Testing plays a crucial role in software development, and it is essential for software engineering students to receive proper testing education. However, motivating students to write tests and use automated testing during software development can be challenging. To address this issue and enhance student engagement in testing when they write code, we propose to incentivize students to test more by gamifying continuous integration. For this we use Gamekins, a tool that is seamlessly integrated into the Jenkins continuous integration platform and uses game elements based on commits to the source code repository: Developers can earn points by completing test challenges and quests generated by Gamekins, compete with other developers or teams on a leaderboard, and receive achievements for their test-related accomplishments. In this paper, we present our integration of Gamekins into an undergraduate-level course on software testing. We observe a correlation between how students test their code and their use of Gamekins, as well as a significant improvement in the accuracy of their results compared to a previous iteration of the course without gamification. As a further indicator of how this approach improves testing behavior, the students reported enjoyment in writing tests with Gamekins.