B model slicing and predicate abstraction to generate tests

Abstract

In a model-based testing approach as well as for the verification of properties, B models provide an interesting modelling solution. However, for industrial applications, the size of their state space often makes them hard to handle. To reduce the amount of states, an abstraction function can be used. The abstraction is often a domain abstraction of the state variables that requires many proof obligations to be discharged, which can be very time consuming for real applications.This paper presents a contribution to this problem that complements an approach based on domain abstraction for test generation, by adding a preliminary syntactic abstraction phase, based on variable elimination. We define a syntactic transformation that suppresses some variables from a B event model, in addition to three methods that choose relevant variables according to a test purpose. In this way, we propose a method that computes an abstraction of a source model M according to a set of selected relevant variables. Depending on the method used, the abstraction can be computed as a simulation or as a bisimulation of M. With this approach, the abstraction process produces a finite state system. We apply this abstraction computation to a Model Based Testing process. We evaluate experimentally the impact of the model simplification by variables elimination on the size of the models, on the number of proof obligations to discharge, on the precision of the abstraction and on the coverage achieved by the test generation.

Literature Analysis on Model based Slicing

“…Samuel et.al [24] proposed a schema known as 'Ctest' that automatically generate test cases from UML communication diagram. According to schema the first step of the approach is to construct communication tree from communication diagram on the basis of data flow and control flow.…”

A practical approach for model based slicing

“…Archer et al [19] proposed a novel slicing technique on the feature model by taking cross-tree constraints into account with respect to set of features which are acting as slicing criteria. Julliand et.al [20] proposed an approach based on domain abstraction for generating test cases on the basis of syntactic abstraction and variable elimination with the help of model slicing.…”