Save the list of targeted tests on the job artifacts.
Use sed to remove extra content of the diff. Result is a plain list of test names.
To test the sed:
$ diff kpet-empty.list kpet-patch.list
5a6
> LTP: openposix test suite fernet
25a27
> storage: SCSI VPD
$ diff kpet-empty.list kpet-patch.list | sed -e '/> /!d;s/> \(.*\)/\1/'
LTP: openposix test suite fernet
storage: SCSI VPD