Describe the problem

Hello,

I’ve been trying to follow the new Storybook 9.0.12 documentation that includes support for Vitest 3.2. Specifically, I used the example from this page, using the new projects filed from vitest 3.2:

https://storybook.js.org/docs/writing-tests/integrations/vitest-addon#example-configuration-files

However, when I run npm run test, I get the following error:

Error: Failed to import test file /home/.../.storybook/vitest.setup.ts  
Caused by: TypeError: Failed to fetch dynamically imported module: http://localhost:63315/home/..../.storybook/vitest.setup.ts?import&browserv=1750269175644

The path was correct.

I tried a clean install and noticed that the generated vitest.config.ts differs from the one shown in the documentation. In particular, the working version includes:

// inside project config
extends: true,

Adding this field resolved the issue.

To help others avoid this problem, I opened a pull request to update the documentation accordingly:
#31814

Let me know if anything else is needed. Thanks!

Additional context

No response