Software testing and debugging are often seen as tedious, making them challenging to teach effectively. We present Sojourner under Sabotage, a browser-based serious game that enhances learning through interactive, narrative-driven challenges. Players act as spaceship crew members, using unit tests and debugging techniques to fix sabotaged components. Sojourner under Sabotage provides hands-on experience with the real-world testing framework JUnit, improving student engagement, test coverage, and debugging skills.