Software Testing

Abstract

Testing is the process of sampling the executions of a system according to some given criterion. Each execution is compared with the specification, and any mismatch is reported as an error. Since testing is usually based on sampling of the system executions, rather than on systematically checking all of them, it is not considered to be an exhaustive check guaranteed to cover all possible errors. It provides a lesser guarantee than the more comprehensive formal methods presented in previous chapters. Thus, some researchers do not even include testing within formal methods. However, testing does provide a practical solution in the case where a given system is so large that it defies manual or automatic verification. In fact, testing is by and large the most commonly used method for enhancing the quality of software.

... and tied round the neck of the bottle was a paper label, with the words “DRINK ME” beautifully printed on it in large letters. It was all very well to say ‘Drink me,’ but the wise little Alice was not going to do that in a hurry. ‘No, I’ll look first, ’ she said, ‘and see whether it’s marked “poison” or not’.

Lewis Carroll, Alice’s Adventures in Wonderland