无法使用带有karma / jasmine的Angular2注入HTTP服务：未捕获的ReferenceError：未定义区域

Question

在构建期间，业力报告

Chrome 55.0.2883 (Windows 7 0.0.0) ERROR
  Uncaught ReferenceError: Zone is not defined

问题追溯到＆＃34; node_modules \ @angular \ core \ testing \ fake_async.js＆＃34;文件。我使用的是Angular 2.2.1及其Ionic2-RC4项目。

我正在尝试测试HTTP服务。以下是spec文件的内容：

import { TestBed, async, inject } from '@angular/core/testing';
import { BaseRequestOptions, HttpModule, Http, Response, ResponseOptions } from '@angular/http';
import { MockBackend } from '@angular/http/testing';
import { TestService } from './test-service';

describe('Bible Service', () => {
    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [HttpModule],
            providers: [
                TestService,
                {
                    provide: Http,
                    useFactory: (mockBackend, options) => {
                        return new Http(mockBackend, options);
                    },
                    deps: [MockBackend, BaseRequestOptions]
                },
                MockBackend,
                BaseRequestOptions
            ]
        });
    });

    it('should get a verse', () => {
        inject([TestService, MockBackend], (service, mockBackend) => {
            expect(service.getTest()).toBe("yes");
        });
    });
});

如果我不包含beforeEach，karma会正确运行该文件，因此问题与注入代码有关。任何帮助将不胜感激。

这是test-service.ts文件：

import { Injectable } from "@angular/core";
import { Http } from "@angular/http";

@Injectable()
export class TestService
{
    constructor(private http: Http)
    {
    }
    getTest()
    {
        return "yes";
    }
}