How to mock $window.location.href in Backbone Marionette unit test?

I have a function that when doesn't find anything stored in the cookie,redirects to some page specified as:

showEnrollRoute: function(){
            var username = Application.utils.getCookie("username");
            if(username != null || username != undefined){
                Application.vent.trigger("refresh:header");
                var channel = module.getChannel("counties");
                channel.then(function(channel){
                    channel.request("fetQuestions");
                }); 
            } else {
                console.log("Start");
                window.location.href= Application.getConfig("logoutSuccess");//error point
                console.log("End");
            }   
        }

The window.location.href is causing the unit-tests to fail.

Some of your tests did a full page reload.

I did some research and found out that I've to mock $window object in unit test to prevent reloading the page when running tests?

Can anyone please suggest a way to go about it? Thanks in advance!

EDIT: This problem is same but the question is different now. I have found out that the mocking the $window object inside test-case would stop the the error from happening. Can anyone please suggest a way to go about it?