Prüfprinzipien

Prüfprinzipien, also known as testing principles, are fundamental guidelines that inform the practice of software testing and quality assurance. They provide a framework for conducting effective and efficient testing activities throughout the software development lifecycle. These principles are not rigid rules but rather best practices that help testers to maximize the value of their efforts and achieve better software quality.

One core principle is that testing shows the presence of defects, not their absence. This means that thorough testing can reveal errors, but it cannot definitively prove that a program is entirely free of bugs. Another key principle is that exhaustive testing is impossible. Given the vast number of possible inputs, execution paths, and environmental conditions, it's not feasible to test every single combination. Therefore, testers must prioritize and use risk-based approaches to focus on the most critical areas.

Prüfprinzipien also emphasize that early testing saves time and money. Defects found early in the development cycle are significantly cheaper and easier to fix than those discovered later, during later testing phases or after release. The principle of defect clustering suggests that most defects tend to be concentrated in a small number of modules or components. Testers should leverage this knowledge to focus their efforts on these high-risk areas.

Furthermore, testing is context-dependent. The approach, methods, and tools used for testing should be adapted to the specific project, its risks, and its requirements. For example, testing a safety-critical system like an airplane's flight control software will require a different rigor and methodology than testing a simple mobile game. Finally, the absence-of-errors fallacy highlights that finding and fixing many defects does not guarantee a useful or usable system. Testing must also ensure that the software meets user needs and expectations.