Try Vitest test runner on this repository

[HonkingGoose]

Describe the proposed change(s).

I think we want to try the Vitest test runner, to see if it's faster then Jest? I've created this issue to discuss things, and so I can link to other relevant issues.

Vitest says that: ¹

Vitest has been designed with a Jest compatible API, in order to make the migration from Jest as simple as possible. Despite those efforts, you may still run into the following differences:

Todos to migrate to Vitest

These todos come from the Vitest guide to migrate from Jest:

• Keep the globals API from Jest with the globals configuration setting or update code to use imports from the vitest module instead
• Module mocks
• Auto-mocking behavior
• Importing the original of a mocked package
• Jasmine API
• Envs
• Done Callback
• beforeAll/beforeEach hooks
• Types
• Timers (Vitest doesn't support Jest's legacy timers)
• Vue Snapshots (we probably don't use any?)

Discussion

Some things to think about:

• Vitest is not stable, the current release is v0.32.2.
• Vitest supports running consecutive tests in parallel. ²
• Supports native code coverage via v8 (default) and instrumental code coverage via istanbul ³
• Read Vitest's test runner comparison page ⁴

Related issues:

• Speed up Jest tests by using @swc/jest #20477
• Use Jest --shard option to speed up tests #14572

Is this a feature you are interested in implementing yourself?

No, I'll let somebody else test Vitest. 😉

Footnotes

1. https://vitest.dev/guide/migration.html#migrating-from-jest ↩

2. https://vitest.dev/guide/features.html#running-tests-concurrently ↩

3. https://vitest.dev/guide/coverage.html ↩

4. https://vitest.dev/guide/comparisons.html ↩

[HonkingGoose]

@zharinov sped up the tests massively. 🥳 My latest docs PR got automerged by GitHub via Merge Queue in about 10 minutes, compared to about 25 minutes before the changes. 😱

Do the maintainers still want to try Vitest, or are we happy with our current test speed?

[viceice]

yes, would like to try it.

[viceice]

i think I've not enough time to make it alone 🙃

[RahulGautamSingh]

i think I've not enough time to make it alone 🙃

I would be happy to contribute here too☺

[viceice]

not sure about the best way to start. does vitest have something like the jest.mock functions? so we can try to create some compabillity stuff?

[viceice]

https://vitest.dev/guide/migration.html
🙃