The bit on test coverage is particularly good: https://corecursive.com/066-sqlite-with-richard-hipp/#testin... :

Let’s not dwell on the details, but I had this idea, I’m going to write tests to bring SQLite up to the quality of 100% MCDC, and that took a year of 60 hour weeks. That was hard, hard work. I was putting in 12 hour days every single day. I was just getting so tired of this because with this sort of thing, it’s the old joke of, you get 95% of the functionality with the first 95% of your budget, and the last 5% on the second 95% of your budget. It’s kind of the same thing. It’s pretty easy to get up to 90 or 95% test coverage. Getting that last 5% is really, really hard and it took about a year for me to get there, but once we got to that point, we stopped getting bug reports from Android.