Testability-directed specification of communications software.

Abstract

In this thesis, we make a contribution to improving software testability by providing a useful model and guide-lines for constructing highly testable specifications of distributed real time (communications) systems. A global events model is developed based on relative clock for interpreting concurrent aspect of a communications system. Extended trace assertion language (ETAL) is presented for formally representing both the sequential and concurrent aspects of the system. A relative clock based specification in ETAL method also facilitates subsequent testing activity. Subsequently, based on the global events model, a new test result analysis approach including timing information is presented for communication service and protocol conformance testing. This approach is also ETAL specification-based. After the descriptions of the contributions mentioned above, the definition of a testability-directed specification and a study on the relations between the testability-directed specification and ETAL are then presented. Finally, the feasibility and usefulness of the relative clock based formal specification method is demonstrated by its application to OSI transport software (service and protocol). Also, the effectiveness of the relative clock based approach for test result analysis is illustrated in a set of realistic conformance testing examples. (Abstract shortened by UMI.)