I really do not want to risk losing a great image with a clip test. I would rather gamble on getting all acceptably scannable images than losing the one really great image to a slice.
I've had good luck performing a test based on the one described
here (and also
here) for determining development times with found film. With this method you really only need to cut a narrow strip (say, 1 cm wide or so) from the end of the roll, which makes it unlikely that you will intrude into an image frame. I have to say
unlikely rather than certain because I have had a couple cases where an image ended up closer than it should have been to the end of the roll, probably due to the original owner not loading the film correctly. But otherwise it is pretty safe.
For a variety of reasons, my preference is to cut the strip from the leading (taped) end of the roll. If you do the same, note that the strip needs to extend beyond where the tape is (or was) since development comes out different on the film where the tape was located. Another tip for reducing the chances of interfering with an image is that if you develop with stainless reels and like to attach the end of the roll to the little clip, then you should probably choose the un-cut end of the roll to go in first. Alternatively, if you know the roll was only partially exposed to begin with, then definitely the tail end should go in first.