public function testAllowFailingCommand()
{
$output = new BufferedOutput();
$executor = new ProcessExecutor($output, 60);
$expectedOutput = "ls: cannot access '/no-such-file': No such file or directory\n";
$exitCode = $executor->execute('LC_ALL=C ls /no-such-file', null, true);
$this->assertEquals(2, $exitCode);
$this->assertEquals($expectedOutput, $output->fetch());
}