Detecting behavioural incompatibilities between pairs of services?

Abstract. We present a technique to analyse successive versions of a service interface in order to detect changes that cause clients using an earlier version not to interact properly with a later version. We focus on behavioural incompatibilities and adopt the notion of simulation as a basis for determining if a new version of a service is behaviourally com-patible with a previous one. Unlike prior work, our technique does not simply check if the new version of the service simulates the previous one. Instead, in the case of incompatible versions, the technique provides de-tailed diagnostics, including a list of incompatibilities and specific states in which these incompatibilities occur. The technique has been imple-mented in a tool that visually pinpoints a set of changes that cause one behavioural interface not to simulate another one.