A Comparison of State-Based Modelling Tools for Model Validation

In model-based testing, one of the biggest decisions taken before modelling is the modelling language and the model analysis tool to be used to model the system under investigation. UML, Alloy and Z are examples of popular state-based modelling languages. In the literature, there has been research about the similarities and the differences between modelling languages. However, we believe that, in addition to recognising the expressive power of modelling languages, it is crucial to detect the capabilities and the weaknesses of analysis tools that parse and analyse models written in these languages. In order to explore this area, we have chosen four model analysis tools: USE, Alloy Analyzer, ZLive and ProZ and observed how modelling and validation stages of MBT are handled by these tools for the same system. Through this experiment, we not only concretise the tasks that form the modelling and validation stages of MBT process, but also reveal how efficiently these tasks are carried out in different tools

Putting formal specifications under the magnifying glass: Model-based testing for validation

A software development process is effectively an abstract form of model transformation, starting from an end-user model of requirements, through to a system model for which code can be automatically generated. The success (or failure) of such a transformation depends substantially on obtaining a correct, well-formed initial model that captures user concerns. Model-based testing automates black box testing based on the model of the system under analysis. This paper proposes and evaluates a novel model-based testing technique that aims to reveal specification/requirement-related errors by generating test cases from a test model and exercising them on the design model. The case study outlined in the paper shows that a separate test model not only increases the level of objectivity of the requirements, but also supports the validation of the system under test through test case generation. The results obtained from the case study support the hypothesis that there may be discrepancies between the formal specification of the system modeled at developer end and the problem to be solved, and using solely formal verification methods may not be sufficient to reveal these. The approach presented in this paper aims at providing means to obtain greater confidence in the design model that is used as the basis for code generation

Observations for Assertion-based Scenarios in the context of Model Validation

Certain approaches to Model-Based Testing focus on test case generation from assertions and invariants, e.g., written in the Object Constraint Language. In such a setting, assertions and invariants must be validated. Validation can be carried out via executing scenarios wherein system operations are applied to detect unsatisfied invariants or failed assertions. This paper aims to improve our understanding of how to write useful validation scenarios for assertions in OCL. To do so, we report on our experiences during the creation and execution of 237 scenarios for validating assertions for the Mondex Smart Card application. We also describe key factors that must be considered in transforming scenarios into test cases

Evaluation of OCL for Large-Scale Modelling: A Different View of the Mondex Smart Card Application

Abstract. OCL is used to add rigour to UML/MOF models, and in particular can be used to express behavioural details (e.g., operation preand postconditions, class invariants) of such models. The applicability and utility of OCL can be assessed by applying it to realistic applications and by investigating its capabilities both in terms of language characteristics and tool support. With this in mind, in this paper we model functional requirements for the Mondex Smart Card Application using UML Diagrams, demonstrate how system invariants as well as operation pre- and post-conditions are specified in OCL, and explore the degree to which OCL tool support can be used to create and validate these models. Moreover, we discuss how these pre- and post-conditions can be validated, in part by discussing how test cases can be selected from the OCL specifications created.