BDD - Regular expression Generators / Evaluators
If you are using BDD and creating step definitions you surely are using a lot of regex, whatever is your reason to create regex there is no one solution that helps you generate them.
What we should realize is that there can't be a perfect regex generator but you definitely can make use of software that helps you create them.
The closest tool that generates a regex is http://regex.inginf.units.it/\\
It uses a template-based, modularized and very generalized approach to regular expression generation. The expressions it generates works, but they are much more complex than the equivalent hand-crafted expression. Please look at the video tutorial here.
The best tools that help you create your own regular expressions are:
Happy Regexing :P