Fennel loader?

[HiPhish]

Hello,

I would like to write tests in Fennel. My understanding is that this would be possible by implementing a Fennel runner. Looking at the source code it seems like the files under busted/modules/files implement loaders for Lua, Moonscript and Terra. A loader is a table with two functions load and match, but there is no explanation as to what interface these two functions must implement.

I would like to try my hands at writing a Fennel runner. Is there some explanation, or can someone here please elaborate on the protocol that needs to be implemented?