Why doesn't Backbone Collection fetch return a promise

问题

The following example code works well:

Auth_controller.prototype.isLogged = function(){ 
    //Check if the user is authenticated 
    var getAuthStatus = this.auth_model.fetch(); 
    return getAuthStatus; 
}; 

Auth_controller.prototype.redirect = function(fragment, args, next){ 

    var getAuthStatus = this.isLogged(); 
    var self = this; 

    $.when(getAuthStatus).then(function(response){ 
        //Do something with the response 
    }
});

This doesn't seem to work for a Collection though.
When I console log the collection, I get an empty collection back.

I know that I can use the success callback function from within the method (tested that already), but I don't want to do that, because I want the function to return a promise that I can call from other functions as well.
Edit -> No, sorry it doesn't work in the success callback either so it seems.

Any suggestions for a workaround ?

Edit;

This image shows what is returned from the model and collection fetch methods.
Unless I'm doing something wrong that is obvious, I don't understand why this happens.
When console logging the returned response in the success callback, I see that the empty object as shown in the screenshot, gets populated.

Edit2:

This is what my collection looks like:

define([
  /*--- libraries ---*/
  'jquery',     
  'underscore', 
  'backbone', 

  /*--- model ---*/
  'models/users/role_model'

], function($, _, Backbone, 
                Role_model){

    var Role_collection = Backbone.Collection.extend({ 
        url: '/ingeb/api_v1/users/roles', 
        model: Role_model 
    }); 

    return Role_collection; 

});