It is challenging to teach software testing in a way that is engaging for students, and to ensure that they practice effective testing sufficiently. Code Defenders is an educational game that is intended to address this problem: Students compete over code under test by either introducing faults (“attacking”) or by writing tests (“defending”). We have integrated Code Defenders as a mandatory component of a software testing course at the University of Passau, which featured ten game sessions of two hours each and involved 120 students. In this paper, we describe how this integration took place and provide some initial insights into our experiences. Code Defenders and the course material are freely available, allowing others to replicate this setup and to gamify their own testing courses.