Test standalone JS file in Jasmine/Node.js

I have a standalone javascript file, cacheBustingInterceptor.js in a node.js app. It is a service in a factory pattern that is invoked by the app.js when the app holds.

/** 
* Intercept the http request 
* If the config.url is from upload or templates and is a html file
* append the cacheBusting Param
* If the template url has query param exisitng
* append &_dt=epochtime else append ?_dt=epochtime
*/
var cacheBustingInterceptor = {
CacheBustingService: CacheBustingServiceFactory
};

function CacheBustingServiceFactory() {
function CacheBustingService() {}

var possibleHtmlPaths = ['templates', 'upload'];
CacheBustingService.prototype.appendCacheBustingParam = function(templateUrl) {
    for (var index = 0; index != possibleHtmlPaths.length; index++) {

        // check if the url has is .html and from upload and templates
        var addCacheBusting = templateUrl.indexOf(possibleHtmlPaths[index]) != - 1 && 
            templateUrl.indexOf('.html') != - 1;
        var hasQueryParams = templateUrl.indexOf('?') != -1;

        if (addCacheBusting) {
            if (hasQueryParams) {
                return templateUrl + window.appendCacheBustingParam;
            } else {
                return templateUrl + window.cacheBustingParam;
            }
        } 
    }
    return templateUrl;
};

CacheBustingService.prototype.interceptRequest = function() {
    var _this = this;
    var cacheBuster = {
        request: function (config) {
            config.url = _this.appendCacheBustingParam(config.url);
            return config;
        }
    }
    return cacheBuster;
}

return CacheBustingService;

}

the way we invoke this is by adding a injector to the app.js in the config and push the factory to the configs.

like so,

   app. config([''$httpProvider', function ($httpProvider) {
    $httpProvider.interceptors.push('templateCacheBustingInjector');

  app.factory('templateCacheBustingInjector', ['$injector', function 
    ($injector) {
    var CacheBustingService = 
         $injector.invoke(cacheBustingInterceptor.CacheBustingService);
         var cacheBustingService = new CacheBustingService();

    return cacheBustingService.interceptRequest();
  }]);

Now this all works fine but I want to unit test the method 'appendCacheBustingParam' in the cacheBustingInterceptor.js and running out of ideas to invoke it from the jasmine unit test

Things tired: 1. invoking the way I invoked in the app.js, but I get service injection error or provider error 2. load the js file using require but require is not supported and I tried using browsify, however, that too doesnot help.

  require('../main/webapp/media/scripts/cacheBustingInterceptor.js'); 

  fdescribe('Cache Busting Service', function() {
      var cacheBustingService;
       var $injector;

beforeEach((inject(function (_$injector_) {
    $injector = _$injector_;
   $injector.get(cacheBustingInterceptor.CacheBustingService);
    // var CacheBustingService = $injector.invoke(cacheBustingInterceptor.CacheBustingService);
})));

it('Test appendCacheBustingParam', function() {
    cacheBustingService = new CacheBustingService();
    spyOn(cacheBustingService.prototype, 'appendCacheBustingParam');
    expect(cacheBustingService.prototype).toHaveBeenCalled();
});

});

from Test standalone JS file in Jasmine/Node.js