从redux store redux saga测试派生的模拟局部变量

Question

我已经写了一个传奇，它使用一个yield select来获取redux存储状态的一部分，并将其存储在局部变量中。该变量是一个具有三个不同键的对象，每个键的值是其中的一个对象数组。

我的redux-saga测试总是失败，因为我在saga中创建了这个使用初始yield select中的数据的本地变量，并且在测试中该变量始终为undefined，这会导致我在saga中的其余测试失败。我见过很多关于如何在redux saga中模拟yield select的返回状态的例子，但它总是在下一个redux-saga调用的上下文中。如何模拟局部变量的返回状态？

下面是我的代码：

export default function* orderSelectionFlow({ payload }) {
  try {
    const orders = yield select(getOrders); // retrieve relevant part of redux store
    const activeOrder = orders[payload.orderStatus].find(order => order.id === payload.orderId); // this variable is always undefined in my tests, because I am not sure how to mock `orders` for a local variable.
    const activeOrderId = payload.orderId;
    const isConnected = yield select(getIsConnected); // test for this select fails because activeOrder is undefined 

我的测试(直到相关的点)是

describe('test order selection flow', () => {
  const navSpy = jest.spyOn(AppNavigator, 'navigate');
  const action = {
    type: 'galactica/orders/VIEW',
    payload: {
      orderStatus: 'OPEN',
      orderId: 1
    }
  };

  afterAll(() => {
    jest.resetModules();
    navSpy.mockRestore();
  });
  it.next = sagaHelper(orderSelectionFlow(action));

  it.next('should get all orders', (result) => {
    expect(result).toEqual(select(getOrders));
  });

  it.next('should use connected state', (result) => {
    expect(result).toEqual(select(getIsConnected));
  });

Orders目前是未定义的，但如果我可以模拟它的值，它将是

orders: { 'OPEN': { orderId: 1 } }

Answer 1

我会尝试使用redux-saga-tester：https://github.com/wix/redux-saga-tester。它可以让你在选项中指定初始状态。我不太确定你的所有代码是什么样子的，但我认为你可以像下面这样做。

describe('test order selection flow', () => {
  const navSpy = jest.spyOn(AppNavigator, 'navigate');
  const action = {
    type: 'galactica/orders/VIEW',
    payload: [{
      orderStatus: 'OPEN',
      orderId: 1
    }]
  };

  afterAll(() => {
    jest.resetModules();
    navSpy.mockRestore();
  });

  it('should get all orders', (result) => {
    const tester = new SagaTester({
       initialState: {
         orders: { 
           'OPEN': { 
             orderId: 1 
           } 
         }
       }
    });

    tester.start(saga);
    tester.dispatch(action);

    // ... do your expects here
    // You may need to use `tester.waitFor` to wait for an action to be dispatched
    // If you want to expect a certain action was called, use `getCalledActions`
  });