javascript-使用带延误的runSaga测试

如果我有这样的传奇故事：

function * sagaWorker() {
  yield put(START_ACTION)
  yield take(WAIT_FOR_ACTION)
  yield delay(100)
  yield put(END_ACTION)
}

我可以像这样使用runSaga成功测试它：

step('saga passes the tests', async () => {
  const channel = stdChannel()
  const dispatched = []
  const options = {
    dispatch: action => dispatched.push(action),
    getState: () => {},
    channel
  }
  const task = runSaga(options, sagaWorker)
  channel.put(WAIT_FOR_ACTION)
  await task.toPromise()
  expect(dispatched).to.deep.eql([START_ACTION, END_ACTION])
})

但是,如果我将延迟转移到汇票的前面：

function * sagaWorker() {
  yield put(START_ACTION)
  yield delay(100)
  yield take(WAIT_FOR_ACTION)
  yield put(END_ACTION)
}

现在,传奇故事并没有完成并超时-可以接受,但动作从未到达频道.

是否可以使用此表格进行测试？我怀疑我可以通过调用延迟而不是直接产生延迟来使其工作,但是我想知道如何在不这样做的情况下使其工作(如果可能的话).

解决方法:

使用yield call(()=> myPromiseyDelay(500))不会在这里保存您.派发时仍然没有什么可以注意到“丢失”的动作.

当您发布WAIT_FOR_ACTION时,由于收益延迟,传奇故事处于收益状态.这里没有行动的队列,因此,在您放弃屈服(WAIT_FOR_ACTION)时,WAIT_FOR_ACTION行动早已被分派,而您上面提出的任何佐贺逻辑都没有注意到(没有采取行动的主动行动) ).

考虑设置一个actionChannel来捕获这些未侦听的动作.延迟结束后,它们将在通道中排队等待使用.

因此,类似：

function * sagaWorker() {
  const channel = yield actionChannel(WAIT_FOR_ACTION)
  yield put(START_ACTION)
  yield delay(100)
  yield take(channel)
  yield put(END_ACTION)
}

因此,将所有内容组合为非伪代码：

const {
  runSaga,
  stdChannel,
  effects: {
    take,
    put,
    actionChannel,
    delay
  }
} = window.ReduxSaga

const WAIT_FOR_ACTION = "WAIT_FOR_ACTION";
const START_ACTION = "START_ACTION";
const END_ACTION = "END_ACTION";

(async() => {
  const channel = stdChannel();
  const dispatched = [];
  const options = {
    dispatch: action => dispatched.push(action),
    getState: () => {},
    channel
  };
  const task = runSaga(options, sagaWorker);
  channel.put({
    type: WAIT_FOR_ACTION
  });
  await task.toPromise();
  console.log(dispatched);
})();

function* sagaWorker() {
  const channel = yield actionChannel(WAIT_FOR_ACTION);
  yield put({
    type: START_ACTION
  });
  yield delay(100);
  yield take(channel);
  yield put({
    type: END_ACTION
  });
}

<script src="https://cdn.jsdelivr.net/npm/redux-saga@1.0.2/dist/redux-saga.umd.min.js"></script>

标签：redux-saga,redux,javascript
来源： https://codeday.me/bug/20191024/1922382.html