Vuetify 3, vue/test-utils : Layout error, when mounting a vuetify component in a unit test file

I'm using VITE & VITEST for my VUE3 project and also Vuetify. Recently I tried to setup VITEST so that I could perform some component testing. To do that I used the library vue/test-utils as well as its mount() method. I have successfully written some tests for some components I made. But when I try to mount my Header component which use a v-app-bar from Vuetify, it displays the following error message:

Error: [Vuetify] Could not find injected layout

[Vue warn]: injection "Symbol(vuetify:layout)" not found.

I used the shallow: true property of the mount() method just to check on the DOM generated :

import { mount } from '@vue/test-utils';
import DefaultHeader from './DefaultHeader.vue';

// Mocking routes to pass these data as props
const routes = [
{
    path: '/',
    name: 'Home',
    meta: {
        header: false,
    },
},
{
    path: '/example1',
    name: 'Example1',
    meta: {
        header: true,
    },
    children: [
        {
            path: 'one',
            name: 'One',
        },
        {
            path: 'two',
            name: 'Two',
        },
    ],
},
{
    path: '/example2',
    name: 'Example2',
    meta: {
        header: true,
    },
}];
// stubs is for not mounting Login, Logout, UserMenu components as
// they are supposed to be tested independently
const stubs =  {
    UserMenu: {
        template: '<span />',
    },
    AppLogo: {
        template: '<span />',
    },
    Login: {
        template: '<span />',
    }
};

test('Properly displays the headers of a route list', async () => {
    const header = mount(DefaultHeader, {
        props : { routes },
        global: {
            stubs
        },
        attachTo: document.getElementById('app')
    });
    /* routes.forEach(route => {
        expect(document.getElementById('app')).toBe(1);
    }); */
});

Here is my header component :

<script setup>
import AppLogo from '@/components/AppLogo.vue';
import UserMenu from '@/components/menus/UserMenu.vue';
import Login from '@/components/Login.vue';

const props = defineProps({
  routes: {
    type: Array,
  }
});

</script>

<template>
  <v-app-bar
    name="app-bar"
    color="blue-grey"
    flat
    hide-on-scroll
  >
    <v-btn to="/">
      <AppLogo />
    </v-btn>

    <v-btn
      class="text-white"
      v-for="route in routes"
      :key="route"
      :to="route.path"
    >
      {{ route.name }}
    </v-btn>

    <v-spacer/>

    <Login />

    <UserMenu />
  </v-app-bar>
</template>

I also run a setup.js script before each test file :

import { install } from 'resize-observer';
import { config } from '@vue/test-utils'
import vuetify from '../plugins/vuetify';
import { enableAutoUnmount } from '@vue/test-utils';
import { afterEach } from 'vitest';

enableAutoUnmount(afterEach)

config.global = {
  plugins: [vuetify],
}

/* With jest-dom the resizeObserver seems to not be included, it is used by Vuetify so we have
   to include it somehow for tests.
*/
if (!window.ResizeObserver) install();

// // Custom container to integrate Vuetify.
// // Vuetify requires you to wrap your app with a v-app component that provides
// // a <div data-app="true"> node.
const app = document.createElement('div');
app.setAttribute('data-app', 'true')
app.setAttribute('id', 'app')
document.body.appendChild(app);

Here is the vuetify.js file used in the setup :

/**
 * plugins/vuetify.js
 *
 * Framework documentation: https://vuetifyjs.com`
 */

// Styles
import '@mdi/font/css/materialdesignicons.css'
import 'vuetify/styles'

// Composables
import { createVuetify } from 'vuetify'
import * as components from 'vuetify/components'
import * as directives from 'vuetify/directives'

// https://vuetifyjs.com/en/introduction/why-vuetify/#feature-guides
export default createVuetify({
  components,
  directives,
  theme: {
    themes: {
      light: {
        colors: {
          primary: '#1867C0',
          secondary: '#5CBBF6',
        },
      },
    },
  },
})

And finally here is my vite.config.js in which I also did the VITEST config (see the test property), even if I don't think I did an error during the config since it works perfectly for other components that don't use the layouts from Vuetify.

/// <reference types="vitest" />

// Plugins
import vue from '@vitejs/plugin-vue'
import vuetify, { transformAssetUrls } from 'vite-plugin-vuetify'

// Utilities
import { defineConfig } from 'vite'
import { fileURLToPath, URL } from 'node:url'

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [
    vue({ 
      template: { transformAssetUrls }
    }),
    // https://github.com/vuetifyjs/vuetify-loader/tree/next/packages/vite-plugin
    vuetify({
      autoImport: true,
      styles: {
        configFile: 'src/styles/settings.scss',
      },
    }),
  ],
  define: { 'process.env': {}},
  resolve: {
    alias: {
      '@': fileURLToPath(new URL('./src', import.meta.url))
    },
    extensions: [
      '.js',
      '.json',
      '.jsx',
      '.mjs',
      '.ts',
      '.tsx',
      '.vue',
      '.scss'
    ],
  },
  server: {
    host: "<server host>",
    port: "<server port>",
  },
  test: {
    // https://vitest.dev/guide/#configuring-vitest
    globals: true,
    environment: 'jsdom',
    deps: {
      inline: ['vuetify'],
    },
    setupFiles: './src/tests/setup.js',
  },
})

I can't find the root of the problem, when I run my app I don't get any error or warning referencing this error. Also I still don't understand what this warning in the Vuetify doc means : Vuetify layout warning which could be the cause of the error I get.

I succeeded with the use of a custom component VuetifyWrapper that is just a v-app with a slot in it, then I use the following workaround :

import VuetifyWrapper from '../tests/VuetifyWrapper.vue';
import { h } from 'vue';

...

test('Properly displays the headers of a route list', async () => {
    /* When using v-layouts the component won't load for an unknow reason,
       we have to mount the component inside a V-APP, so we use this workaround.
    */
    const wrapper = mount(VuetifyWrapper, {
        slots: {
            default: h(DefaultHeader, {
                routes,
            }),
        },
        global: {
            stubs,
        },
    });
});

I'm not quite satisfied, Vuetify 3 isn't in beta anymore so I'd like to find a cleaner way of making this work.