@Test
public void delegate() throws Exception {

  final ExecutorService exec = mock( ExecutorService.class );
  final DelegatedListenableExecutor delegatedListenableExecutor = new DelegatedListenableExecutor( exec );
  final ListeningExecutorService delegate = delegatedListenableExecutor.delegate();
  final Callable callable = mock( Callable.class );
  delegate.submit( callable );
  verify( exec, times( 1 ) ).execute( any( Runnable.class ) );
}