Mock local variable derived from redux store redux saga testing - reactjs

Question

I have written a saga that uses a yield select to get part of the redux store state and store it in a local variable. The variable is an object with three different keys and each key's value is an array of objects within that.
My redux-saga tests keep failing because I create this local variable within the saga that uses data from the initial yield select and in the tests that variable is always undefined, which causes the rest of my tests in that saga to fail. I've seen a lot of examples about how to mock the return state of yield select in a redux saga, but it's always in the context of the next redux-saga call. How do I mock the return state for a local variable?
Here is my code:
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
My test ( up to the relevant point) is
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 is currently undefined, but if I could mock the value it would be
orders: {
'OPEN': {
orderId: 1
}
}

Answer 1

I would try using redux-saga-tester: https://github.com/wix/redux-saga-tester . It let's you specifiy the initial state in the options. I'm not quite sure what all your code looks like, but I think you could do something like below.
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`
});