}

  public void testUncaughtExceptionHandler_custom() {
    assertEquals(
        UNCAUGHT_EXCEPTION_HANDLER,
        builder
            .setUncaughtExceptionHandler(UNCAUGHT_EXCEPTION_HANDLER)
            .build()
            .newThread(monitoredRunnable)
            .getUncaughtExceptionHandler());
  }

  public void testBuildMutateBuild() {

  }

  public void testUncaughtExceptionHandler_custom() {
    assertEquals(
        UNCAUGHT_EXCEPTION_HANDLER,
        builder
            .setUncaughtExceptionHandler(UNCAUGHT_EXCEPTION_HANDLER)
            .build()
            .newThread(monitoredRunnable)
            .getUncaughtExceptionHandler());
  }

  public void testBuildMutateBuild() {

    }

    // Test setUncaughtExceptionHandler
    @Test
    public void test_setUncaughtExceptionHandler() {
        final AtomicBoolean handlerCalled = new AtomicBoolean(false);
        final Thread.UncaughtExceptionHandler handler = (t, e) -> handlerCalled.set(true);

        indexUpdater.setUncaughtExceptionHandler(handler);

      new Executor() {
        @Override
        public void execute(Runnable command) {
          executionThread = new Thread(command);
          executionThread.setUncaughtExceptionHandler(
              (thread, throwable) -> thrownByExecutionThread = throwable);
          executionThread.start();
        }
      };

  @Override
  protected final void tearDown() {

            try {
              cacheRef.get().getUnchecked(3);
            } finally {
              doneSignal.countDown();
            }
          }
        };
    thread.setUncaughtExceptionHandler((t, throwable) -> {});
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);
    if (!done) {
      StringBuilder builder = new StringBuilder();

            try {
              cacheRef.get().getUnchecked(3);
            } finally {
              doneSignal.countDown();
            }
          }
        };
    thread.setUncaughtExceptionHandler((t, throwable) -> {});
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);
    if (!done) {
      StringBuilder builder = new StringBuilder();

      new Executor() {
        @Override
        public void execute(Runnable command) {
          executionThread = new Thread(command);
          executionThread.setUncaughtExceptionHandler(
              (thread, throwable) -> thrownByExecutionThread = throwable);
          executionThread.start();
        }
      };

  @Override
  protected final void tearDown() {

          });
    }
  }

  private void invokeOnExecutionThreadForTest(Runnable runnable) {
    executionThread = new Thread(runnable);
    executionThread.setUncaughtExceptionHandler(
        (thread, throwable) -> thrownByExecutionThread = throwable);
    executionThread.start();
  }

  private static void throwIfSet(Throwable t) throws Throwable {
    if (t != null) {

          });
    }
  }

  private void invokeOnExecutionThreadForTest(Runnable runnable) {
    executionThread = new Thread(runnable);
    executionThread.setUncaughtExceptionHandler(
        (thread, throwable) -> thrownByExecutionThread = throwable);
    executionThread.start();
  }

  private static void throwIfSet(Throwable t) throws Throwable {
    if (t != null) {

    List<Thread> threads = new ArrayList<>(numThreads);
    List<Throwable> exceptions = new ArrayList<>(numThreads);
    for (int i = 0; i < numThreads; i++) {
      Thread thread = new Thread(task);
      thread.setUncaughtExceptionHandler((t, throwable) -> exceptions.add(throwable));
      threads.add(thread);
    }
    for (Thread t : threads) {
      t.start();
    }
    for (Thread t : threads) {