int expectedOccupiedDepth) {
    AtomicBoolean actualIsOccupied = new AtomicBoolean();
    AtomicBoolean actualIsOccupiedByCurrentThread = new AtomicBoolean();
    AtomicInteger actualOccupiedDepth = new AtomicInteger();
    AtomicReference<Throwable> thrown = new AtomicReference<>();
    joinUninterruptibly(
        startThread(
            () -> {
              try {

   * access to the most-recently received one.
   */
  static class CountingRemovalListener<K, V> implements RemovalListener<K, V> {
    private final AtomicInteger count = new AtomicInteger();
    private volatile @Nullable RemovalNotification<K, V> lastNotification;

    @Override
    public void onRemoval(RemovalNotification<K, V> notification) {
      count.incrementAndGet();

  public void testRunIdempotency() throws Exception {
    int numThreads = 10;
    ExecutorService executor = newFixedThreadPool(numThreads);
    for (int i = 0; i < 1000; i++) {
      AtomicInteger counter = new AtomicInteger();
      TrustedListenableFutureTask<Integer> task =
          TrustedListenableFutureTask.create(counter::incrementAndGet);
      CyclicBarrier barrier = new CyclicBarrier(numThreads + 1);

    QueuingRemovalListener<String, String> removalListener = queuingRemovalListener();
    AtomicInteger computeCount = new AtomicInteger();
    AtomicInteger exceptionCount = new AtomicInteger();
    AtomicInteger computeNullCount = new AtomicInteger();
    @SuppressWarnings("CacheLoaderNull") // test of handling of erroneous implementation
    CacheLoader<String, String> countingIdentityLoader =

    QueuingRemovalListener<String, String> removalListener = queuingRemovalListener();
    AtomicInteger computeCount = new AtomicInteger();
    AtomicInteger exceptionCount = new AtomicInteger();
    AtomicInteger computeNullCount = new AtomicInteger();
    @SuppressWarnings("CacheLoaderNull") // test of handling of erroneous implementation
    CacheLoader<String, String> countingIdentityLoader =

    private TimeoutTask timeoutTask;
    private LogNotificationTarget logNotificationTarget;
    private final ConcurrentLinkedQueue<LogNotificationEvent> queue = new ConcurrentLinkedQueue<>();
    private final AtomicInteger size = new AtomicInteger(0);

    /**
     * Initializes the log notification timer.
     */
    @PostConstruct
    public void init() {
        logNotificationTarget = new LogNotificationTarget();

        ExecutorService executor = Executors.newFixedThreadPool(numThreads);
        CountDownLatch startLatch = new CountDownLatch(1);
        CountDownLatch doneLatch = new CountDownLatch(numThreads);
        AtomicInteger totalDrained = new AtomicInteger(0);

        for (int t = 0; t < numThreads; t++) {
            final int threadId = t;
            executor.submit(() -> {
                try {
                    startLatch.await();

    final Map<Integer, Map<String, MojoExecution>> mojos = new TreeMap<>();
    final Collection<BuildStep> predecessors = new HashSet<>();
    final Collection<BuildStep> successors = new HashSet<>();
    final AtomicInteger status = new AtomicInteger();
    final AtomicBoolean skip = new AtomicBoolean();
    volatile Exception exception;

    public BuildStep(String name, MavenProject project, Lifecycle.Phase phase) {

        options.numOfThreads = 4;
        options.cleanup = false;

        // Setup mock components with counter
        final AtomicInteger generateCallCount = new AtomicInteger(0);
        setupMockComponentsWithCounter(generateCallCount);

        Method processMethod = ThumbnailGenerator.class.getDeclaredMethod("process", ThumbnailGenerator.Options.class);

    }

    private final String name;
    private final AtomicReference<State> state = new AtomicReference<>(State.CLOSED);
    private final AtomicInteger consecutiveFailures = new AtomicInteger(0);
    private final AtomicInteger halfOpenSuccesses = new AtomicInteger(0);
    private final AtomicLong lastFailureTime = new AtomicLong(0);
    private final AtomicLong stateChangeTime = new AtomicLong(System.currentTimeMillis());