Cassette fixed in legal example for future use (4,4)

I believe the answer is:

test case

I'm a little stuck... Click here to teach me more about this clue!

'legal example for future use' is the definition.
I can't judge whether this definition defines the answer.

'cassette fixed' is the wordplay.
'fixed' indicates an anagram.
'cassette' is an anagram of 'TEST-CASE'.

'in' is the link.

Can you help me to learn more?

(Other definitions for test case that I've seen before include "Legal action where the outcome sets a precedent" , "Precedent established" , "Lawsuit seeking decision asprecedent" , "Forensic proof" , "Legal action where the outcome will serve as a precedent" .)

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.