模拟服务时Angular2测试失败 [英] Angular2 test fail when mocking a service

问题描述

尝试测试具有服务依赖关系的组件，该组件调用rest API，并使用扩展真实服务的类制作了该服务的模拟版本.

Trying to test a component with a service dependency that call rest API, made a mocked version of the service, with a class that extends the real service.

现在，如果我用模拟的提供程序覆盖提供程序，则因果报应程序会出现奇怪的错误，首先是2个不存在的文件(实际上不应该存在)的404，然后是"{originalErr:{}}".我的意思是至少告诉我我做错了什么:)

Now if I override the provider with the mocked one, weird error comes out of karma reporter, first 404 for 2 not existing files (that really should not exist) and then "{originalErr: {}}". I mean at least tell me what I've done wrong :)

 describe('App: HeaderComponent', () => {
      it('should get categories on initialization', 
        async(
          inject([TestComponentBuilder], (builder: TestComponentBuilder) => {
            let fixture: ComponentFixture<HeaderComponent>;
            expect(builder).toBeDefined();
            return builder
              .overrideProviders(HeaderComponent, [{provide: CategoryService, useClass: MockCategoryService}])
              .createAsync(HeaderComponent).then((_fixture) => {
                fixture = _fixture;
                let $el = fixture.debugElement;
                let el = $el.nativeElement;
                let component = $el.componentInstance;
                component.ngOnInit();
                fixture.detectChanges();
                expect(el.querySelector('a')).toHaveText('Electric');
              });
          })
        )
      );
    });

输出:

01 08 2016 11:58:29.684:WARN [karma]: No captured browser, open http://localhost:9876/
01 08 2016 11:58:29.713:INFO [karma]: Karma v1.1.2 server started at http://localhost:9876/
01 08 2016 11:58:29.718:INFO [launcher]: Launching browser Chrome with unlimited concurrency
01 08 2016 11:58:29.729:INFO [launcher]: Starting browser Chrome
01 08 2016 11:58:32.277:INFO [Chrome 52.0.2743 (Windows 10 0.0.0)]: Connected on socket /#Semtu7s7yqM-TW0GAAAA with id 14496897
01 08 2016 11:58:35.315:WARN [web-server]: 404: /base/dist/app/shared/services.js
01 08 2016 11:58:35.318:WARN [web-server]: 404: /base/dist/app/shared/services/mocks.js
Chrome 52.0.2743 (Windows 10 0.0.0) ERROR
  {
    "originalErr": {}
  }

---

如果我删除该行，则测试通过(但不执行"then(...)"代码块):

---

If i remove the line the test pass (but doesn't execute the "then(...)" code block):

overrideProviders(HeaderComponent, [{provide: CategoryService, useClass: MockCategoryService}])

推荐答案

好吧，万一有人遇到相同的问题，原来应该导入"ts"文件本身，而不是通过桶.意思是你应该这样写:

Well, in case anybody encounter the same problem, it turned out one should import the "ts" file itself, not through a barrel. meaning you should write something like this:

import { CategoryService } from '../../shared/services/category/category.service';
import { MockCategoryService } from '../../shared/services/category/category.service.mock';

代替

import { CategoryService, MockCategoryService } from '../../shared/services/category';

即使您在导出文件的目录中有index.ts.

even though you have index.ts in the directory that export the files.

野蛮人，嗯?

仍然，存在不执行异步操作的问题，我不知道为什么

Still the problem of not executing the async operation exist, I don't know why

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