TypeScript/Angular $q 立即解决延迟不起作用

Question

我有一个在 TypeScript 中创建的 Angular Service 类，我这个服务有一个加载方法。这个特定的服务，它正在加载的列表实际上是硬编码的，所以我不需要从任何后端服务加载它。我希望 load 方法返回一个承诺，因为我希望服务看起来像我在课堂上拥有的其他数据服务。

这是我拥有的数据服务

module MyApplication.Data {

    export interface IDestinationService {

        load(): ng.IPromise<Array<MyApplication.Models.Destination>>;

    }

    export class DestinationService implements IDestinationService {

        items: Array<MyApplication.Models.Destination>;

        constructor($http: ng.IHttpService, private $q: ng.IQService) {
            this.items = new Array<MyApplication.Models.Destination>();
            this.items.push(new MyApplication.Models.Destination());
            this.items.push(new MyApplication.Models.Destination());
            this.items[0].Id = 2;
            this.items[0].Description = 'Item 1';
            this.items[1].Id = 3;
            this.items[1].Description = 'Item 2';
        }

        load(): ng.IPromise<Array<MyApplication.Models.Destination>> {
            var defer = this.$q.defer();

            defer.resolve(this.items);

            return defer.promise;
        }

    }

}

根据我的阅读，这应该可以使服务正常工作。它会返回一个promise，但是当它返回时promise会立即被解析，所以then方法应该被触发。

我有一个 Jasmine 测试类，如下所示：

module MyApplication.Tests {

    describe('Data', () => {

        describe('Destination', () => {

            var $http: ng.IHttpService;
            var $httpBackend: ng.IHttpBackendService;
            var $q: ng.IQService;

            beforeEach(inject((_$http_: ng.IHttpService, _$httpBackend_: ng.IHttpBackendService, _$q_: ng.IQService) => {
                $http = _$http_;
                $httpBackend = _$httpBackend_;
                $q = _$q_;
            }));

            describe('', () => {
                var results: Array<MyApplication.Models.Destination>;

                beforeEach((done) => {
                    var service = new MyApplication.Data.DestinationService($http, $q);
                    service.load()
                        .then((result) => {
                            results = result;
                            done();
                        });
                });

                it('Returns Planning Brokers list', () => {
                    expect(results.length).toBe(2);
                });

            });

        });

    });

}

但是当我运行这个测试时，我从 Jasmine 收到了一个异步超时错误，因为 then 方法永远不会触发。我怎样才能让它正常工作。

Answer 1

您不应该需要第二个 describe 和 beforeEach 块。使用rootScope.$digest 解决承诺，并像这样重组您的测试代码：

describe('Data', () => {

    describe('Destination', () => {

        var $http: ng.IHttpService;
        var $httpBackend: ng.IHttpBackendService;
        var $q: ng.IQService;

        beforeEach(inject((_$http_: ng.IHttpService, _$httpBackend_: ng.IHttpBackendService, _$q_: ng.IQService) => {
            $http = _$http_;
            $httpBackend = _$httpBackend_;
            $q = _$q_;
        }));

        it('Returns Planning Brokers list', () => {
            var results: Array<MyApplication.Models.Destination>;

            var service = new MyApplication.Data.DestinationService($http, $q);
            service.load().then((results) => {
                expect(results.length).toBe(2);
            });

            $rootScope.$digest();
        });

    });

});