如何模拟$window单元测试AngularJS服务？

var services = angular.module('amdotcom.services',['ngResource']);

services.factory('homePageRes',['$resource','$window',function ($resource,$window) {
       var wdw = angular.element($window);
       return $resource('home/index',{
           height: wdw.height(),width: wdw.width()
       });
   }]);

services.factory('homePageLoader',['homePageRes','$q',function (homePageRes,$q) {
      return function () {
          var delay = $q.defer();
          homePageRes.get(function (homePage) {
              delay.resolve(homePage);
          },function () {
              delay.reject('Unable to fetch home page');
          });
          return delay.promise;
      };
  }]);

以下是我在介绍$window服务之前的测试.这些测试工作正常,但是一旦我介绍$window服务,我就无法嘲笑它.

describe('Services',function () {

    beforeEach(function () {
        module("amdotcom.services");
    });

    describe('homePageLoader',function () {
        var mockBackend,loader;

        beforeEach(inject(function ($httpBackend,homePageLoader) {
            mockBackend = $httpBackend;
            loader = homePageLoader;
        }));

        it('should return home page information',function () {
            mockBackend.expectGET('home/index?height=400&width=500').respond({ "Albums": [{ "Id": 2,"Name": "best shots" }] });

            var homePageData;

            var promise = loader();
            promise.then(function (homePg) {
                homePageData = homePg;
            });

            expect(homePageData).toBeUndefined();

            mockBackend.flush();

            expect(homePageData.Albums[0].Id).toEqual(2);
            expect(homePageData.Albums[0].Name).toEqual("best shots");
        });

        afterEach(function () {
            mockBackend.verifyNoOutstandingExpectation();
            mockBackend.verifyNoOutstandingRequest();
        });
    });
});

我收到错误说：TypeError：’undefined’不是函数(评估’wdw.height()’)

我尝试使用$provider和spyOn方法,但没有一个工作.请帮忙.

阿伦