如何使用 runSaga / redux-saga 接收拍摄

Question

我创建了一个 recordSaga 函数，它的目标是记录在 saga 期间调度了哪些动作。

export const recordSaga = async (saga, initialAction, state) => {
  const dispatched = [];

  const done = await runSaga(
    {
      dispatch: action => dispatched.push(action),
      getState: () => state,
    },
    saga,
    initialAction,
  ).done;

  return {
    dispatched,
    done,
  };
};

假设我的传奇是这个

export function* mySaga() {
  const needToSave = yield select(needToSaveDocument);
  if (needToSave) {
    yield put(saveDocument());
    yield take(SAVE_DOCUMENT_SUCCESS);
  }
  yield put(doSomethingElse())
}

我想写两个测试，我希望是下面的

describe('mySaga', async () => {
  it('test 1: no need to save', async () => {    
    const state = { needToSave: false }
    const { dispatched } = await recordSaga(mySaga, {}, state);
    expect(dispatched).toEqual([
      doSomethingElse()
    ])
  })
  it('test 2: need to save', async () => {
    const state = { needToSave: true }
    const { dispatched } = await recordSaga(mySaga, {}, state);
    expect(dispatched).toEqual([
      saveDocument(),
      doSomethingElse()
    ])
  })
})

但是，对于测试 2，中间有一个 take，当然还有 jest（或其女友 jasmine）对我大喊大叫：Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL.

我知道这是因为 runSaga 正在等待 take(SAVE_DOCUMENT_SUCCESS)，但我该如何模拟呢？

Answer 1

答案stdChannel().put({type, payload})

为什么？

使用stdChannel，您可以在第一次运行后调度。

如何？

• 导入标准频道；
• 添加到 runSaga 中的第一个参数；
• 致电stdChannel().put(SAVE_DOCUMENT_SUCCESS)；

示例

什么对我有用

我离开了第一个测试，因为它是预期的最终结果，但解决方案出现在最后 2 个。

  import { runSaga, stdchannel } from 'redux-saga'
  let dispatchedActions = [];
  let channel;
  let fakeStore;

  beforeEach(() => {
    channel = stdChannel(); // you have to declare the channel to have access to it later
    fakeStore = {
      channel, // add it to the store in runSaga
      getState: () => "initial",
      dispatch: (action) => dispatchedActions.push(action),
    };
  });

  afterEach(() => {
    global.fetch.mockClear();
  });

 it("executes getData correctly", async () => {
    await runSaga(fakeStore, getData, getAsyncData("test")).toPromise();
    expect(global.fetch.mock.calls.length).toEqual(1);
    expect(dispatchedActions[0]).toEqual(setData(set_value));
  });

  it("triggers takeLatest and call getData(), but unfortunately doesn't resolve promise", async () => {
    await runSaga(fakeStore, rootSaga)// .toPromise() cannot be used here, as will throw Timeout error
    channel.put(getAsyncData("test")); // if remove this line, the next 2 expects() will fail
    expect(global.fetch.mock.calls.length).toEqual(1);
    // expect(dispatchedActions[1]).toEqual(setData(set_value)); // will fail here, but pass on the next it()
  });

  it("takes the promised data from test above", () => {
    expect(dispatchedActions[1]).toEqual(setData(set_value));
  });

this answer (about true code, not tests) helped me

Answer 2

通过查看recordSaga：

export const recordSaga = async (saga, initialAction, state) => {

您似乎应该将{type: SAVE_DOCUMENT_SUCCESS} 作为第二个参数传递（即initialAction）。这应该会触发take 效果。