That pops up about once a year. See https://hn.algolia.com/?query=How%20SQLite%20Is%20Tested&sor... for previous submissions.

An amazing thing about the fuzz tester American Fuzzy Lop is that even with all of the SQLite tests, it managed to find bugs. See http://lcamtuf.blogspot.se/2015/04/finding-bugs-in-sqlite-ea... , and HN comments at https://news.ycombinator.com/item?id=9376391 .