A ghost hand and an audience of one

ℹ️ TL;DR I taught my software test suite to record training videos. They star the real application, they narrate themselves with captions, and when the app changes, I rebuild them with one command instead of re-filming anything. The system was invented in an evening to teach one person her own custom software; the next night it made a forty-nine-video library for LocallyGrown.net. This is the story; a companion post has the technical details. Modern software developers write automated tests for their applications that use the app the way a person does. The tests open a browser, sign in, tap the buttons, fill in the forms, and check that the right things happened. Normally all of this runs invisibly, in what’s called a headless browser, which is exactly what it sounds like: a browser with no window, doing its work where nobody can see. You just get a list of green checkmarks at the end. Earlier this week I gave the tests for one of my projects a visible mode, mostly out of curiosity,…