Abstract. We provide precise high-level models for eight fundamental service interaction patterns, together with schemes for their composition into complex service-based business process interconnections and interaction flows, supporting software-engineered business process management in multi-party collaborative environments. The mathematical nature of our models provides a basis for a rigorous execution-platform-independent analysis, in particular for benchmarking web services functionality. The models can also serve as accurate standard specifications, subject to further design leading by stepwise refinement to implementations. We begin by defining succinct rigorous models to mathematically capture the behavioral meaning of four basic bilateral business process interaction patterns (Sect. 1), together with their refinements to four basic multilateral interaction patterns (Sect. 2). We then illustrate with characteristic examples how by appropriate combinations and refinements of these eight fundamental patterns one can define arbitrarily complex interaction patterns of distributed service-based business processes that go beyond simple request-response sequences and may involve a dynamically evolving number of participants. This leads to a definition of the concept of process interaction flow or conversation,

Testing is one of the costliest aspects of commercial software development. Model-based testing is a promising approach addressing these deficits. At Microsoft, model-based testing technology developed by the Foundations of Software Engineering group in Microsoft Research has been used since 2003. The second generation of this tool set, Spec Explorer, 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. This chapter provides a comprehensive survey of the concepts of the tool and their foundations. 1

Abstract. On-the-fly testing is a technique in which test derivation from a model program and test execution are combined into a single algorithm. It can also be called online testing using a model program, to distinguish it from offline test generation as a separate process. We describe a practical on-the-fly testing algorithm that is implemented in the model-based testing tool developed at Microsoft Research called Spec Explorer. Spec Explorer is being used daily by several Microsoft product groups. Model programs in Spec Explorer are written in a high level specification language AsmL or Spec#. We view model programs as implicit definitions of interface automata. The conformance relation between a model and an implementation under test is formalized in terms of refinement between interface automata, and testing amounts to a game between the test tool and the implementation under test. 1

The Abstract State Machines (ASMs) theory has been applied to rigorously formalize the semantics of the C♯ programming language. The developed ASM model is validated here by providing an executable model which supports the experimentation with the ASM model. The executable model is a refinement of the ground model and is implemented in AsmL – the Abstract State Machine Language, which is embedded into Microsoft Visual Studio.NET. We report here on the development of AsmL Executable Specifications of the C♯ semantics by depicting our techniques on building and using AsmL as a Specification Language.