Function and Performance of Testing: Towards a Systemic View

The belief that function and performance may be addressed separately is a part of the popular reductionist mindset. On the other hand, the growing complexity of Information Systems calls for "systems thinking" - a holistic approach that challenges the reductionist theses. Here we apply the latter to testing. We assume the function of testing to be the disposition to issue valid (sound) verdicts. It is then shown that a tester, commonly defined in terms of its untimed Discrete Event behaviour, nontrivially relies on various components of its performance to execute this function. The submitted view on performance consists in distinguishing its three components: syntactic, semantic, and pragmatic. Discussion is set in a wider context of control loops that employ a tester as a judgemental element (eventually to ensure trustworthy operation of a system), and is illustrated with a case study concerned with passive testing in the presence of infidelity.