Writing tests that can be automated is now accepted and helps us to develop high-quality software. However, tests and their architecture must be created with the same care and according to the same rules of clean code as the design of the production code. Test code can also rot. Poorly chosen names, redundancies, and high coupling of test code to implementation details lead to large maintenance efforts and, in the worst case, to the temporary, i.e. usually permanent, deactivation of tests.

This talk will first discuss which advanced onboard tools JUnit 5 already provides for writing well-maintainable tests. Furthermore, we will show you how to make your validation logic more independent from implementation details by writing your own assertion matchers. This will teach you how to make your (test) code more maintainable and robust against refactorings so that even simple modifications do not lead to large-scale adaptations of the test code.