We have it at scale, and no, it doesn't become a mess. We use Spock, which make "comments" a very expected thing, which helps us not let tests without comments

We have it at scale, and no, it doesn't become a mess. We use Spock, which make "comments" a very expected thing, which helps us not let tests without comments pass a code review. Just use a tool that helps you and stop writing stupid tests whose impl code looks worse than the code being tested.