The Oracle Problem When Testing from MSCs

Message Sequence Charts (MSCs) form a popular language in which scenario-based specifications and models can be written. There has been significant interest in automating aspects of testing from MSCs. This paper concerns the Oracle Problem, in which we have an observation made in testing and wish to know whether this is consistent with the specification. We assume that there is an MSC specification and consider the case where we have entirely independent local testers (local observability) and where the observations of the local testers are logged and brought together (tester observability). It transpires that under local observability the Oracle Problem can be solved in low-order polynomial time if we use sequencing, loops and choices but becomes NP-complete if we also allow parallel components; if we place a bound on the number of parallel components then it again can be solved in polynomial time. For tester observability, the problem is NP-complete when we have either loops or choices. However, it can be solved in low-order polynomial time if we have only one loop, no choices, and no parallel components. If we allow parallel components then the Oracle Problem is NP-complete for tester observability even if we restrict to the case where there are at most two processes

Some rules to transform sequence diagrams into coloured Petri nets

This paper presents a set of rules that allows software engineers to transform the behavior described by a UML 2.0 Sequence Diagram (SD) into a Colored Petri Net (CPN). SDs in UML 2.0 are much richer than in UML 1.x, namely by allowing several traces to be combined in a unique diagram, using high-level operators over interactions. The main purpose of the transformation is to allow the development team to construct animations based on the CPN that can be shown to the users or the clients in order to reproduce the expected scenarios and thus validate them. Thus, non-technical stakeholders are able to discuss and validate the captured requirements. The usage of animation is an important topic in this context, since it permits the user to discuss the system behavior using the problem domain language. A small control application from industry is used to show the applicability of the suggested rules

Toward Extracting π-calculus from UML Sequence and State Diagrams

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Implemeting a component-based tool for interactive synthesis of UML statechart diagrams

The Unified Modeling Language (UML) has an indisputable role in objectoriented software development. It provides several diagram types viewing a system from different perspectives. Currently available systems have relatively modest tool support for comparing, merging, synthesizing, and slicing UML diagrams based on their semantical relationships. Minimally Adequate Synthesizer (MAS) is a tool that synthesizes UML statechart diagrams from sequence diagrams in an interactive manner. It follows Angluin's framework of minimally adequate teacher to infer the desired statechart diagram with the help of membership and equivalence queries. MAS can also synthesize sequence diagrams into an edited or manually constructed statechart diagram. In this paper we discuss problems related to a practical implementation of MAS and its integration with two existing tools (Nokia TED and Rational Rose) supporting UML-based modeling. We also discuss information exchange techniques that could be used to allow the usage of other CASE tools supporting UML

Message sequence charts in the software engineering process

The software development process benefits from the use of Message Sequence Charts (MSC), which is a graphical language for displyaing the interaction behaviour of a system. We describe canonical applications of MSC independent of any software development methodology. We illustrate the use of MSC with a case study: the Meeting Scheduler

Nobody’s perfect: interactive synthesis from parametrized real-time scenarios

ABSTRACT As technical systems keep growing more complex and sophisticated, designing software for the safety-critical coordination between their components becomes increasingly difficult. Verifying and correcting these components already represents a significant part of the development process both with respect to time and cost. Scenario-based synthesis has been put forward as an approach to accelerate the transition from requirements to a correct, verified model. I