/**
  * @param string $variable
  * @param mixed $callback
  * @return $this
  */
 public function convert($variable, $callback)
 {
     if (is_string($callback)) {
         $callback = $this->callback_prefix . ":" . $callback;
     }
     parent::convert($variable, $callback);
     return $this;
 }
 public function testConvert()
 {
     $controllers = new ControllerCollection(new Route());
     $controllers->convert('id', '1');
     $controller = $controllers->match('/{id}/{name}/{extra}', function () {
     })->convert('name', 'Fabien')->convert('extra', 'Symfony');
     $controllers->convert('extra', 'Twig');
     $this->assertEquals(array('id' => '1', 'name' => 'Fabien', 'extra' => 'Twig'), $controller->getRoute()->getOption('_converters'));
 }