Feat/vitest

[odinvanderlinden]

Todo:

• implement test filter for mutantRun in vitest-test-runner.ts with regex filter
• more unit tests if possible
• more integration tests
• add 1 e2e test
• refactor vitest-test-runner.ts
• Enable Stryker on integration tests
• Unit test the FileCommunicator
• Remove other changes.
• Support workspaces, see Regression in 0.30.0: changing config after createVitest no longer supported vitest-dev/vitest#3365 and Feat/vitest #4043 (comment)
• Clean state after each run, see Accesing vitest Globals vitest-dev/vitest#3017 (comment)

Optional:

• Add option to change config file path

[nicojs]

We didn't think of a huge oversight, see the comment.

[nicojs]

As of vitest@0.30.0, vitest supports workspaces. This has 2 consequences:

1. We cannot use the vitest.config anymore to set setupFiles. They now need to be set for each project in the workspace.
2. The afterAll hook we use to write stuff to the communication dir is now being called once for each workspace. We should I think collect data inside a dir, instead of a file.

[nicojs]

I've discovered another issue with vitest. See vitest-dev/vitest#3403. This is a show-stopper for us. 😢

[nicojs]

I think I managed to fix all issues.

This is a list of all the workarounds/changes I've applied since @odinvanderlinden's first draft

• Since v0.30.0 vitest supports workspaces. This had a breaking change in the programmable API. Instead of using vitest.config we now use vitest.projects.forEach(project => project.config). See Regression in 0.30.0: changing config after createVitest no longer supported vitest-dev/vitest#3365
• Our vitest.setup.js file is now inlined using deps.inline, because otherwise they are cached by nodejs. See Hooks not working when loaded from an external vitest.setup.js file vitest-dev/vitest#3403
• When inlined, the vitest.setup.js file is cached between runs, because we're not using --watch mode. So we manually bust the cache for it using vitest.projects[0].server.moduleGraph.invalidateModule, see Setup files are cached between runs vitest-dev/vitest#3409

@steschi, thanks for your reaction, but we should be able to get this working 😅

[steschi]

@nicojs sorry, didn't wanna confuse anybody with my reaction but I can relate to some of the burden of making things work with vite from my workplace.

Generally really excited to see this landing eventually, finally getting to have proper mutation testing on a modern web application stack 😍. Did not think I'd be able to apply some of the principles thought at university within a very modern web ecosystem like vite and vitest.

Thanks for the work you and your team is doing on this and greetings from Austria! 👋🏻