BEAM just gets better and better. It's a good time to be an Erlanger/Elixirist...
I've looked into this in more details in the past. We've had success just writing our own test runner and avoiding exs files. But re-implementing things like running tests based on line number, or integrating with external tools (like excoveralls) has been a dealbreaker.
Unfortunately, it is a bit too large (and too late) for v1.12, but if loading times have been problematic for you, it would be awesome if you could try master out and let us know in the issues tracker (or in the commit) if you see any improvements.
Not comparable to going from a Javascript interpreter to v8.
But it's a great starting point.
It won't be anything like V8, entirely correct, but it brings some VM code to native performance, beating NIFs in some cases.
I think some RabbitMQ tests reported 30% increase in throughput which is pretty wild.