For two years our telehealth product tested video calls the same way: before a release, two people on the QA team joined a call from different rooms and said "I can see you". Regressions in codec negotiation, reconnection and screen sharing reached customers anyway, because the manual check covered one network, two browsers and about ninety seconds of call time. We now run more than forty automated call scenarios on every merge. This post covers the parts that made it work: fake media...