Syntactic Abstraction of B Models to Generate Tests

TL;DR

This paper introduces a syntactic abstraction method for B models that simplifies state spaces by variable elimination, aiding in test generation and verification for industrial applications.

Contribution

It presents a novel syntactic transformation for B models, combining variable elimination with domain abstraction, and proposes two methods to compute finite abstractions as simulation or bisimulation.

Findings

Produces finite state systems from B models

Enhances test generation efficiency

Applicable to industrial model-based testing

Abstract

In a model-based testing approach as well as for the verification of properties, B models provide an interesting 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, often combining state variable elimination and domain abstractions of the remaining variables. This paper complements previous results, 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 a method that chooses relevant variables according to a test purpose. We propose two methods to compute an abstraction A of an initial model M. The first one computes A as a simulation of M, and the second one computes A as a bisimulation of M. The abstraction process produces a finite state system. We apply this abstraction computation to a Model Based Testing process.