Test development for communication protocols: towards automation

In this paper we give an introduction to methods and tools for testing comm unication protocols and distributed systems. In this context, we try to ans wer the following questions: Why are we testing? What are we testing? Again st what are we testing?... We present the different approaches of test auto mation and explain the industrial point of view (automatic test execution) and the research point of view (automatic test generation). The complete au tomation of the testing process requires the use of formal methods for prov iding a model of the required system behavior. We show the importance of mo delling the aspects to be tested (the right model for the right problem!) a nd point out the different aspects of interest (control, data, time and com munication). We present the problem of testing based on models, in the form of finite state machines (FSMs), extended FSMs, timed FSMs and communicati ng FSMs, and give an overview of the proposed solutions and their limitatio ns. Finally, we present our own experience in automatic test generation bas ed on SDL specifications, and discuss some related work and existing tools. (C) 1999 Elsevier Science B.V. All rights reserved.