Cant get setup({server: true}) to work

[VirgileD]

Describe the bug

I try to test an endpoint of my sveltekit app that is redirecting a request to another domain. it goes like this:

import { redirect } from '@sveltejs/kit';

/** @type {import('@sveltejs/kit').Handle} */
export async function handle({ event, resolve }) {
    const url = new URL(event.request.url);
    url.host = 'toto.li';
    url.port = '';
    url.protocol = 'https';
    console.log(`Redirecting to: ${url}`)
    throw redirect(301, url);
}

My vitest is the following:

import { describe, it, expect, afterAll, beforeAll } from 'vitest';
import { setupServer } from 'msw/node'
import { rest } from 'msw'
import { setup } from 'vite-test-utils';
import fetch from 'node-fetch';

const mswServer = setupServer(
  // catch the redirect and return the user agent of the request
  rest.get('https://toto.li/123', (req, res, ctx) => {
    return res(ctx.status(200), ctx.json({ id: req.headers.get('user-agent') }))
  })
)

beforeAll(async () => {
    mswServer.listen({ onUnhandledRequest: 'bypass' })
});

afterAll(() => mswServer.close())

describe('Test redirections', async () => {
    await setup({ server: true }); // launch the application

    it('should redirect directly when not request by a browser', async () => {
        // request any endpoint, this will be handled in the hooks.server.js handler of sveltekit
        const response = await fetch('http://localhost:3000/123', {
            headers: {
                'user-agent': 'whatever but not mozilla'
            }
        })
        expect(response.status).toBe(200)
        const data = await response.json()
        // the msw mock for toto.li is returning the user-agent
        expect(data.id).toBe('whatever but not mozilla')
    })
});

With this, it seems that the mswServer mockup is failing to catch the request to toto.li that is executed in hooks.server.js.

If I remove the await setup({ server: true }) and manually launch the sveltekit app using npm run dev, everything is working fine.

Maybe it's a problem with msw but I thought I'd ask here first. What do you think?

Reproduction

see the description

System Info

System:
    OS: Linux 5.10 Ubuntu 20.04.6 LTS (Focal Fossa)
    CPU: (8) x64 Intel(R) Core(TM) i7-10610U CPU @ 1.80GHz
    Memory: 22.24 GB / 24.74 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Node: 18.17.1 - ~/.nvm/versions/node/v18.17.1/bin/node
    Yarn: 1.22.19 - /usr/bin/yarn
    npm: 10.1.0 - ~/.nvm/versions/node/v18.17.1/bin/npm

Used Package Manager

npm

Additional context

No response

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• [X] The provided reproduction is a minimal reproducible of the bug.