There are a few options. You can use the commandline and wire it up with any commandline unit frameowrk (/WEB-INF/myna/commandline/myna).
I have an node-style require framework and test suite I have been playing with, but I haven't ported to Myna yet. I'm still trying to decide if Nashorn is really worth the effort or if I should just back port some of that code to regular Myna.