Breaking out in test or lesson (8)
I believe the answer is:
tutorial
'lesson' is the definition.
(I've seen this before)
'breaking out in test' is the wordplay.
'breaking' is an anagram indicator.
'in' indicates putting letters inside.
'test' becomes 'trial' (synonyms).
'out' is an anagram of 'uto'.
'uto' going inside 'trial' is 'TUTORIAL'.
'or' acts as a link.
(Other definitions for tutorial that I've seen before include "Seminar" , "Private lesson" , "Personal teaching session" , "University lesson" , "Session of intensive teaching to an individual or small group" .)