title: PhpUnit form does not submit, no error
body: <p>I'm doing a functional test in PhpUnit to test simple modal window functionality which has only one field and two buttons (i have tried various ways so the code may be not clean, I'm pasting just to show the idea):</p>
  
  <pre><code>    $form = $crawler
           // find all buttons with the text "Pridėti"
          -&gt;filter('button:contains("Pridėti")') 
          -&gt;eq(0)
          -&gt;form()// select the first button in the list
      ;
  
      $form['appbundle_classinfo[name]'] = '5a';
      $crawler = $client-&gt;submit($form);
  
      //It doesn't even save to database 
      $container = self::$kernel-&gt;getContainer();
      $em = $container-&gt;get('doctrine')-&gt;getManager();
      $classinfo = $em-&gt;getRepository('AppBundle:ClassInfo');
  
      //Echoes modal window
      echo $client-&gt;getResponse()-&gt;getContent() ;die;
  </code></pre>
  
  <p>I also tried to var_dump the form, it shows that the value is added to form:
  string(25) "appbundle_classinfo[name]"
            ["value":protected]=>
            string(2) "5a"</p>
  
  <p>So the form is not submitted. Can you help me find out why?</p>