For me, a regex usually has to be wrapped into a function, which I can then throw copious amounts of unit tests at. Regex is, IMHO, a easy-to-write hard-to-read

For me, a regex usually has to be wrapped into a function, which I can then throw copious amounts of unit tests at. Regex is, IMHO, a easy-to-write hard-to-read language, so I find it more fruitful to use tests to specify what is the task being accomplished, so that - if it's easier - I can just rewrite the appropriate regex from scratch rather than trying to decipher how the old one is broken. If the task is complex enough, regex might not even be the right tool for the job, and the function boundary provides a sensible encapsulation boundary.