It's comes as a test to twist it up inside to parcel a rope (4)
I believe the answer is:
oral
'it's comes as a test to twist it' is the definition.
I can't judge whether this definition defines the answer.
'up inside to parcel a rope' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'inside' says the answer is hidden in the clue.
'laro' can be found hidden inside 'to parcel a rope'.
'laro' written backwards gives 'ORAL'.
Can you help me to learn more?
(Other definitions for oral that I've seen before include "language exam" , "Spoken - examination" , "By word of mouth, say exam" , "Mouth-related" , "'Spoken, not written (4)'" .)