注入服务的 Angular 单元测试

Question

我不熟悉编写单元测试并试图弄清楚为组件中的注入服务编写测试。

组件：

constructor(private _assessmentService: AssessmentDataService){

}

ngOnInit(){
    const assessmentSub: Subscription = this._assessmentService.getAssessmentQuestions().subscribe(responseData => {
        const obj = responseData.assessment;
        assessmentSub.unsubscribe();
    });
}

服务：

getAssessmentQuestions(){
    return this._http.get('./assets/data/data.json').map(response => response.json());
}

模拟服务：

export const assessmentMockData = {
'assessment': [{
    'id': 1,
    'question': 'Qeustion 1',
    'options': [
        {
            'id': 1,
            'option': 'option 1',
            'score': 20
        },
        {
            'id': 2,
            'option': 'option 1',
            'score': 30
        },
        {
            'id': 3,
            'option': 'option 1',
            'score': 10
        },
        {
            'id': 4,
            'option': 'option 1',
            'score': 0
        }
    ],
    'selected': 2
}]
}

export class AssessmentMockDataService{
    getAssessment(){
        return Observable.of({});
    }
}

上述组件的规格：

beforeEach(async(() => {
TestBed.configureTestingModule({
  imports: [ReactiveFormsModule, FormsModule],
  declarations: [AssessmentComponent, QuestionsComponent],
  providers: [
    { provide: AssessmentDataService, useClass: AssessmentMockDataService }
  ]
})
.compileComponents();

  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(AssessmentComponent);
    let assessmentService: any = fixture.debugElement.injector.get(AssessmentDataService);
    spyOn(assessmentService, 'getAssessmentQuestions').and.returnValue(Observable.of(assessmentMockData));
    fixture.detectChanges();
  });

当我运行ng test -sm=false 时，我得到了错误

错误：：getAssessmentQuestions() 方法不存在

我在这里做错了什么？

Answer 1

您需要在您的模拟中添加 getAssessmentQuestions()，因为它是在您的服务的 ngInit 中调用的。

我猜你做对了，但随后将 getAssessment() 重命名为 getAssessmentQuestions() 并忘记在模拟中更改它。