[enw]

This always surprises me.

How come there are seemingly zero tests for what’s essentially critical infrastructure?

How do you make sure things keep working? How do you prevent regressions as team members change and tribal knowledge and intuition is lost? How do you ensure all future humans working on the project can make meaningful changes with confidence?

[oblio]

Short answer: you don't, you brute force testing with your user base and you get lucky until you don't, plus you don't care because you're too entrenched.

That's how 99% of these old timey tools work (coreutils, SSH, SSL, etc). They're getting better but you can definitely feel that they're managed by old hackers that predate CI/CD.