// First initialization
        if (client.isInit.compareAndSet(false, true)) {
            client.init();
        }
        assertTrue("Client should be initialized", client.isInit.get());

        // Second initialization attempt should be no-op
        boolean secondInit = client.isInit.compareAndSet(false, true);
        assertFalse("Second initialization should not occur", secondInit);

   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an
   * AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is

                if (logger.isDebugEnabled()) {
                    logger.debug("Process {} is not alive.", p);
                }
                return;
            }

            if (executed.compareAndSet(false, true)) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Interrupting a stream thread.");
                }
                ist.interrupt();

  }

  /**
   * Simulate some of the races that can happen on add. We can't easily simulate the race that
   * happens when an {@link AtomicInteger#compareAndSet} fails, but we can simulate the case where
   * the putIfAbsent returns a non-null value, and the case where the replace() of an observed zero
   * fails.
   */
  public void testAdd_withFailures() {

     * @return the response data
     * @throws CrawlingAccessException if the request fails
     */
    protected ResponseData processRequest(final String uri, final boolean includeContent) {
        if (isInit.compareAndSet(false, true)) {
            init();
        }

        // start
        AccessTimeoutTarget accessTimeoutTarget = null;
        TimeoutTask accessTimeoutTask = null;
        if (accessTimeout != null) {

   * test case failure. Only the first failure is recorded; subsequent calls to this method from
   * within the same test have no effect.
   */
  public void threadRecordFailure(Throwable t) {
    threadFailure.compareAndSet(null, t);
  }

  @Override
  public void setUp() {
    setDelays();
  }

  /**
   * Extra checks that get done for all test cases.
   *