ABSTRACT
Introduction Testing is perhaps the most expensive task of a software project. In one estimate, the testing phase took over 50% of the project resources [1]. Besides causing immediate costs, testing is also importantly related to costs related to poor quality, as malfunctioning programs and errors cause large additional expenses to software producers [1, 2]. In one estimate [2], software producers in United States lose annually 21.2 billion dollars because of inadequate testing and errors found by their customers. By adding the expenses caused by errors to software users, the estimate rises to 59.5 billion dollars, of which 22.2 billion could be saved by making investments on testing infrastructure [2]. erefore improving the quality of software and eectiveness of the testing process can be seen as an eective way to reduce software costs in the long run, both for software developers and users.
