APSL: A light weight testing tool for protocols with complex messages

Abstract

Many real world communication protocols exchange complex messages, consisting of multiple nested fields, some could have values that depend on other fields. To properly test an implementation, it is not sufficient to only explore different orders of message exchanges. We also need to test if the implementation produces correctly formatted messages, and responds correctly when it receives different variations of every message type. This paper presents a light weight model based testing tool called APSL. Models are described as labelled transitions systems, from which abstract test sequences can be generated. APSL’s main contribution is in its language for describing complex message formats, text-based or binary, allowing APSL to automatically concretize abstract test sequences, and check incoming messages for their type and format conformance. Testing works out thus of the box: developers do not need to first write a dedicated concretization layer, which would otherwise require substantial investment.