@Override
    public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {
        throw new UnsupportedOperationException();
    }
@Test(expected = UnsupportedOperationException.class)
    public void invokeAll() throws Exception {
        newManagedExecutorService().invokeAll(Collections.singleton(() -> null));
    }