Test sequence generation from formal specifications of distributed programs

An abstract program is a formal specification that describes the valid behavior of a distributed program without describing particular implementation mechanisms that achieve this behavior. Valid behavior can be modeled as the possible sequences of events that may be observed of a conforming concrete implementation of the abstract program. In this paper, we address the problem of how to select event sequences from an abstract program to test its concrete implementation. Sequencing constraints make explicit certain types of required properties that are expressed only implicitly by an abstract program. The sequencing constraints derived from an abstract program can be used to guide the selection of event sequences during testing. We describe a constraint notation called CSPE and show how to achieve coverage and detect violations of abstract CSPE constraints. Abstract constraints address the problem of how to compare two programs written at different levels of abstraction. Results of an empirical study of CSPE-based testing are reported.