> And remember, nothing was broken in a way that a machine would notice, so automated acceptance tests wouldn't have caught this regression.

I'd like to nit here that visual regression test harnesses for web application development do exist. [1] [2] [3] Using something like Sauce Labs you could conceptually have these tests run on Windows machines in the cloud.

However, having implemented visual regression testing in the past in various projects, I can personally vouch that it's a huge waste of time. Your tools will break all the time, your tests will break all the time, and you'll generally have a bad time.

[1] https://github.com/chenglou/node-huxley [2] https://github.com/Huddle/PhantomCSS [3] https://github.com/bradgignac/janus