I forget where i read it, whether book or anecdotal, i wanna say there are general rules for testing these
I think first you're supposed to rub the leaves on your skin and see if a rash or reaction occurs. If not you proceed to lick or chew the leaf/stem, spit it out, then await a any reactions...
This continues to consuming a small piece, then the fruit, ... Etc.
Again just what i remember hearing before