您必须模拟“AngularFirestore”或按原样注入它并对其方法创建间谍,这样它就不会被调用。我不会推荐第二个选项,因为它需要注入真正的服务,这也可能依赖于其他服务。因此,您还必须注入它们,这可能最终需要数百万个服务来测试一个组件。那么,我们选择第一个选项。
如果它在您的组件中常用,我建议您为此类服务创建一个“存根”模块,并将此模块导入到您想要测试的组件测试模块中。如果只是为了这个组件,你可以创建像这样简单的东西:(让我们从简单的开始,稍后创建模块)
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
});
});
正如我之前所说,如果AngularFirestore
是许多组件使用的服务,然后在项目中的某个位置创建一个存根模块(在我的项目中我创建了一个testing
文件夹并将其放在旁边src
)
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;
}
}
现在,您不必自己提供,只需导入我们刚刚创建的模块
app.component.spec.ts
...
TestBed.configureTestingModule({
imports: [ RouterTestingModule, CommonServiceModuleStub],
declarations: [ AppComponent ]
}).compileComponents();
Option 2
有时,您的服务很简单,您不想费心去“嘲笑”它们。看看下面的例子
app.component.ts
@Component({ ... })
export class AppComponent {
constructor(private myService: AwesomeService) {}
doSomethingCool() {
this.myService.getAwesomeStuff();
}
}
让我们配置一下TestBed
first,
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();
并且在测试中
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();
});
欲了解更多信息,您可以查看茉莉花文档 https://jasmine.github.io/2.0/introduction.html#section-Spies