Does not work in subdirectory

[mike-2013]

For example my url is http://localhost/test/

    $app = new App();
    
    $home = new Route('/', function($req, $res) {
        return $res->write('Hello World!');
    });
    
    $app->add($home);
    $app->run();

I'm not an expert but it has something to do with Request::url()
Is there an option to set manually url path?