Where a test confused a lover (10)
I believe the answer is:
sweetheart
'a lover' is the definition.
(I know that sweetheart is a type of lover)
'where a test confused' is the wordplay.
'confused' is an anagram indicator.
'where'+'a'+'test'='whereatest'
'whereatest' anagrammed gives 'SWEETHEART'.
(Other definitions for sweetheart that I've seen before include "boyfriend?" , "baby" , "Boy- or girlfriend" , "Beloved" , "Darling" .)