如何测试是否在 NgRX 中调度了动作？

Question

我有一个在构造函数中分派操作的组件：

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
})
export class AppComponent {    
  constructor(store: Store<State>) {
    store.dispatch(action1());
    store.dispatch(action2());
  }
}

我需要测试 action1 和 action2 是否被调度。我正在尝试使用 MockStore 来做到这一点：

import {MockStore, provideMockStore} from '@ngrx/store/testing';

let store: MockStore;

beforeEach(async () => {
  await TestBed.configureTestingModule({
    declarations: [
      AppComponent
    ],
    providers: [
      provideMockStore({ initialState }),
    ],
  }).compileComponents();
  store = TestBed.inject(MockStore);
});

这是我的测试：

it('should dispatch an action1 in constructor', () => {
  TestBed.createComponent(AppComponent);

  const expected = cold('a', {a: action1()});

  expect(store.scannedActions$).toBeObservable(expected);
});

it('should dispatch an action2 in constructor', () => {
  TestBed.createComponent(AppComponent);

  const expected = cold('a', {a: action2()});

  expect(store.scannedActions$).toBeObservable(expected);
});

这很奇怪，但只有一项测试通过了。这取决于 dispatch() 调用的顺序。

store.scannedActions$ 只包含一个值。如果组件代码是：

constructor(store: Store<State>) {
  store.dispatch(action1());
  store.dispatch(action2());
}

那么 store.scannedActions$ 只包含 action2()

如果组件代码是：

constructor(store: Store<State>) {
  store.dispatch(action2());
  store.dispatch(action1());
}

那么 store.scannedActions$ 只包含 action1()

如何测试这两个动作？

Answer 1

看起来 scannedActions$ 尽管它是复数（动作），但只存储了最后一个调度的动作，查看它的 interface。

我只会使用 spyOn 并监视 store.dispatch 并查看是否使用正确的操作调用它。

import {MockStore, provideMockStore} from '@ngrx/store/testing';

let store: MockStore;

beforeEach(async () => {
  await TestBed.configureTestingModule({
    declarations: [
      AppComponent
    ],
    providers: [
      provideMockStore({ initialState }),
    ],
  }).compileComponents();
  store = TestBed.inject(MockStore);
});

it('should dispatch action1 and action 2 in constructor', () => {
  const dispatchSpy = spyOn(store, 'dispatch').and.callThrough(); // spy on the store 
  // dispatch but still call the actual implementation
  TestBed.createComponent(AppComponent);
  fixture.detectChanges(); // used to call ngOnInit, maybe it is not needed

  expect(dispatchSpy).toHaveBeenCalledWith(action1());
  expect(dispatchSpy).toHaveBeenCalledWith(action2());
});

如何测试是否在 NgRX 中调度了动作？

How to test if action is dispatched in NgRX?

angular

karma-jasmine

ngrx

ngrx-store