RFT (request for tests) on variable length lookbehind branch

The branch at

https://perl5.git.perl.org/perl.git/shortlog/refs/heads/smoke-me/khw-vlb

contains a preliminary implementation of variable length look behind.

I'm looking for people to cook up tests for it, as my imagination seems 
to be limited here.

• RFT (request for tests) on variable length lookbehind branch by Karl Williamson
• Re: RFT (request for tests) on variable length lookbehind branch by James E Keenan
• Re: RFT (request for tests) on variable length lookbehind branch by Karl Williamson