[英]How to provide/mock Angularfirestore module inside angular component for default test to pass?
如何在app.component中提供AngularFirestore模塊,以便我的默認toBeTruthy()
測試將通過?
Error: StaticInjectorError(DynamicTestModule)[AppComponent -> AngularFirestore]:
StaticInjectorError(Platform: core)[AppComponent -> AngularFirestore]:
NullInjectorError: No provider for AngularFirestore!
app.component
export class AppComponent implements OnInit {
private notesCollection: AngularFirestoreCollection<any>;
public notes: Observable<any[]>;
constructor(private afs: AngularFirestore) {}
ngOnInit() {
this.notesCollection = this.afs.collection('notes');
this.notes = this.notesCollection.valueChanges();
}
}
這只是默認測試:
class FirebaseMock implements AngularFirestore {
app: FirebaseApp;
firestore: FirebaseFirestore;
persistenceEnabled$: Observable<boolean>;
collection<T>(path: string, queryFn?: QueryFn): AngularFirestoreCollection<T> {
return undefined;
}
doc<T>(path: string): AngularFirestoreDocument<T> {
return undefined;
}
createId(): string {
return undefined;
}
}
describe('AppComponent', () => {
let component: AppComponent;
let fixture: ComponentFixture<AppComponent>;
beforeEach(
async(() => {
TestBed.configureTestingModule({
imports: [
RouterTestingModule,
],
declarations: [ AppComponent ],
providers: [
{
provide: AngularFirestoreModule,
useClass: FirebaseMock
},
],
}).compileComponents();
}),
);
beforeEach(() => {
fixture = TestBed.createComponent(AppComponent);
component = fixture.componentInstance;
fixture.detectChanges();
});
it('should create', () => {
expect(component).toBeTruthy();
});
});
您必須模擬“AngularFirestore”或按原樣注入它並在其方法上創建間諜,以便不會被調用。 我不建議使用第二個選項,因為它需要注入實際服務,這也可能取決於其他服務。 因此,您必須注入它們,這可能最終需要數百萬個服務才能測試一個組件。 那么,讓我們選擇第一個選項。
如果它在您的組件中常用,我建議您為這些類型的服務創建“存根”模塊,並將此模塊導入您要測試的組件測試模塊中。 如果它只是用於這個組件,你可以像這樣簡單地創建:(讓我們從簡單的開始,稍后創建模塊)
app.component.spec.ts
describe('AppComponent', () => {
let component: AppComponent;
let fixture: ComponentFixture<AppComponent>;
const AngularFirestoreStub = {
// I just mocked the function you need, if there are more, you can add them here.
collection: (someString) => {
// return mocked collection here
}
};
beforeEach(
async(() => {
TestBed.configureTestingModule({
imports: [ RouterTestingModule],
// I used 'useValue' because it is just a json. If it was class, I'd use 'useClass'
providers: [{provide: AngularFirestore, useValue: AngularFirestoreStub}]
declarations: [ AppComponent ]
}).compileComponents();
})
);
beforeEach(() => {
fixture = TestBed.createComponent(AppComponent); // Should be fine
component = fixture.componentInstance;
fixture.detectChanges();
});
it('should create', () => {
expect(component).toBeTruthy(); // Should pass
});
});
正如我之前所說,如果AngularFirestore
是許多組件使用的服務,那么在項目的某個地方創建一個存根模塊(在我的項目中,我創建了一個testing
文件夾並將其放在src
旁邊)
CommonServiceModuleStub
@NgModule({
providers: [{provide: AngularFirestore, useClass: AngularFirestoreStub}]
})
export class CommonServiceModuleStub {}
// I'd recommend you put this service in a subfolder.
// This time, I created a class instead of a json.
// It is because, your other components may require more 'mocked' functions.
// It may be harder to maintain them within a json.
@Injectable()
export class AngularFirestoreStub {
collection(someString) {
// return mock collection;
}
}
現在,而不是自己導入我們剛創建的模塊
app.component.spec.ts
...
TestBed.configureTestingModule({
imports: [ RouterTestingModule, CommonServiceModuleStub],
declarations: [ AppComponent ]
}).compileComponents();
選項2
有時,您的服務很簡單,您不想費心去“嘲笑”它們。 看一下下面的例子
app.component.ts
@Component({ ... })
export class AppComponent {
constructor(private myService: AwesomeService) {}
doSomethingCool() {
this.myService.getAwesomeStuff();
}
}
我們先配置TestBed
,
app.component.spec.ts
...
TestBed.configureTestingModule({
imports: [ RouterTestingModule],
// since, 'AwesomeService' is a service on its own and
// doesn't require other services, we easily provide it here
providers: [ AwesomeService ]
declarations: [ AppComponent ]
}).compileComponents();
並且在測試中
it('should do something cool without getting awesome stuff', () => {
spyOn(component.myService, 'getAwesomeStuff');
// Note: if you want to spy on it and you want it to get called for real
// you should do following
// spyOn(component.myService, 'getAwesomeStuff').and.callThrough();
// or return fake output
// spyOn(component.myService, 'getAwesomeStuff')
// .and.callFake((arguments, can, be, received) => {
// return fake;
// });
component.doSomethingCool();
expect(component.myService.getAwesomeStuff).toHaveBeenCalled();
});
有關更多信息,您可以查看jasmine文檔
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