Minor gets four in a test (7)
I believe the answer is:
trivial
'minor' is the definition.
(minor can mean trivial or unimportant)
'four in a test' is the wordplay.
'four' becomes 'IV' (Roman numerals).
'in' means one lot of letters goes inside another.
'a test' becomes 'trial' ('trial' can be a synonym of 'test').
'iv' put inside 'trial' is 'TRIVIAL'.
'gets' is the link.
(Other definitions for trivial that I've seen before include "Petty, piffling" , "Frivolous" , "Of little value" , "Rinky-dink" , "Popular board game" .)