Documentation on how to run / filter the internal test suite

[MichalBryxi]

S far my experiments concluded that adding .only after it in the internal test suite (e.g: packages/mocha/test/acceptance/index-test.js) does not filter the tests being run via yarn test. So I just trial-and-errored on:

npx mocha packages/mocha/test/acceptance/index-test.js

• Is there a better way to run the internal test suite?
• Should that be documented somewhere?
• Shall that have an explicit term (I see "internal test suite" mentioned once in the source code)