One released by a soldier sorted out difficult tests (7)
I believe the answer is:
ordeals
'difficult tests' is the definition.
(I've seen this before)
'one released by a soldier' is the wordplay.
'one released' becomes 'deals' (I can't explain this - if you can you should believe this answer much more).
'by' says to put letters next to each other.
'a soldier' becomes 'OR' (soldier from Other Ranks).
'deals' after 'or' is 'ORDEALS'.
'sorted out' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ordeals that I've seen before include "Trying experiences" , "difficult tests" , "Tribulations" , "Testing experiences" , "Difficult experiences, hard times" .)