Distributed test method using logical clocks

Abstract

It is difficult to test a distributed system composed of distributed objects because we cannot control concurrent events occurring in the distributed objects. In this thesis, test sequence generating algorithms using logical clocks are proposed for distributed objects in order to control the concurrent events. Proposed algorithms classify events into either concurrent or causal ones as a result of comparing logical clock values labeled at the events of the test sequence, which is for testing the distributed system. Based on the classification, the algorithms generate additional signals to control concurrent events, and add the signals to the test sequence of the distributed objects. These algorithms are able to solve control-observation problem in a formal way and thus reproduce the test results. In this thesis, algorithms are proposed separately for cases that receiving delay time of outputs is zero or not. Moreover, there is a drawback in the existing distributed test method of which the number of channels among testers increases non-linearly while the number of distributed objects is increasing. To overcome this drawback, the proposed algorithms are modified in order to apply to the remote test architecture and the algorithms are applied to the message exchange, of which receiving delay time of outputs is not zero, for the establishment of Q.2971 network side point-to-multipoint call/connection as an example.