ABSENCE-OF-ERRORS IS A FALLACY

Absence-of-error is a fallacy. Software with no known errors is not necessarily ready to be shipped. Does it match user/business expectations?

As part of the Seven Testing Principles of the ISTQB Foundation Level Syllabus, the absence-of-error is a fallacy principle.

“Some organizations expect that testers can run all possible tests and find all possible defects, but principles 2 and 1, respectively, tell us that this is impossible. Further, it is a fallacy (i.e., a mistaken belief) to expect that just finding and fixing a large number of defects will ensure the success of a system. For example, thoroughly testing all specified requirements and fixing all defects found could still produce a system that is difficult to use, that does not fulfil the users’ needs and expectations, or that is inferior compared to other competing systems.” ISTQB Foundation Syllabus

To make sure that these principles are applied, every tester should ask themselves basic questions such as “What is the purpose of my testing?” or “What should my testing achieve?”. Furthermore, every tester should regularly review the principles to make sure that their testing activities are based on them.

The test principles presented here are not exhaustive, and they are not intended to be a checklist with which to assess the quality of your testing. Rather, they are meant to be a starting point for your own reflections about testing and for conversations about the importance of testing.

As we have seen, a thorough understanding of testing principles leads to better testing practices and better results.