public function testToString()
{
$url = new Url('http://thumbor-server:8888', 'MY_SECURE_KEY', 'my/big/image.jpg', array('fit-in', '560x420', 'filters:fill(green)'));
$this->assertEquals('http://thumbor-server:8888/bDv76lTvUdX6vORS96scx7P185c=/fit-in/560x420/filters:fill(green)/my/big/image.jpg', "{$url}");
}