Conformance testing to real-time communications systems

Real-time requirements appear in the specifications of new evolving systems such as multimedia applications or embedded systems. Testing is an experimental method aimed at checking the correctness of some implementation and its conformance to some standard specification. At present, standardization institutions are being interested in a formal framework for the development of real-time communications systems. Some ISO working groups are proposing formalisms to describe these systems, while other working groups are proposing formalisms to describe real-time test cases. But few works exist on conformance testing aspects, against time-dependencies that bridge the gap between the two previous activities. The contribution of this paper is the proposition of a complete method to the design of tests against real-time communications systems. The proposed method complies to the ITU-T Z500 standard on tests development and we show that the tests designed by our method are sound and exhaustive. The test construction process is also illustrated with an example of time-dependent protocol. (C) 2002 Elsevier Science B.V. All rights reserved.