Add a test which verifies firstresult wrappers
Add a test which verifies firstresult wrappers

This is to expose the regression from issue #71.
Wrappers must return a single value not a list.

pytest-dev/pluggy,nicoddemus/pluggy,RonnyPfannschmidt/pluggy,tgoodlet/pluggy,pytest-dev/pluggy,RonnyPfannschmidt/pluggy,hpk42/pluggy