Tactician sets test, gratis (10)
I believe the answer is:
strategist
'tactician' is the definition.
(thesaurus)
'sets test gratis' is the wordplay.
'sets' is an anagram indicator (I've seen 'set' mean this (instruction to set the letters)).
'test'+'gratis'='testgratis'
'testgratis' with letters rearranged gives 'STRATEGIST'.
(Other definitions for strategist that I've seen before include "Expert on the art of planning war" , "general" , "Long-term planner" .)