Agile Thoughts uses music to illustrate how test automation and Continuous Integration works: https://agilenoir.biz/en/agilethoughts/test-automation-pyramid-series/
Just out of curiosity: Why is this seeming self-promotion without a question in ask hn?
Text-only posts generally pop up under Ask HN. The Ask HN prefix is a custom, not a requirement, for showing up here. The submitter knows how to submit links correctly (check their history) but chose this option for whatever reason.
Macro tests, micro tests, subcutaneous tests. And CI.