)).thenReturn(null);

        FtpClient client = new FtpClient() {
            @Override
            protected ResponseData getResponseData(final String uri, final boolean includeContent) {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    throw new CrawlingAccessException(e);
                }
                return null;
            }
        };

        IOException error = new IOException("Connection failed");
        failover.handleFailure(failedChannel, error);

        // Wait a bit for recovery attempt
        Thread.sleep(100);

        verify(mockChannelManager).createTransport(failedChannel.getLocalInterface(), failedChannel.getRemoteInterface());
    }

    @Test
    void testMultipleFailuresExceedRetryLimit() {

            @Override
            public void run() {
                try {
                    statusSetLatch.countDown();
                    // Poll for status change instead of fixed sleep
                    long startTime = System.currentTimeMillis();
                    while (System.currentTimeMillis() - startTime < 500) {
                        if (CrawlerStatus.DONE == crawlerContext.getStatus()) {

                    crawlerStatusList.set(startedCrawlerNum, Constants.RUNNING);
                    startedCrawlerNum++;
                    activeCrawlerNum++;
                    ThreadUtil.sleep(crawlingExecutionInterval);
                    continue;
                }

                // check status
                for (int i = 0; i < startedCrawlerNum; i++) {

    while (!isThreadBlockedOnInstanceOf(t, blocker)) {
      if (t.getState() == Thread.State.TERMINATED) {
        throw new RuntimeException("Thread " + t + " exited unexpectedly");
      }
      Thread.sleep(1);
    }
  }

  private static boolean isThreadBlockedOnInstanceOf(Thread t, Class<?> blocker) {
    return t.getState() == Thread.State.WAITING && blocker.isInstance(LockSupport.getBlocker(t));
  }

}

@AfterClass
public static void afterClass() {
    runner.close();
    runner.clean();
}
```

### Testing Best Practices

- Minimize `Thread.sleep()` - use only when absolutely necessary
- For timestamp tests: use minimal delays (50-100ms)
- Clean only test-specific indices (not `_all` unless needed)
- Use `runner.refresh()` after index operations

            try {
                // Wait before retry (except first attempt)
                if (attempt > 0) {
                    long delay = retryDelay * (1L << attempt); // Exponential backoff
                    Thread.sleep(delay);
                    log.debug("Reconnection attempt {} for {}", attempt + 1, info.getPath());
                }

                // Perform the actual reconnection