使用 jasmine angular2 注入私人服务的单元测试

Question

我在尝试对 angular 服务进行单元测试时遇到问题。我想验证此服务是否正确调用注入其中的另一个服务。

假设我有这个注入 ServiceInjected 的 ServiceToTest：

服务测试.service.ts

@Injectable()
export class ServiceToTest  {
    constructor(private _si: ServiceInjected) {}
    public init() {
      this._si.configure();
    }

}

ServiceInjected。service.ts

@Injectable()
export class ServiceInjected {
    constructor() {}
    public configure() {
    /*Some actions*/
    }

}

有了这些服务，现在我编写我的单元测试：

const serviceInjectedStub = {
  configure(): void {}
}


describe('ServiceToTest service Test', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [ServiceToTest ,
        { provide: ServiceInjected, useValue: serviceInjectedStub }]
    });
  });
  
  it('should be initialize the service injected', inject([ServiceToTest],
    (tService: ServiceToTest) => {
      spyOn(serviceInjectedStub, 'configure');
      tService.init();
      expect(serviceInjectedStub.configure).toHaveBeenCalled();
    }));

我原以为我的测试是阳性的，但是我收到以下错误：

预期已调用间谍配置。

另一方面，如果我以这种方式设置注入服务 public 它工作正常：

private _si: ServiceInjected by public si: ServiceInjected

Answer 1

使用这个：

spyOn(serviceInjectedStub, 'configure').and.returnValue(配置); // 配置是一个 mock

Answer 2

您不会监视与您的 TestBed 相关的服务。从您的测试台获取服务

beforeEach(() => {
  TestBed.configureTestingModule({
    providers: [ServiceToTest ,
      { provide: ServiceInjected, useValue: serviceInjectedStub }]
  });
  injectedService = TestBed.get(ServiceInjected);
});

并对其进行测试

spyOn(injectedService, 'configure').and.returnValue(/* return same data type here */);
// ...
expect(injectedService.configure).toHaveBeenCalled();

Answer 3

或者您可以使用 jasmine.createSpyObj 并为其提供 useValue，如下所示：

describe('YourComponent', () => {

  let serviceInjectedSpy: jasmine.SpyObj<ServiceInjected>;

  beforeEach(async(() => {

     // notice here
     serviceInjectedSpy = jasmine.createSpyObj('ServiceInjected', ['configure']);

     TestBed.configureTestingModule({
        declarations: [YourComponent],
        providers: [
           {provide: ServiceInjected, useValue: serviceInjectedSpy}
        ],
        imports: [
         ...
        ]
     }).compileComponents().then(() => {
        fixture = TestBed.createComponent(YourComponent);
        component = fixture.componentInstance;
     });
  });

  it('should assert my test', () => {
       serviceInjectedSpy.configure.and.returnValue(/* what you want */);
       component.init();
       expect(serviceInjectedSpy.configure).toHaveBeenCalled();
  });

});

Answer 4

从 Angular 9 你应该使用 TestBed.inject;那么您就不需要在提供商列表中添加该服务了。

let injectedService: ServiceInjected;
beforeEach(() => {
  TestBed.configureTestingModule({
    providers: [ServiceToTest]
  });
  injectedService = TestBed.inject(ServiceInjected);
});

然后监视它

// if you want to ignore the call
spyOn(injectedService, 'configure').and.callThrough();
// if you need to set stuff up
spyOn(injectedService, 'configure').and.callFake(async () => {/* some fake stuff */});

并进行检查

expect(injectedService.configure).toHaveBeenCalled();
// ...

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