title: symfony 2 phpunit - how to untick checkbox in form field
body: <p>This should be an easy one but I can't find the answer anywhere.
  I'm using Symfony 2 with phpunit to test my code.
  Its easy enough to get phpunit to tick a checkbox while running tests:</p>
  
  <pre><code>$form['mycompanyname_companybundle_editsomethingtype[locked]']-&gt;tick();
  </code></pre>
  
  <p>But how do I get it to 'untick' a checkbox?</p>