yield and takeLatest not working with jest about redux-saga HOT 8 CLOSED

Hi!

Could you please share your jest test? Thanks!

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//App-test.js

import watchCounterIncrease from '../MyAssets/Redux/saga/saga';
jest.mock('redux-saga/effects');

describe('App Screen', () => {
const result=watchCounterIncrease();
console.log(result.next().value);
console.log(result.next());
})

///Here console returning result as
console.log
undefined

  at log (__tests__/App-test.js:29:11)

console.log
  { value: undefined, done: true }

  at log (__tests__/App-test.js:30:11)

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Any suggestion?

from redux-saga.

Please always try to share a repro case in a runnable form - either by providing a git repository to clone or a codesandbox. OSS maintainers usually can't afford the time to set up the repro, even if exact steps are given.

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https://codesandbox.io/s/redux-saga-counter-example-forked-32wp08?file=/index-test.js

from redux-saga.

@komalharmale You don't want to test watchCounterIncrease because that just runs takeLatest. Saga functions -- without the redux-saga middleware -- don't activate any side-effects, they just describe the side-effects to activate.

Here's an article I wrote describing it in more detail: https://bower.sh/simplify-testing-async-io-javascript

If you want to test, when a user clicks a button and it increments the counter the user should see the number 2, then you need to write an integration test that fully sets up your redux store (with redux-saga) as well as your react/react-native app, then simulate clicks in your app, and finally test what number displays on the screen.

If you just want to test the saga increaseAsync then you should run it as a standalone generator like you were doing inside your code sandbox.

For example:

import { delay, put } from "redux-saga/effects";
import { incrementAsync } from "./sagas/index";

describe("incrementAsync", () => {
  test("should call the sampleOne function", () => {
    const iter = incrementAsync();
    expect(iter.next().value).toEqual(delay(1000));
    expect(iter.next().value).toEqual(put({ type: "INCREMENT" }));
  });
});

I hope that was helpful but feel free to continue chatting. We also have a discord for more realtime help: https://discord.gg/AKz29HvK2h

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@neurosnap Thank you for your support, but my concern is if we try to console this value then it is returning as undefined.
iter.next().value as well as delay(1000) is returning as undefined that is the reason the test cases are passing because the both value having undefined as result but in actual it's not giving as expected output.

This Redux-saga/effects not works while doing testing using Jest in React-Native.
If we Run normally like npx react-native run-android then it's work properly but when we run 'npm jest the above result in console print as undefined

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closing as issue is not related to the this library

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