Properly test dun learner (7)

I believe the answer is:

student

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'learner' is the definition.
(student is a kind of learner)

'properly test dun' is the wordplay.
'test dun' anagrams to 'STUDENT'.
However, I am not clear how this is indicated.

Can you help me to learn more?

(Other definitions for student that I've seen before include "Maybe fresher" , "Undergraduate maybe" , "collegian" , "Trainee" , "Eg, undergraduate" .)

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

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