I did a little song-and-dance that sets up Puppeteer* , takes screenshots of your app (like, all the routes you care about), and then compares them to the “golden” ones. If they match, your test passes! Yes, it only works on Chrome. No, it’s not actually unit testing. Yes, it’s literally just counting pixels but you know what? It counts them in both a wide and a narrow viewport size and any testing is better than no testing at all; fight me.
Uptime and SSL certificate monitoring doesn't have to be boring, confusing or expensive. Together with my buddy Mattias Geniar I'm currently building Oh Dear: a webapp to keep an eye on the health of your websites. Register here to try it out. (sponsored link)