lithium\action\Request::type PHP Method

    public function type($type = null)
    {
        if (!$type && !empty($this->params['type'])) {
            $type = $this->params['type'];
        }
        return parent::type($type);
    }

 public function testRequestTypeFromHeader()
 {
     $request = new Request(array('env' => array('CONTENT_TYPE' => 'json')));
     $this->assertEqual('json', $request->type());
 }