Scenario-based statistical testing of quality of service requirements

In this paper a general framework is presented for testing time-critical systems and software. The main focus is to derive a state-oriented statistical usage model from a set of usage scenarios in order to automatically generate test cases. We describe a methodology that was developed within the European IST project MaTeLo to ease testing by combining the advantages of formal description techniques, namely MSC, UML and TTCN-3. In the first step of our approach, a MCUM (Markov Chain Usage Model) is constructed. This model represents the formal basis for deriving TTCN-3 test case descriptions to perform executable specification-based tests for the system under test (SUT). In order to be independent. of the chosen specification technique, i.e. MSC or UML sequence diagrams, we have defined an XML-based representation format for the MCUM, called MCML (Markov Chain Markup Language). This format represents a common interface between various tools of the MaTeLo approach. All steps in our methodology do also support the testing of QoS (Quality of Service) requirements that are annoted in a UML profile standard notation.