Angular 单元测试 - 如何从注入的服务触发另一个发射？

如何解决Angular 单元测试 - 如何从注入的服务触发另一个发射？

我有一个执行以下操作的组件：

1. 在构造函数中，它接受查询参数并将它们解析为给定的季度和年份

2. 在 ngOnInit 中，它订阅了一个返回季度和年份列表的服务。在订阅的回调中，它使用季度和年份的值为从查询参数中选择的季度和年份分配一个值，如果它们无效，则为列表中的第一个分配一个值。

在我的单元测试中，我能够设置参数（或至少是快照），但我想重新触发 subscribe 方法内的回调并断言一些期望。我不确定如何在订阅方法中重新触发回调。

这是我的组件的相关代码：

@Component({
    ...
})
export class MyComponent implements OnInit {
quarter: number;
year: number;
paramQuarter: string;
selectedQuarter: IQuarter;
quartersList: IQuarter[];

constructor(
            private quarterService: QuarterService,private activatedRoute: ActivatedRoute,private router : Router) {

    // if no query param is set,set as the current quarter and year from moment.js
    this.paramQuarter = this.activatedRoute.snapshot.queryParams['quarter'] 
        || moment().quarter() + '-' + moment().year();

}

ngOnInit(): void {

    this.quarterService.getQuarters().subscribe(response => {
        this.quartersList = response;
        /// ----------------------------------
        /// The code I want to test is in here
        /// ----------------------------------
        const [quarter,year] = this.paramQuarter.split("-").map(string => parseInt(string));
        // get the correct quarter based on URL params,or the current one if the url param is malformed
        this.selectedQuarter: IQuarter = this.quartersList
            .filter(q => q.quarter === quarter && q.year === year)[0]
            || this.quartersList[0];
    });
}

}

以及测试：

const MOCK_QUARTERS = [
{
    quarter: 2,year: 2020,startDate: '2020-04-01',endDate: '2020-06-30',},{
    quarter: 1,startDate: '2020-01-01',endDate: '2020-03-31',}
]

describe('MyComponent',() => {
let component: MyComponent;
let fixture: ComponentFixture<MyComponent>;
let quarterService: QuarterService;
let router : Router;
let activatedRoute : ActivatedRoute;

const MockQuarterService = {
    getQuarters: jasmine.createSpy('getQuarters').and.returnValue(
    of(MOCK_QUARTERS)
    )
}

beforeEach(async(() => {
    Testbed.configureTestingModule({
    declarations: [
        MyComponent,],imports: [
        SharedModule,RouterTestingModule,...HttpClientTestingImports,providers: [
        ...HttpClientTestingProviders,{ provide: QuarterService,useValue: MockQuarterService },{
        provide: ActivatedRoute,useValue: {
            queryParams: of({ quarter: '2-2020' }),snapshot: {
            queryParams: { quarter: '2-2020' }
            }
        }
        },]
    })
    .compileComponents();
}));

beforeEach(() => {
    fixture = Testbed.createComponent(MyComponent);
    component = fixture.componentInstance;
    quarterService = Testbed.inject(QuarterService);
    router = Testbed.inject(Router);
    activatedRoute = Testbed.inject(ActivatedRoute);
    fixture.detectChanges();
});

fit('should set the current quarter from correctly formed URL params',async(() => {
    // set from the params in the beforeEach callback
    expect(component.selectedQuarter).toEqual(MOCK_QUARTERS[0]);
    spyOn(component,'updateQuarterSelection').and.callThrough();

    let actRoute : ActivatedRoute = fixture.debugElement.injector.get(ActivatedRoute);
    actRoute.queryParams = of( {quarter: `${MOCK_QUARTERS[1].quarter}-${MOCK_QUARTERS[1].year}` } );
    actRoute.snapshot.queryParams.quarter = `${MOCK_QUARTERS[1].quarter}-${MOCK_QUARTERS[1].year}`;
    /// ----------------------------------
    // Somehow need the callback of the quarterService.getQuarters().subscribe() 
    // method to retrigger here
    /// ----------------------------------
    fixture.detectChanges();
    console.log(component);
    
    expect(quarterService.getQuarters).toHaveBeenCalledTimes(2);
    expect(component.updateQuarterSelection).toHaveBeenCalledTimes(2);
    expect(component.selectedQuarter).toEqual(MOCK_QUARTERS[1]);
}));

});