Design for testability of communication protocols

• Main Author: Loureiro, Antonio Alfredo Ferreira
• Format: Others
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/4776

There is growing consensus that some design principles are needed to overcome the ever increasing complexity in verifying and testing software in order to build more reliable systems. Design for testability (DFT) is the process of applying techniques and methods during the design phase in order to reduce the effort and cost in testing its implementations. In this thesis, the problem of design for testability of communication protocols is studied. A framework that provides a general treatment to the problem of designing communication protocols with testability in mind and some basic design principles are presented. Following the protocol engineering life cycle we have identified and discussed in detail issues related to design for testability in the analysis, design, implementation, and testing phases. We discuss two important aspects that affect the testing of communication protocols: testing taking the environment into consideration and distributed testing. We present a novel algorithm and the corresponding design principles for tackling an important class of faults caused by an unreliable environment, namely coordination loss, that are very difficult to catch in the testing process. These design principles can be applied systematically in the design of self-stabilizing protocols. We show that conformance relations that are environment independent are not adequate to deal with errors caused by the environment such as coordination loss. A more realistic conformance relation based on external behavior as well as a "more testable" relation for environments which exhibit coordination loss are introduced. We also present a novel algorithm and the corresponding design principles for checking dynamic unstable properties during the testing process. The method proposed can be used in distributed testing of communication protocols and distributed programs in general. This technique can also be used in normal execution of the protocol implementation to tackle the problems of state build-up and exception handling when a fault is detected. A specific type of communication protocol, namely 3-way handshake protocols, is used to show it is possible to check general properties using this algorithm. A comprehensive survey of testability and design for testability in the software domain is also included in the thesis. === Science, Faculty of === Computer Science, Department of === Graduate