 This plan is risky. If, through the chance process, the last day happens to be selected, then abiding by the outcome means giving an unsurprising test. For as in the original scenario, the student has knowledge of the teacher’s announcement and awareness of past testless days. So the teacher must exclude random selection of the last day. The student is astute. He will replicate this reasoning that excludes a test on the last day. Can the teacher abide by the random selection of the next to last day? Now the reasoning becomes all too familiar.