Ugh. One of my least favorite topics... at least the standardized kind. I don't mind authentic assessments (portfolios, discussions, presentations, projects, etc). However, the standardized kind do send chills up my spine when I think about them....young children sitting at a desk, not allowed to ask any questions, taking a test that is 60 questions long in one sitting.
You can download a few sample practice tests onto cardstock and cut the questions apart. It is better to only put one question per card as not to overwhelm them. (I do a google search for "tennessee state tcap practice tests" and find a wealth of resources to use.)
You can place the question cards in a small box to be used as another rotation in learning material. Put the answer to the question on the back (or create an "answer sheet") so the child can self-check. I often talk with my children about how multiple choice questions are worded and how they can be tricky. I also found a "bubble sheet" maker where I create bubble sheets so they can fill in the bubble to answer the question. Right now, I only do a 5 question answer sheet. When it gets closer to time for them to take the actual test, you will want to create longer ones to give them an idea of what to expect.