We'll done! The intro paragraph says it all. We've been doing testing for years, writing it mostly in JS (as HTML replacement will clobber any existing script

We'll done! The intro paragraph says it all. We've been doing testing for years, writing it mostly in JS (as HTML replacement will clobber any existing scripted interactivity), but hate doing it because CodeMirror and other testing UIs are horrible for rapid development. This solves the need quite well, and we may find ourselves switching services as a result!