方法返回html symfony2

I try to send a html code in symfony2 like this :

public function testAction()
{
  $html = '<input type="text">'
  return $this->render('TestBundle:Default:index.htlm.twig',array(
  'html' => $html,
  ));
}

When I use html variable in the page index.html.twig like this : {{ html }} the result is

<input type="text">

But I do not want this result. the result that I want is that the page index.html.twig display me the input (the text area).

An answer from the doc : http://twig.sensiolabs.org/doc/api.html#escaper-extension

The escaper extension adds automatic output escaping to Twig. It defines a tag, autoescape, and a filter, raw.

When creating the escaper extension, you can switch on or off the global output escaping strategy:

$escaper = new Twig_Extension_Escaper('html');
$twig->addExtension($escaper);

If set to html, all variables in templates are escaped (using the html escaping strategy), except those using the raw filter:

{{ article.to_html|raw }}

You can also change the escaping mode locally by using the autoescape tag (see the autoescape doc for the syntax used before Twig 1.8):

{% autoescape 'html' %}
    {{ var }}
    {{ var|raw }}      {# var won't be escaped #}
    {{ var|escape }}   {# var won't be double-escaped #}
{% endautoescape %}