title: Symfony2 demo testing issues
body: <p>I just installed the last version of phpunit and when I run the demo test with:</p>
  
  <pre><code>bin/phpunit src/Acme/DemoBundle/Tests/
  </code></pre>
  
  <p>I get this problems:</p>
  
  <pre><code>1) Acme\DemoBundle\Tests\Controller\DemoControllerTest::testIndex
  RuntimeException: Unable to guess the Kernel directory.
  </code></pre>
  
  <p>and the lines where the kernel is citated</p>
  
  <p>Any ideas about why does this DEMO TEST doesn't works?</p>