> What Facebook needs to do is to test whether their changes don't break other people's apps. I'd argue this is at the very core of why you test. I mean this p

> What Facebook needs to do is to test whether their changes don't break other people's apps. I'd argue this is at the very core of why you test. I mean this problem is as simple as (n+1).m vs n.(m+1) in terms of versioning vs revisioning. If that is not being tested then I'd say Facebook isn't actually testing at all - at least not in a practically relevant sense ... ... despite the shit-load of YouTube videos from FB devs lecturing about CI/CD and what not.