While I agree in general I disagree here. If you read about the Sqlite tests you will find that they do test sensibly.
One suite I'm particularly impressed with will run tests from zero bytes with slowly increasing available memory until the program passes. The tests verify that at no point the DB is corrupted by an OOM event.
Just to clarify, I wasn't criticising sqlite, I was criticising the idea of judging their code quality "for this reason alone!" - ie that they have so much test code vs implementation.
As a heuristic the code versus test-code ratio serves well as an indicator of quality. Just like consistent indentation does. You don't know whether a well-indented program is good. But if the indentation is inconsistent you'll expect worse.
One suite I'm particularly impressed with will run tests from zero bytes with slowly increasing available memory until the program passes. The tests verify that at no point the DB is corrupted by an OOM event.