Cannot create connection mongo use default setting.

I use this config to connect mongodb

$di->set('mongo', function() use ($config) { $mongo = new MongoClient(); return $mongo->selectDb("test"); }, true);

but I'm still get error 500 when use this connect. My mongo is success connect use command 'mongo' in terminal I use this config to connect mongodb.

And what error you have in logs ?

I don't see anything. So, if want to use this, Do I must install php mongo driver?

edited May '16

What you mean you don't see anything ? If you have error 500 then you must have something in php/apache/nginx error logs. There can't be error without any message.

Well it's obvious that mongo driver it's necessary. But be aware that on php7 mongo driver in php changed and in phalcon mongo adapter is not adapted to it yet.