AngularJS+Jasmine:$httpBackend 没有按预期工作

问题描述

我正在使用 Jasmine 和 Karma 来测试我基于 Angular 构建的应用.

I'm using Jasmine with Karma to test my app built on Angular.

我必须测试加载用户数据的服务，并且我正在使用 $httpBackend 来模拟响应.但是，当我运行测试时，出现了两个错误:

I've to test a service that loads user data and I'm using $httpBackend to mock the responses.However, when I run the test, I got two errors:

• 错误:没有待处理的刷新请求！
• 错误:未满足的请求:GET https://api.github.com/users/wilk

模块:

'use strict';

app.service ('UserService', ['$resource', '$q', 'GITHUB_API_URL', function ($resource, $q, GITHUB_API_URL) {
  var userResource = $resource (GITHUB_API_URL + '/users/:user', {user: '@user'}) ,
      userModel = {};

  return {
    data: function () {
        return userModel;
    } ,
    populate: function (user) {
      var deferred = $q.defer () ,
          userRequest = userResource.get ({user: user});

      $q
          .when (userRequest.$promise)
          .then (function (data) {
              userModel = data;
              deferred.resolve (data);
          });

      return deferred.promise;
    }
  };
}]);

测试:

'use strict';

describe ('Service: UserService', function () {
    beforeEach (module ('myApp'));

    var $appInjector = angular.injector (['myApp']) ,
        UserService = $appInjector.get ('UserService') ,
        GITHUB_API_URL = $appInjector.get ('GITHUB_API_URL') ,
        GITHUB_USER = $appInjector.get ('GITHUB_USER') ,
        $httpBackend;

    beforeEach (inject (function ($injector) {
        $httpBackend = $injector.get ('$httpBackend');

        $httpBackend
            .when ('GET', GITHUB_API_URL + '/users/' + GITHUB_USER)
            .respond ({
                login: GITHUB_USER ,
                id: 618009
            });
    }));

    afterEach (function () {
        $httpBackend.verifyNoOutstandingExpectation ();
        $httpBackend.verifyNoOutstandingRequest ();
    });

    describe ('when populate method is called', function () {
        it ('should returns user data', function () {
            $httpBackend.expectGET (GITHUB_API_URL + '/users/' + GITHUB_USER);

            UserService.populate (GITHUB_USER);
            $httpBackend.flush ();
            expect(UserService.data ()).toEqual ({
                login: GITHUB_USER ,
                id: 618009
            });

        });
    });
});

假设 GITHUB_API_URL 等于 'https://api.github.com/' 和 GITHUB_USER 等于 'wilk'.

Let's assume that GITHUB_API_URL is equal to 'https://api.github.com/' and GITHUB_USER is equal to 'wilk'.

我正在使用 Karma-Jasmine 0.1.5 和 AngularJS 1.2.6(使用 Angular Mocks 和 Scenario 1.2.6)运行此测试.

I'm running this test with Karma-Jasmine 0.1.5 and AngularJS 1.2.6 (with Angular Mocks and Scenario 1.2.6).

这段代码有什么问题?

推荐答案

我们分别说一下每个错误:

Let's talk about each error separately:

错误:没有待处理的刷新请求！

发生这种情况是因为没有通过 $httpBackend 发出请求，所以没有什么要刷新的.那是因为您在 $httpBackend 之前实例化了 UserService，所以 Angular 不知道它应该使用它而不是真正的 $http.如果您查看控制台，您会看到正在发送一个真正的请求.

That's happening because no request was made through $httpBackend, so there's nothing to flush. That's because you are instantiating UserService before $httpBackend and so Angular doesn't know it should use it instead of the real $http. If you check out the console you'll see that a real request is being sent.

错误:未满足的请求:GET https://api.github.com/users/wilk

同上原因.由于服务未使用 $httpBackend，因此您创建的期望从未实现.

Same reason as the above. Since $httpBackend isn't being used by the service, the expectation you've created is never fulfilled.

这是考虑到上述所有内容后重构的规范:

Here's your spec refactored after considering all of the above:

describe ('Service: UserService', function () {
    var UserService,
        GITHUB_API_URL,
        GITHUB_USER,
        $httpBackend;

    beforeEach(function() {
      module('plunker');

      inject(function( _$httpBackend_, _UserService_, _GITHUB_API_URL_, _GITHUB_USER_) {
        $httpBackend = _$httpBackend_;
        UserService = _UserService_;
        GITHUB_API_URL = _GITHUB_API_URL_;
        GITHUB_USER = _GITHUB_USER_;
      });
    });

    afterEach (function () {
        $httpBackend.verifyNoOutstandingExpectation ();
        $httpBackend.verifyNoOutstandingRequest ();
    });

    describe ('when populate method is called', function () {
        it ('should returns user data', function () {
            $httpBackend
              .whenGET(GITHUB_API_URL + '/users/' + GITHUB_USER)
              .respond ({
                  login: GITHUB_USER,
                  id: 618009
              }); 

            UserService.populate(GITHUB_USER);
            $httpBackend.flush();

            expect(UserService.data().login).toBe(GITHUB_USER);
            expect(UserService.data().id).toBe(618009);
        });
    });
});

Plunker

注意:我已经稍微改变了注入的方式，但是你的方式很好，只要你在其他一切之前创建 $httpBackend .

Note: I've changed the way things were being injected a little bit, but the way you are doing is just fine, as long as you create $httpBackend before everything else.

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