Van Halen had a famous policy to test whether a venue paid attention to details. In the snacks section of their contract, they had clearly stated: WARNING: NO BROWN M&Ms. It was a very clever way of determining if the producer paid attention to details.
In my current DevOps role, my PyTest suites are my "No Brown M&Ms" indicator. If can run the tests and they all perform some reasonable assertions that succeed, I'll trust the developer. If I get poorly written tests or no tests at all, I get suspicious of the code quality and will dig deeper, or better yet, kick it back as "unacceptable."