Lattice-Based Semantics for Combinatorial Model Evolution

A Visual Logical Language for System Modelling in Combinatorial Test Design

“…For an example, consider the standard toy combinatorial model often used in CTD literature, cf. [13]. Suppose our system is modelled using three parameters:…”

“…As we explain below, this implicit assumption may cause ambiguity and confusion at the time of model construction. In [13] the Boolean semantics is also criticised as inadequate for supporting model evolution. One of the main criticisms is an inconsistent interpretation of test validity in case a new value is added.…”

“…However, according to [6], only 5 % of publications on CTD address the process of constructing combinatorial models. As noted in [13], "An under-explored challenge for wide deployment of CTD in industry is the manual process for modelling and maintaining the test space". Indeed, the task of combinatorial model construction for complex systems heavily relies on tacit human knowledge, and therefore will always remain the task of a human tester.…”

“…The logical languages currently used in CTD tools are based on the standard Boolean semantics. This semantics has been criticised as inadequate for supporting model evolution in [13], where a more sophisticated lattice-based semantics was proposed. In this position paper we point out some implicit assumptions which are made when using Boolean semantics in the context of CTD.…”

“…We propose simple visual constructs to make these assumptions more explicit, thereby reducing the cognitive load of the modeller when specifying the logical restrictions, as well as the chances for human errors. We show how these constructs can be used as an alternative solution to the problems pointed out in [13].…”