1,438 research outputs found

    Complete Model-Based Testing Applied to the Railway Domain

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    Testing is the most important verification technique to assert the correctness of an embedded system. Model-based testing (MBT) is a popular approach that generates test cases from models automatically. For the verification of safety-critical systems, complete MBT strategies are most promising. Complete testing strategies can guarantee that all errors of a certain kind are revealed by the generated test suite, given that the system-under-test fulfils several hypotheses. This work presents a complete testing strategy which is based on equivalence class abstraction. Using this approach, reactive systems, with a potentially infinite input domain but finitely many internal states, can be abstracted to finite-state machines. This allows for the generation of finite test suites providing completeness. However, for a system-under-test, it is hard to prove the validity of the hypotheses which justify the completeness of the applied testing strategy. Therefore, we experimentally evaluate the fault-detection capabilities of our equivalence class testing strategy in this work. We use a novel mutation-analysis strategy which introduces artificial errors to a SystemC model to mimic typical HW/SW integration errors. We provide experimental results that show the adequacy of our approach considering case studies from the railway domain (i.e., a speed-monitoring function and an interlocking-system controller) and from the automotive domain (i.e., an airbag controller). Furthermore, we present extensions to the equivalence class testing strategy. We show that a combination with randomisation and boundary-value selection is able to significantly increase the probability to detect HW/SW integration errors

    TOOL-ASSISTED VALIDATION AND VERIFICATION TECHNIQUES FOR STATE-BASED FORMAL METHODS

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    To tackle the growing complexity of developing modern software systems that usually have embedded and distributed nature, and more and more involve safety critical aspects, formal methods (FMs) have been affirmed as an efficient approach to ensure the quality and correctness of the design, that permits to discover errors yet at the early stages of the system development. Among the several FMs available, some of them can be described as state-based, since they describe systems by using the notions of state and transitions between states. State-based FMs are sometimes preferred since they produce specifications that are more intuitive, being the notions of state and transition close to the notions of program state and program execution that are familiar to any developer. Moreover, state-based FMs are usually executable and permit to be simulated, so having an abstraction of the execution of the system under development. The aim of the thesis is to provide tool-assisted techniques that help the adoption of state-based FMs. In particular we address four main goals: 1) identifying a process for the development of an integrated framework around a formal method. The adoption of a formal method is often prevented by the lack of tools to support the user in the different development activities, as model editing, validation, verification, etc. Moreover, also when tools are available, they have usually been developed to target only one aspect of the system development process. So, having a well-engineered process that helps in the development of concrete notations and tools for a FM can make FMs of practical application. 2) promoting the integration of different FMs. Indeed, having only one formal notation, for doing different formal activities during the development of the system, is preferable than having a different notation for each formal activity. Moreover such notation should be high-level: working with high level notations is definitely easier than working with low-level ones, and the produced specifications are usually more readable. This goal can be seen as a sub-goal of the first goal; indeed, in a framework around a formal method, it should also be possible to integrate other formal methods that better address some particular formal activities. 3) helping the user in writing correct specifications. The basic assumption of any formal technique is that the specification, representing the desired properties of the system or the model of the system, is correct. However, in case the specification is not correct, all the verification activities based on the specification produce results that are meaningless. So, validation techniques should assure that the specification reflects the intended requirements; besides traditional simulation (user-guided or scenario-based), also model review techniques, checking for common quality attributes that any specification should have, are a viable solution. 4) reducing the distance between the formal specification and the actual implementation of the system. Several FMs work on a formal description of the system which is assumed to reflect the actual implementation; however, in practice, the formal specification and the actual implementation could be not conformant. A solution is to obtain the implementation, through refinements steps, from the formal specification, and proving that the refinements steps are correct. A different viable solution is to link the implementation with its formal specification and check, during the program execution, if they are conformant

    Analysis and Verification of Service Contracts

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    SAVCBS 2004 Specification and Verification of Component-Based Systems: Workshop Proceedings

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    This is the proceedings of the 2004 SAVCBS workshop. The workshop is concerned with how formal (i.e., mathematical) techniques can be or should be used to establish a suitable foundation for the specification and verification of component-based systems. Component-based systems are a growing concern for the software engineering community. Specification and reasoning techniques are urgently needed to permit composition of systems from components. Component-based specification and verification is also vital for scaling advanced verification techniques such as extended static analysis and model checking to the size of real systems. The workshop considers formalization of both functional and non-functional behavior, such as performance or reliability

    Model Checking and Model-Based Testing : Improving Their Feasibility by Lazy Techniques, Parallelization, and Other Optimizations

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    This thesis focuses on the lightweight formal method of model-based testing for checking safety properties, and derives a new and more feasible approach. For liveness properties, dynamic testing is impossible, so feasibility is increased by specializing on an important class of properties, livelock freedom, and deriving a more feasible model checking algorithm for it. All mentioned improvements are substantiated by experiments
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