Test fails in ember

I'm facing some problems figuring out how to pass a test in Ember.

The thing is, I'm trying to use NProgress in my project, but I can't pass my tests.

I'm following this example to create a mixing for it, and everything is working fine, besides the tests.

That's the mixing I created:

import Ember from 'ember';
NProgress.configure({ showSpinner: true });

export default Ember.Mixin.create({  
  actions: {
    loading() {
      if(!Ember.$('.nprogress-busy').length) {
            if(Ember.$('#content').length) {
              Ember.$('#content').removeClass('fadeIn');
              Ember.$('#content').addClass('animated fadeOut');
            }
            if(Ember.$('#page-content-wrapper').length) {
              Ember.$('#page-content-wrapper').removeClass('fadeIn');
              Ember.$('#page-content-wrapper').addClass('animated fadeOut');
            } 
          NProgress.start();
        }   
      this.router.one('didTransition', function () {
          window.scrollTo(0, 0);
          setTimeout(function(){
            if(Ember.$('#content').length) {
              Ember.$('#content').removeClass('fadeOut');
              Ember.$('#content').addClass('animated fadeIn');
            }
            if(Ember.$('#page-content-wrapper').length) {
              Ember.$('#page-content-wrapper').removeClass('fadeOut');
              Ember.$('#page-content-wrapper').addClass('animated fadeIn');
            }
          }, 1000);
          NProgress.done();
            return true;
      });
    }, 
      error() {
        NProgress.done();
        return true;
      }
  }
});

And that's what is failing:

not ok 80 PhantomJS 2.0 - JSHint - mixins: mixins/loading-indicator.js should pass jshint
---
    actual: >
        false
    expected: >
        true
    message: >
        mixins/loading-indicator.js should pass jshint.
        mixins/loading-indicator.js: line 2, col 1, 'NProgress' is not defined.
        mixins/loading-indicator.js: line 16, col 11, 'NProgress' is not defined.
        mixins/loading-indicator.js: line 30, col 11, 'NProgress' is not defined.
        mixins/loading-indicator.js: line 35, col 9, 'NProgress' is not defined.

        4 errors
    Log: |
...

As you can see, I can use NProgress without any problems on the application, but as I'm not declaring NProgress anywhere the test fails.

Does anyone have an idea about how I could pass it?

I know there are similar components in ember, but I chose to use NProgress because I can set when I want it to start, and when I want it finish. I didn't want to use a progress bar where I would need to set a time for the animation.

Thanks in advance!