The Tester's Pocketbook

Test Axioms

Paul Gerrard introduced the idea of Test Axioms in posts on his blog in the spring of 2008 . Over a few months their definitions evolved and in May 2008 he summarised the thinking behind them and tabulated 16 proposed axioms. Further evolution has occurred and with some changes, they have been used in the Tester's Pocketbook.

There was quite a reaction to the proposed axioms. Some people rejected the idea, saying there were no such things. Others were more supportive and offered new axioms or alternate definitions.

Paul believe's that there are a set of rules or principles that provide a framework for all testing. But there is no single agreed definition of test. This is mostly because every consultant and author has tended to write their own definition to suit their own purposes (and Paul admits to being as guilty as the rest of them). As an industry, we are hamstrung because of this. Our clients are confused, and we get distracted by discussions on definitions because of not-invented-here mentalities and our competitive instincts.

An axiom is something believed to be true, but cannot be proven in any practical way. It could be disproven by experiment or experience and we should be prepared to be proven wrong and welcome attempts to do this.

But some people object to the notion of Test Axioms and say that nothing in testing is certain. There are no axioms. All testing rules, principles, techniques, approaches etc. are heuristic. Heuristics have value in some contexts, but are limited in application, usefulness, accuracy etc. in other contexts. They are limited or fallible in known ways.

Here is a different way of looking at axioms then. The axioms have been defined in a way that testers can, for all practical purposes, regard them as axiomatic. If anyone devises a testing context where the axioms are violated, we need to think again: Perhaps the axiom should be scrapped or changed or its scope of applicability defined.

So far, Paul has not received any concrete examples that invalidate the Test Axioms as stated in the Pocketbook.

The Test Axioms are an attempt to provide a context-neutral set of rules for testing that identify the critical thinking processes and motivations for all test approaches.

You can learn more about the axioms at the Test Axioms website.