[Bug] Can't seem to use *.stories.svelte with composeStories

[zumoshi]

Describe the bug

I was following this tutorial:
https://storybook.js.org/docs/writing-tests/snapshot-testing

But the part where I should import the stories gives me undefined:

import * as Button  from './Button.stories.svelte';
const {Primary} = composeStories(Button);

The IDE is showing errors on Button and Primary, and debugger shows Button to not have any properties for the stories.

I then tried cloning this repo separately and following:
https://github.com/storybookjs/addon-svelte-csf/blob/main/examples/StoryImporter.mdx

Just to see if I can get any reference to the stories but didn't seem able to.

Steps to reproduce the behavior

0. git clone git@github.com:storybookjs/addon-svelte-csf.git
1. run pnpm i and pnpm build
2. Create ./examples/x.spec.ts

import { expect, test } from 'vitest';
import * as ExportNameStories from './ExportName.stories.svelte';
test("x", ()=>{
  console.log(ExportNameStories);
  console.log(ExportNameStories.SimpleName);
  console.log(ExportNameStories.NameFromExportName);
})

3. Edit vitest.workspace.ts file to see the x.spec.ts file

Subject: [PATCH] x
---
/vitest.workspace.ts	(date 1762011442650)
@@ -12,6 +12,15 @@
     },
   },
   {
+    extends: './vite.config.ts',
+    test: {
+      name: 'asdasdasd',
+      dir: './examples/',
+      environment: 'happy-dom',
+      globals: true,
+    },
+  },
+  {
     extends: './vite.config.ts',
     plugins: [
       storybookTest({

5. Run the test.

I expected to see references to the Stories, but I got undefined.

Screenshots and/or logs

Environment

• OS: Linux
• Node.js version: v24.11.0
• NPM version: 11.6.1 (pnpm: 10.18.0)
• Browser (if applicable): N/A
• Browser version (if applicable): N/A
• Device (if applicable): N/A

Additional context

Cloned the repo (main branch) at e73febc

Have I misunderstood how this works, or is this a bug? How should I use stories made with this library for vitest snapshot tests?