public void testInvokeAnyImpl() throws Exception {
    ListeningExecutorService e = newDirectExecutorService();
    try {
      List<Callable<String>> l = new ArrayList<>();
      l.add(new StringTask());
      l.add(new StringTask());
      String result = invokeAnyImpl(e, l, false, 0, NANOSECONDS);
      assertSame(TEST_STRING, result);
    } finally {
      joinPool(e);
    }
  }

  public void testInvokeAnyImpl() throws Exception {
    ListeningExecutorService e = newDirectExecutorService();
    try {
      List<Callable<String>> l = new ArrayList<>();
      l.add(new StringTask());
      l.add(new StringTask());
      String result = invokeAnyImpl(e, l, false, 0, NANOSECONDS);
      assertSame(TEST_STRING, result);
    } finally {
      joinPool(e);
    }
  }

    @Override
    public Object call() {
      return Boolean.TRUE;
    }
  }

  public static final String TEST_STRING = "a test string";

  public static class StringTask implements Callable<String> {
    @Override
    public String call() {
      return TEST_STRING;
    }
  }

  public Callable<String> latchAwaitingStringTask(CountDownLatch latch) {