Compositional Verification of Input-Output Conformance via CSP Refinement Checking

Abstract

Abstract. This paper contributes to a testing theory, based on the CSP process algebra, whose conformance relation (cspio) distinguishes input and output events. Although cspio has been defined in terms of the standard CSP traces model, we show that our theory can be immediately extended to address deadlock, outputlock and livelock situations if a special output event is used to represent quiescence. This is formally established by showing that this broader view of cspio is equivalent to Tretmans' ioco relation. Furthermore, we address compositional conformance verification, establishing compositionality properties for cspio with respect to process composition operators. Our testing theory has been adopted in an industrial context involving a collaboration with Motorola, whose focus is on the testing of mobile applications. Some examples are presented to illustrate the overall approach.

Compositional Specifications for ioco Testing

“…In order to preserve compositional testing with tioco, specifications are required to be receptive. Compositional properties of the cspio conformance relation for model-based testing with CSP specifications were studied in [10]. CSP operations are shown to be monotonic with respect to cspio when the specifications are input-enabled, or the implementations are not receptive, and after each trace, the input actions accepted by the implementation are a subset of those offered by the specification.…”

An enhanced flow analysis technique for detecting unreachability faults in concurrent systems

“…Tsai and Juan [35] developed heuristic techniques for efficient compositional verification of component-based software systems. Sampaio et al [31] applied the notion of refinement checking in communicating sequential processes (CSP) [29] to compositional verification. Ahrendt and Dylla [1] presented a system for the compositional verification of Creol, an object-oriented model for distributed concurrent applications [20].…”

Testing of Component-Based Systems

“…Compositional testing [15], [20], [22] is viewed as one of the most promising directions to bridge the gap between the increasing complexity of systems and actual testing method limits due to the reasons discussed above. Similarly to compositinality result in [20] establishing under certain hypothesis that the conformance testing relation ioco is compositional with respect to parallel composition and hiding, we have established a compositinality result in [3].…”