$output->writeln(
    (int) (new QuestionHelper())->ask(
         $input, $output, new ConfirmationQuestion('yes or no?', false)
    )
);

I expect running this as yes | ./bin/console foo will output 1, but outputs 0. Problem is QuestionHelper slaps there always default value when it detects noninteractive mode.

Maybe non interactive mode detection could be improved, since yes command clearly interacts with application.