I just wrote a detailed comment to a poster only to find out it was a test question and my work was in vain. I think this is silly. I don't want to spin my wheels and put thought into a comment for playing games. I am putting in my volunteer time for this to help other people.
Ok, you are a good person and always pay attention to what you are reviewing.
However, this "test question" feature is not about you. It is about the countless numbers of reviewers who take the cumbersome work of walking through those review queues and up-, down-, or close vote any of those questions or answers. Such work tends to make people inattentive, and some of them sometimes may get tired and may be tempted to repeat the voting of others without reading the related post thoroughly before they vote.
To prevent this, the vendor of the SE sites decided to put in a feature to the system to motivate people to "stay awake". Sure, this can be annoying, but giving users a possibility to switch this feature off would obviously make it quite ineffective, since exactly those people for whom the feature was designed would most probably turn it off. So if you want to use the review queues, you better get used to it.