[Docs]: Difference between runner and testRunner? about jest

[SimenB]

You can look at Jest like a sort task orchestrator. Runner then is what it manages (you can use this to e.g. run ESLint via Jest). A runner is executed once for every top level invocation (or watch mode re-run).

Test runner is used by Jest's builtin runner in order to run tests. The test runner is then either jest-circus or the legacy jest-jasmine, and that's what provides describe, test, expect to tests and reports back a result.

Does that make sense? Happy to take PRs to clarify the docs

[aaronvg]

by top-level invocation, you mean when you run the Jest CLI right? I'll submit a clarification PR

[aaronvg]

Which abstraction would help me set some context right before an individual test(..) or it(..) runs? Like setting an environment variable or asynclocalstorage for the things in the test to read?

Update: Found #7774 . What i really wanted was the test name so this should work I believe. If I have any other dynamic metadata (like some uuid I want to generate per test) I'll try the custom testRunner approach.