Software is continuously increasing in complexity. Paradigmatic shifts and new development frameworks make it easier to implement software - but not to test it. Software testing remains to be a topic with many open questions with regard to both technical low-level aspects and to the organizational embedding of testing. However, a desired level of software quality cannot be achieved by either choosing a technical procedure or by optimizing testing processes. In fact, it requires a holistic approach.This Brief summarizes the current knowledge of software testing and introduces three current...