Overriding msw mock handler does not work when using nuxt environment.

[segamiken]

Detail

When using nuxt/test-utils together with msw, even if I override the handler using server.use in the test file, for some reason the data from the default handler is still being rendered.

There are some related issues on the nuxt/test-utils side as well, but does anyone have any idea what might be causing this?

nuxt/test-utils#1222

Reproduction repository

This test doesn't pass.

import { describe, it } from 'vitest';
import { screen, render } from '@testing-library/vue';
import TodoList from '../TodoList.vue';
import { server } from '~/vitest.setup';
import { http, HttpResponse } from 'msw';

describe('TodoList', () => {
  it('should render todos', async () => {
    server.use(
      http.get('https://localhost:3000/todos', () => {
        return HttpResponse.json([
          { id: 1, title: 'Todo 3' },
        ]);
      }),
    );

    render(TodoList);
    await screen.findByText('Todo 3');
  });
});

https://github.com/AlexanderForm1/nuxt-msw-override

Reproduction steps

1. clone repository
2. run npm install
3. run npx vitest

[kettanaito]

Hi, @segamiken. Is that override handler being hit at all?

When something doesn't get mocked as expected, always follow the Debugging runbook. Please do that and share with me what you find.

[segamiken]

@kettanaito

Thank you for your help!

As a premise, the mock handler override works fine when using @testing-library/vue, but it doesn't work when using nuxt-test-utils.
You can reproduce this behavior with the following repository:
https://github.com/AlexanderForm1/nuxt-msw-override

I went through the Debugging Runbook and performed the necessary steps, but both environments seem to be set up correctly. The root cause is still unclear...

Here are the results of my debugging:

step-1-verify-setup

@testing-library/vue & happy-dom	@nuxt/test-utils & happy-dom

step-2-verify-handler

@testing-library/vue & happy-dom	@nuxt/test-utils & happy-dom

[segamiken]

@kettanaito
Would you happen to know anything about this issue?