This paper explains how peer review can be used to teach software testing, an important skill that is typically not carefully taught in most programming courses. The goals of such peer review are (1) to frame testing as a fun and competitive activity, (2) to allow students to learn from each other, (3) to demonstrate the importance of testing by uncovering latent bugs in the students' code, and (4) to provide a mechanism for evaluating testing skills. This paper explains how we added peer review to an honors data structure course without significantly reducing its heavy programming load. We evaluate our intervention by summarizing surveys of student attitudes taken throughout the course.