protected function getOutputByType($type)
    {
        switch ($type) {
            case 'stderr':
                $actual = $this->process->getErrorOutput();
                break;

            case 'all':
                $actual = $this->process->getOutput() . $this->process->getErrorOutput();
                break;

            case 'stdout':
            default:
                $actual = $this->process->getOutput();
                break;
        }

        return $actual;
    }