When rendering slots, it throws this error:

SyntaxError: "prefixIdentifiers" option is not supported in this build of compiler.
 - /node_modules/.vite/deps/vitest-browser-vue.js:6404:30
 - /node_modules/.vite/deps/vitest-browser-vue.js:6706:20
 - /node_modules/.vite/deps/vitest-browser-vue.js:6722:21
 - /node_modules/.vite/deps/vitest-browser-vue.js:6711:122
 - /node_modules/.vite/deps/vitest-browser-vue.js:6890:16
 - /node_modules/.vite/deps/vitest-browser-vue.js:7034:47

I am testing with this setup:

TestComponent.vue

<template>
  <div>
    <div>Hello World</div>
    <slot></slot>
  </div>
</template>

<script setup lang="ts"></script>

TestComponent.browser.test.ts

import { render } from 'vitest-browser-vue';
import TestComponent from './TestComponent.vue';

describe('TestComponent', () => {
  test('Rendering slot', () => {
    render(TestComponent, {
      slots: {
        default: 'Test',
      },
    });
  });
});

While writing this issue I finally found a way which works:

default: () => 'Test'

So I needed to transform it into a function. Is this a bug or is this supposed to work like this? If this is not a bug then there should be some instructions on your documentation how to use the slots, since the slot declarations which are written in Vue Test Utils documentation do not work.