Tea after test game’s ending (9)
I believe the answer is:
checkmate
'game's ending' is the definition.
(chess)
'tea after test' is the wordplay.
'tea' becomes 'mate' (South American hot drink).
'after' means one lot of letters go next to another.
'test' becomes 'check' (synonyms).
'mate' put after 'check' is 'CHECKMATE'.
(Other definitions for checkmate that I've seen before include "defeat on board" , "Last call in chess" , "The final winning move in chess" , "The final killer move in chess" , "Winning chess position" .)