rejectWithValue is not invoked when testing the createAsyncThunk action

[stasguma]

First of all, I understand that it's probably not right place to ask. Anyway, I hope you could help me.

I have a createAsyncThunk with a rejectWithValue that I want to test with jest.

My test file looks next. It crashed on the last line because payload is undefined and as you can see in console.log
rejectedWithValue: false.

How to make it possible to invoke rejectWithValue on a rejected status in jest?

[stasguma]

I noticed that If I change mockRejectedValue to mockResolvedValue then rejectWithValue is invoked and I get the action.payload from rejectWithValue, but the problem is that it has requestStatus: fulfilled not rejected

[phryneas]

I honestly don't know if we can help you here, this looks more like you're having problem with jest mocks.

Could I recommend that you use msw instead of mocking axios?

[stasguma]

I honestly don't know if we can help you here, this looks more like you're having problem with jest mocks.

Could I recommend that you use msw instead of mocking axios?

I'll also move the api to rtk query. Perhaps all together will help.
Thanks for reply.

[stasguma]

@phryneas Hi, I replaced axios to rtk query, jest to vitest and use MSW. I got a new problem, that not with rejectWithValue at all.
The problem is that this dispatch returns undefined and further code just breaks. MSW intercepts the call properly.

const response = await dispatch(
    sessionApi.endpoints.login.initiate({ username, password })
);

loginThunk.test.ts

loginThunk.ts

Perhaps you can provide your own vision on how to test code like this. Thank you in advance.

[phryneas]

Instead of action(dispatch, getState, undefined) maybe calling dispatch(action) might already be enough.

Test it like you would actually use it. With a real state. This mocking will get you nowhere. What guarantees that your mock actually behaves like the store?

Generally, see https://redux.js.org/usage/writing-tests - under "Example App Code" it even shows how to test a slice.