/**
  * @expectedException \Symfony\Component\Filesystem\Exception\IOException
  */
 public function testChgrpFail()
 {
     $this->markAsSkippedIfPosixIsMissing();
     $dir = $this->workspace . DIRECTORY_SEPARATOR . 'dir';
     mkdir($dir);
     $this->filesystem->chgrp($dir, 'user' . time() . mt_rand(1000, 9999));
 }