Interesting, just last week I was conjecturing over rust red. That's based off my project Erlang-Red.
Of interest to you might be the visual test cases I put together to ensure that Erlang-Red works and keeps on working as I make changes.
Btw someone should keep count, that makes four: python-red, headless-red (browser only), rust red, i.e. EdgeLinkd and Erlang-Red. Anymore?