Conditions for Resolving Observability Problems in Distributed Testing

Controllability and observability problems may manifest themselves during the application of a test or checking sequence in a test architecture where there are multiple remote testers. These problems often require the use of external coordination message exchanges among testers during testing. It is desired to construct a test or checking sequence from the specification of the system under test such that it will be free from these problems without requiring the use of external coordination messages. This paper investigates conditions that allow us to construct such a test or checking sequence. For specifications satisfying these conditions, procedures for constructing subsequences that eliminate the need for using external coordination messages are given.