测试发出延迟动作或不发出任何东西的 NGRX 效果

Question

我有一个 NGRX 效果 - 根据状态 - 发出延迟的动作或什么都不发出。我想写一个测试，涵盖这两种情况。

效果是这样的：

myEffect$ = createEffect(() =>
  this.actions$.pipe(
    ofType(MyAction),
    filter(state => state.foo === false),
    delay(4000),
    map(state => myOtherAction())
  )
);

测试应该发出延迟的otherAction工作正常：

describe('emit my action', () => {
   const action = MyAction();

   it('should return a stream with myOtherAction', () => {
      const scheduler = getTestScheduler();
      scheduler.run(helpers => {
        // build the observable with the action
        actions = hot('-a', { a: action });

        // define what is the expected outcome of the effect
        const expected = {
           b: MyOtherAction()
        };
        helpers.expectObservable(effects.myEffect$).toBe('- 4000ms b', expected);
      });
   });
});

但我不知道如何测试其他状态，它应该不发出另一个动作（流长度为零）：

   it('should return an empty stream', () => {
      store.setState({
        myFeature: {
           foo: true
        }
      });
      // ???
   });

请帮忙:)

Answer 1

这很难做到，因为过滤器会阻止效果 return 成为可观察的。

选项 1： // 无论你在哪里调度 MyAction，只有当 foo 属性在创建的 action

上为真时才调度它

选项 2： // 将效果的结构改为return空

import { EMPTY } from 'rxjs';
....
myEffect$ = createEffect(() =>
  this.actions$.pipe(
    ofType(MyAction),
    delay(4000),
    map(state => state.foo ? myOtherAction() : EMPTY)
  )
);

测试：

import { EMPTY } from 'rxjs';
....
describe('emit my action', () => {
   const action = MyAction();
   action.foo = false; // set foo property to false

   it('should return a stream with myOtherAction', () => {
      const scheduler = getTestScheduler();
      scheduler.run(helpers => {
        // build the observable with the action
        actions = hot('-a', { a: action });

        // define what is the expected outcome of the effect
        const expected = {
           b: EMPTY // assert now it is empty
        };
        helpers.expectObservable(effects.myEffect$).toBe('- 4000ms b', expected);
      });
   });
})

Answer 2

由于 AliF50 的提示，我用“Noop Action”（= 没有任何侦听器的正常操作）替换了链中的 filter（它阻止 Observable 发射）。因此，我没有检查过滤器中的 foo 属性，而是 return 地图中的 noopAction，当 foo 为真时，otherAction 为假时。

效果：

myEffect$ = createEffect(() =>
  this.actions$.pipe(
    ofType(MyAction),
    //filter(state => state.foo === false),
    delay(4000),
    map(state => state.foo !== false ? noopAction() : myOtherAction())
  )
);

测试：

describe('emit my action', () => {
  const action = MyAction();

  it('should return a stream with myOtherAction', () => {
    const scheduler = getTestScheduler();
    scheduler.run(helpers => {
      // build the observable with the action
      actions = hot('-a', { a: action });
      // define what is the expected outcome of the effect
      const expected = {
        b: MyOtherAction()
      };
      helpers.expectObservable(effects.myEffect$).toBe('- 4000ms b', expected);
    });
  });

  it('should return a stream with noop action as foo is true', () => {
    store.setState({
      myFeature: {
        foo: true
      }
    });
    const scheduler = getTestScheduler();
    scheduler.run(helpers => {
      // build the observable with the action
      actions = hot('-a', { a: action });
      // define what is the expected outcome of the effect
      const expected = {
        b: NoopAction()
      };
      helpers.expectObservable(effects.myEffect$).toBe('- 4000ms b', expected);
    });
  });

});

测试发出延迟动作或不发出任何东西的 NGRX 效果

Testing NGRX effect that emits action with delay OR does not emit anything

jasmine

ngrx-effects

jasmine-marbles

rxjs-marbles

ngrx-test