If a genuine one was found, we seem to know WHY you would test them, but HOW would you do it?
Stop evading the question! Your line of arguing is intended to continue postponing a decision and delaying resolution.
"Did you have sex with that woman?"
Instead of replying honestly and in good faith with, "Well, depends upon your definition of 'sex.' But she did suck my d*ck." You would probably insolently respond like Vinnie Barbarino of "Welcome Back, Kotter," when he was lost for a valid answer: "Where? When? What?"
My point still stands: Without a bonafide miracle-worker on our hands, whom we could examine under laboratory conditions, and according to rigorous forensic standards, any such discussion (à la "A miracle-worker would be demonic if...") is pointless / purely academic.
All we can do instead is observe that, in ancient times when hearsay and oral history predominated, the tiny province of Palestine was rife with miracle-workers of every stripe. And in contrast: Today, when we have an established body of scientific methods at our command, they seem to have dried up. (Kinda like how the frequency of UFO sightings has diminished in direct proportion to smartphone use.)
Regards,