title: How to catch exceptions with phpspec2
body: <p>I'm trying to catch exceptions with my spec but i can't make it works. This is my code:</p>
  
  <pre><code>$this-&gt;edit('updated comment', $comment, $user)
      -&gt;shouldReturnAnInstanceOf('\Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException');
  </code></pre>
  
  <p>What i'm doing wrong?</p>