 For this, among other reasons, the traditional notion of scientific experiment needs to be ‘stretched’ in order to be applied to software testing activities (Schiaffonati 2015). Theory-driven experiments, characterizing most of the experimental sciences, find no counterpart in actual computer science practice. If one excludes the cases wherein testing is combined with formal methods, most experiments performed by software engineers are rather explorative, i.e. aimed at ‘exploring’ “the realm of possibilities pertaining to the functioning of an artefact and its interaction with the environment in the absence of a proper theory or theoretical background” (Schiaffonati 2015: 662). Software testers often do not have theoretical control on the experiments they perform; exploration on the behaviors of the computational system interacting with users and environments rather allows testers to formulate theoretical generalizations on the observed behaviors. Explorative experiments in computer science are also characterized by the fact that programs are often tested in a real-like environment wherein testers play the role of users. However, it is an essential feature of theory-driven experiments that experimenters do not take part in the experiment to be carried out.