Yep, very good. Perhaps even add the expected result as part of the comment.
When tdd is viable, rex can be expressed very thoroughly in tests. They need to be tested differently anyway because of their versatility, so those tests go a long way to show what it should/not do
regex101.com/ is a godsend when it comes to understanding someone else's line noise.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.