'Piggyback' data as result from worker to main process

[nicojs]

Clear and concise description of the problem

When developing tools atop of vitest using the programmatic API, tools, like mutation testing frameworks (i.e. StrykerJS), sometimes need to report additional data from the testing environment back to the main process.

See #3017 (reply in thread)

Suggested solution

Using a custom vitest.setup.js

import { afterAll } from 'vitest';

afterAll((suite) => {
  suite.meta.custom = stuff;
});

A tool could use this:

const vitest = await createVitest("test", { watch: false });
vitest.projects[0].config.setupFiles = ["vitest.setup.js"];
await vitest.start();
vitest.state.getFiles()[0].result.meta.custom // per suite/worker we can get the custom data here

Alternative

An rpc approach is also mentioned here: #3017 (reply in thread)

Additional context

The vitest-plugin in StrykerJS currently uses files to communicate between the test environment and the main process. This works, but doesn't support "Browser mode".

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.