Question

我正在用 angular 做单元测试。在 component.ts 中的 ngOnInit 中，我有一个服务方法调用，如下所示：

ngOnInit(){
   this.DomainManagementService.getVerifiedDomains().then(res => {
      this.claimedDomains = res.filter(domain => {
        return domain.status === 'claimed';
      });
    });
}

我从 getVerifiedDomains() 方法获取数据，然后应用过滤方法仅过滤掉声明的域。最后，我将过滤后的域存储在 this.claimedDomains 中。现在我需要测试 this.claimedDomains 的长度是否大于 0。这个怎么做？请帮我写测试用例。

Answer 1

你必须先模拟 domainMainagementService，我会使用 jasmine.createSpyObj。

....
let mockDomainManagementService: jasmine.SpyObj<DomainManagementService>;
....
beforeEach(waitForAsync(() => {
   mockDomainManagementService = jasmine.createSpyObj<DomainManagementService>('DomainManagementService', ['getVerifiedDomains']);
   TestBed.configureTestingModule({
     ....
     providers: [{ provide: DomainManagementService, useValue: mockDomainManagementService }],
   }).compileComponents();
   // Make sure this is there before the first fixture.detectChanges().
   // The first fixture.detectChanges() calls ngOnInit.
   // Mock the return value here.
   mockDomainManagementService.getVerifiedDomains.and.returnValue(Promise.resolve([
     { status: 'claimed' },
  ]))
}));

it('should set claimedDomains', async () => {
   // wait until all promises are resolved with fixture.whenStable()
   await fixture.whenStable();
   expect(component.claimedDomains.length).toBe(1);
});

Answer 2

您需要这样做来模拟您的服务调用：

// This will create a function that will inject the service in your test
function setup() {
    const domainManagementService = fixture.debugElement.injector.get(DomainManagementService);

    return { domainManagementService };
}

// - This is your test scenario
it('Load Claimed Domains ', () => {
    const { domainManagementService} = setup();
    spyOn(domainManagementService, 'getVerifiedDomains').and.returnValue(Promise.resolve([{status: 'claimed'},{status: 'claimed'}]));
    component.ngOnInit();
    expect(domainManagementService.getVerifiedDomains).toHaveBeenCalled();
    expect(component.claimedDomains.length).toBe(2);
});

但请记住正确模拟您的服务响应，以便您拥有正确的“claimedDomains”。

无法使用 jasmine 以角度测试服务方法

2 个答案: