Test case in principle involves student role model (7)
I believe the answer is:
example
'role model' is the definition.
'example' can be an answer for 'model' (synonyms). I'm unsure of the 'role' bit.
'test case in principle involves student' is the wordplay.
'test' becomes 'exam' (synonyms).
'case in' suggests removing the centre (the letters which encase the word are used).
'involves' means one lot of letters goes inside another.
'student' becomes 'L' (as in L-plates for learner drivers).
'principle' with its middle taken out is 'pe'.
'pe' enclosing 'l' is 'ple'.
'exam'+'ple'='EXAMPLE'
Can you help me to learn more?
(Other definitions for example that I've seen before include "Standard" , "Someone to emulate" , "Representative object" , "Characteristic item" , "Something illustrating a general rule" .)