Unable to return json in symfony 2

This is my controller

public function index2Action($name)    {     $em = $this->getDoctrine()->getEntityManager();  $test = $em->getRepository('RestWebServiceBundle:Test')->findall();  return new Response(json_encode(array('locations' => $test)));    }

When I go to the URL I get:

{"locations":[{}]}

However when I use:

public function index2Action($name)    {   $name ="Adam";  return new Response(json_encode(array('locations' => $name)));    }

I get the JSON.

What am I doing wrong? I am trying to get JSON in the first scenario.

UPDATE: I have verified that the $test variable is indeed not empty and when I do a print_r on it, it shows me the following:

Array(    [0] => Rest\WebServiceBundle\Entity\Test Object        (            [id:protected] => 1            [title:protected] => test title            [author:protected] => test author            [blog:protected] => this is the blog            [tags:protected] =>             [comments:protected] =>             [created:protected] => DateTime Object                (                    [date] => 2012-05-13 00:00:00                    [timezone_type] => 3                    [timezone] => America/Chicago                )            [updated:protected] => DateTime Object                (                    [date] => 2012-05-13 00:00:00                    [timezone_type] => 3                    [timezone] => America/Chicago                )        ))null