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The missing testing principle

February 3, 2015

 software developer

What is so magical about the number SEVEN? Carlos Varela, the mystical trovador from Cuba, has an enumerative song about the subject … and it seems that everything circles around this symbol.

ISTQB, the International Software Testing Qualifications Board, has establishes seven principles (a heritage of over 40 years) that candidate certified testers, must be aware of and K2-downt (understand). Those principles are:

1. Testing shows presence of defects … but it doesn’t show absence of theme.
2. Exhaustive testing is impossible. Well, not everything can be tested.
3. Early testing. Be there from the very beginning in the development cycle … if possible
4. Defect clustering. Defects stick together like brothers in arms
5. Pesticide paradox. Same test performed many times over, will lead eventually to no defects found … this happens all the time.
6. Testing is context dependent. A car is a car, an aircraft is an aircraft and a submarine is a submarine … they have to be tested differently
7. Absence-of-errors fallacy. No matter how much testing is performed and how sophisticated it is, the user is the one deciding if the product is worthy.

Do these seven principles sound logical and practical? I have been studying testing and quality assurance for quite some time now, including some practical experience. Besides I have been developing for quite many years, and I have to admit that I agree. I have also read and watched tons of material about testing and yet, there is a missing element: the human aspect.

Developers are behind every line of code, documentation or specification being written. What is written comes from a mental model, which in turn is agreed upon by the team and stakeholders. In this context the general user is never present in early development for obvious strategic reasons. This situation brings about a plethora of material to be processed, where mistakes in translation and interpretation are increasingly common.
So, having said that I would append a 8th principle to this list:
8. Defects ALWAYS come from the developers.


From → Philosophy

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