I can only think of one way to test it: put a mag in with a round in and rack the slide, remove the mag and pull the trigger(obviously this would be done as safely as possible). Something about this seems very sketchy to me and worries me for some reason. Any one know of anything that could go wrong or a better, far safer feeling way?
If you are on a shooting range with a loaded handgun and you have your sights on the target, observing all four of Cooper's Rules, you can
do this without a magazine in place without worries.
Your pistol will either shoot or it will not shoot. If it shoots, you'll know for certain. This is not anymore dangerous than otherwise shooting your handgun.