I’ve found HF check on the ground to be rather pointless excercise. In addition to posing a potential fire hazard a functional check on the ground by no means guarantees that SELCAL will work later when needed. And unsatisfactory check means you’ll depart with a known defect or will need to defer it and not be able to use it on the flight as it is unlikely the maintenance would have a spare box hanging around and be able to switch it by departure time.
I know some SOP’s require it but I’d rather skip the ground test and rather rely on previous crews report of it’s functional status.