模拟localStorage.getItem时出现错误“预期功能”

Question

I'm trying to mock calls to localStorage.getItem, but getting error "Function expected". Here is my test code:

describe("AuthService Tests", function() {
 var authSvc, httpBackend, scope;

 var fakeItem = "{\"access_token\":\"giant_access_token\",\"token_type\":\"bearer\",\"expires_in\":1209599,\".issued\":\"Thu, 11 Feb 2016 13:22:45 GMT\",\".expires\":\"Thu, 25 Feb 2016 13:22:45 GMT\",\"accountType\":\"Administrator\",\"certifiedForAccess\":true}";

 var returnFakeToken = function(key) { return fakeItem; }

 beforeEach(module('app'));

 beforeEach(inject(function (_AuthService_, $q, $rootScope, $httpBackend, $state, _config_, _messages_) {
    scope = $rootScope.$new();
    spyOn(localStorage, 'getItem').and.callFake(returnFakeToken);

    authSvc = _AuthService_;

    httpBackend = $httpBackend;
 }));

 describe('Test suite 1', function () {

    it('should return true if user is Administrator', function () {

        var result = authSvc.isAdministrator(); // error here
        expect(result).toBe(true);
    });
 });
});

Service under test:

(function () {
'use strict';

angular
    .module('app.services')
    .factory('AuthService', AuthService);

AuthService.$inject = ['$q', '$rootScope', '$http', '$state', 'config', 'messages'];

function AuthService($q, $rootScope, $http, $state, config, messages) {
    var userIdKey = 'userId';
    var tokenKey = 'tokenKey';
    var userAuthKey = 'userAuth';

    var svc = {
        isAdministrator: isAdministrator
    };

    return svc;

    function isAdministrator() {
        var item = localStorage.getItem(tokenKey); // eror here
        var jsonparse = JSON.parse(item);
        return jsonparse.accountType == 'Administrator';
    }
})();

When I run tests, my mocked function returnFakeToken hadn't even been called and I got error (lines of code where error occured are marked with comments):

TypeError: Function expected

What am I doing wrong?

Thanks!

Answer 1

You don't need to spy on localStorage . It is a function that is built into the browser as part of the HTML5 standard. What you should be testing is that your service returns the expected value. Also, you may need to mock out localStorage if you are testing in PhantomJS.