Preface Piero

Rule-based policy and contract systems have rarely been studied in terms of their software engineering properties. This is a serious omission, because in rule-based policy or contract representation languages rules are being used as a declarative programming language to formalize realworld decision logic and create IS production systems upon. This paper adopts a successful SE methodology, namely test driven development, and discusses how it can be adapted to verification, validation and integrity testing (V&V&I) of policy and contract specifications. Since, the test-driven approach focuses on the behavioral aspects and the drawn conclusions instead of the structure of the rule base and the causes of faults, it is independent of the complexity of the rules and the system under test and thus much easier to use and understand for the rule engineer and the user.