Testing software is a critically important process. The ability of students to identify a set of important test cases communicates their understanding of the design specifications and potential issues due to implementation choices. Students select and apply their own test cases to cover both general behavior and the edge cases which show behavior at boundary conditions. For example, for a program that is supposed to accept test scores in the range of [0,100], students could develop appropriate tests (e.g, a negative value, 0, 100, and a value above 100). Alternatively, students developing an app to allow users to create and store calendar appointments could develop and use a series of test cases for various scenarios including checking for correct dates, flagging for user confirmation when a calendar event is very long, checking for correct email address format for invitees, and checking for appropriate screen display as users go through the process of adding, editing, and deleting events.