Multiplexing of Partially Ordered Events

Abstract

Abstract. This paper introduces a method to correctly order events in modelbased testing for concurrent systems, in particular multi-threaded programs, whose events are only partially ordered. For a sequential, centralized tester, we need to merge (local) traces of each component into a (global) trace of a system in such a way that the ordering constraints are observed. To this end, we instrument a multi-threaded program under test so that the order of lock events is visible. This additional information helps a so-called multiplexer to reconstruct a fully serial trace consistent with the partial order. We describe programs and the multiplexer as labeled transition systems and give pseudo-code of the algorithm implementing the latter. The implementation of the algorithm presented is used in an industrial context.

Online testing with model programs

“…For example, often conformance violations were discovered due to observable actions being invoked out of order. In order to produce a valid serialization of the observable actions that happen in concurrent threads, the multiplexing technique [9] was used in the test harness of Bag and in the WP projects.…”

Model-Based Testing of Object-Oriented Reactive Systems with Spec Explorer

“…The second generation of this tool set, Spec Explorer [1], deployed in 2004, is now used on a daily basis by Microsoft product groups for testing operating system components, .NET framework components and other areas. While we can refer the reader to papers [21,30,13,12,36] that describe some aspects of Spec Explorer, this chapter provides a comprehensive survey of the tool and its foundations.…”