[BUG] - @testdeck/vitest is relying on commonjs module

[Lukinoh]

Testdeck Version

0.3.0

Testdeck Package

• @testdeck/vite

NodeJS Version

• 18

Mocha / Jasmine / Jest / Vitest Version

• Vitest: 0.24.5

Operating System

• Other: WSL2

Actual Behaviour

I tried to use @testdeck/vitest on a small project, but it does not work because the build provided by testdeck is using commonjs, and vitest is not compatible with commonjs.

You can reproduce the issue easily on your repository by using the build output in your tests :

cd packages/vitest
sed -i 's/\.\/index/\.\/dist\/index.js/g' test.ts
npm run test

If you modify the tsconfig.json by

• Removing "module": "commonjs"
• Adding "moduleResolution": "node"

It will work, in your tests.

Expected Behaviour

It should not rely on commonjs, otherwise, it won't work natively with vitest.

[silkentrance]

@Lukinoh Thank you very much for the quick feedback.

I have to look into this as testdeck is meant for being used in both the browser and node.

[silkentrance]

@Lukinoh Which version of vitest are you using? Looking at vitest-dev/vitest#325 it seems as if this was already fixed.

[Lukinoh]

I made a typo in my ticket.
0.24.5 was the version of vitest not vite. I will change that.

You can find my small project with the bug here: https://stackblitz.com/edit/vitejs-vite-rqocxq?file=package.json

But concretely what seems to happen is that "@testdeck/vitest" loads the file index.cjs of vite which is empty.

[silkentrance]

I have looked into this.

Importing from ESM into CJS modules is quite tricky and requires a top level await, i.e.

const { expect } = await import("vitest");

While this works after the fact, i.e. the dist/index.js file is patched, it will not work when transpiling with tsc, as it requires esnext as its target and esnext for the module type. In addition it requires moduleResolution set to node.

[silkentrance]

Importing from CJS into ESM seems to be working, though.

So maybe just making @testdeck/vitest an ESM would do the trick while we figure out on how to deal with the other packages and their ESM support. (mocha >= 9, jasmine ?, jest ?, di-typedi ?)

[Lukinoh]

As vitest is thought to be ESM first, it would make sense to me.