Test case involved tape recording (8)
I believe the answer is:
cassette
'tape recording' is the definition.
'cassette' can be an answer for 'recording' (I've seen this before). I'm unsure of the 'tape' bit.
'test case involved' is the wordplay.
'involved' indicates an anagram (involved can mean confusing or complex).
'test'+'case'='testcase'
'testcase' anagrammed gives 'CASSETTE'.
Can you help me to learn more?
(Other definitions for cassette that I've seen before include "Source of music" , "sound equipment" , "Audio tape holder" , "Box of recordings" , "something from old-fashioned language laboratory?" .)