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This thesis examines applying formal methods to software testing. Software testing is a critical phase of the software life-cycle which can be very effective if performed rigorously. Formal specifications offer the bases for rigorous testing practices. Not surprisingly, the most immediate use of formal specifications in software testing is as sources of black-box test suites. However, formal specifications have more uses in software testing than merely being sources for test data. We examine these uses, and show how to get more assistance and benefit from formal methods in software testing. At the core of this work is a exible framework in which to conduct specification-based testing. The framework is founded on formal definitions of tests and test suites, which directly addresses important issues in managing software testing. This provides a uniform platform for other applications of formal methods to testing such as analysis and reification of tests, and also for applications beyond testing such as maintenance and specification validation. The framework has to be exible so that any testing strategies can be used. We examine the need to adapt certain strategies to work with the framework and formal specification. Our experiments showed some deficiencies that arise when using derivation strategies on abstract specifications. These deficiencies led us to develop two new specification-based testing strategies based on extensions to existing strate- gies. We demonstrate the framework, strategies, and other applications of formal methods to software testing using three case studies. In each of these, the framework was easy to use. It provided an elegant and powerful means for defining and structuring tests, and a suitable staging ground for other applications of formal methods to software testing. This thesis demonstrates how formal specification techniques can systematise the application of testing strategies, and also how the concepts of software testing can be combined with formal specifications to extend the role of the formal specification in software development.

La phase la plus consommatrice de ressources d'une production de logiciels est l'étape de vérification qualité, incluant la vérification fonctionnelle des programmes. Donc, à cause de ces coûts, l'industrie de développement des logiciels exécute rarement une vérification minutieuse de ses produits. Une des stratégies les plus prometteuses pour réduire les coûts de vérification des logiciels est de rendre cette vérification aussi automatique que possible. Actuellement, cette industrie repose essentiellement sur une seule phase de tests pour vérifier les fonctionnalités des programmes. Nous avons donc cherché à automatiser le test fonctionnel des logiciels en fournissant une assistance pour l'étape de génération des scénarios de test. Le test basé sur des modèles (MBT) est une théorie de test qui a eu un grand succès dans l'automatisation du processus de test. Une méthode MBT analyse un modèle formel ou une spécification d'un logiciel pour produire des scénarios de test qui sont exécutés plus tard par le programme. La plupart de ces méthodes travaillent avec des machines à états finis (FSM) qui limite leur application puisque les FSMs ne peuvent pas décrire tous les logiciels. Cependant, un gros avantage de ces méthodes est qu'elles atteignent un haut degré d'automatisation. Dans cette thèse nous montrons, au contraire, le niveau d'automatisation que nous avons obtenu en appliquant une méthode MBT, connue comme Test Template Framework (TTF), sur des spécifications Z. Comme Z est basé sur la logique de premier ordre et la théorie du jeu, il est beaucoup plus expressif que les FSMs, rendant ainsi nos résultats applicables à une plus large gamme de programmes. / The most resource-consuming phase of software production is the verification of its qualities, including functional correctness. However, due to its costs, the software industry seldom performs a thorough verification of its products. One of the most promising strategies to reduce the costs of software verification is making it as automatic as possible. Currently, this industry relies basically only on testing to verify functional correctness. Therefore, we sought to automate functional testing of software systems by providing tool support for the test case generation step. Model-based testing (MBT) is a testing theory that has achieved impressive successes in automating the testing process. Any MBT method analyses a formal model or specification of the system under test to generate test cases that later are executed on the system. Almost all methods work with some form of finite state machines (FSM) which limits their application since FSM's cannot describe general systems. However, a great advantage of these methods is that they reach a high degree of automation. In this thesis we show, on the contrary, the degree of automation we have achieved by applying a MBT method, known as Test Template Framework (TTF), to Z specifications. Since Z is based on first-order logic and set theory it is far more expressive than FSM's, thus making our results applicable to a wider range of programs. During this thesis we have improved the TTF and developed a tool, called Fastest, that implements all of our ideas.

Business Process Modelling Notation (BPMN) is a standardised diagram notation for modelling interactive workflow processes graphically at the design stage. The primary objective of this thesis is to provide a framework for precise specifications and formal verifications of workflow processes modelled as BPMN diagrams. We provide two behavioural semantics for BPMN in the process algebra Communicating Sequential Processes (CSP). We apply existing CSP refinement orderings to both the refinement of business process diagrams and the verification of behavioural compatibility of business process collaborations. The first semantic model is an untimed model, focusing on the control flow and communication of business processes. The second semantic model extends the first one to capture the timing aspect of behaviour. We also consider the applications of the semantic models. The secondary objective of this thesis is to apply BPMN and the semantic models to reason about long running empirical studies (e.g. laboratory experiments, clinical trials). We introduce a declarative workflow model Empiricol for recording trials and experiments precisely, and define bidirectional transformation functions between BPMN and Empiricol. Using the transformation functions, we make graphical specification, simulation, automation and verification of trials and experiments possible. We provide two case studies on the applications of BPMN’s formalisations.

Especificações formais são úteis para descrever o que um sistema deve fazer sem definir como, e, em virtude da sua natureza formal e da possibilidade de abstração, é possível analisá-las sistematicamente. No entanto, o uso de especificações formais como parte do desenvolvimento de software não constitui prática comum. Isso se dá, em parte, pelo fato de existirem apenas um pequeno número de metodologias e ferramentas adequadas que dêem suporte a esse desenvolvimento. O primeiro objetivo deste trabalho é propor uma metodologia de desenvolvimento que possibilite, a partir de uma especificação formal em notação Z, produzir uma implementação dessa especificação em Java. Essa metodologia centra-se na geração do esqueleto da aplicação Java e na instrumentação desse esqueleto com mecanismos de verificação de condições (invariantes, pré e pós-condições) e rastreamento de violações dessas condições. Através desses mecanismos, possibilita-se intercalar desenvolvimento formal e informal no processo global de desenvolvimento de software. O segundo objetivo é desenvolver uma ferramenta que implemente parte dessa metodologia, produzindo uma implementação parcial que deverá ser complementada pelo usuário. / Formal specifications are useful for describing what a system should do, without defining how, and, owing to its formal nature, it is possible to analyse them systematically. However useful formal specifications are, their usage as part of the software development process is rather rare. This is, in part, due to the scarcity of both methodologies and tools that support this development. The first goal of this work is to define a software development methodology that enables the developer to produce a Java application from a formal specification written in Z. This methodology will rely strongly on the generation of Java application skeletons and instrumentation of the generated code with means of verifying conditions (invariants, pre and post-conditions) e tracing violations of these conditions. Through this mechanisms, it is possible to mix formal and informal development in the global software development process. The second goal of this work is to develop a tool that will implement part of this methodology, producing a partial implementation that must be complemented by the developer.

Especificações formais são úteis para descrever o que um sistema deve fazer sem definir como, e, em virtude da sua natureza formal e da possibilidade de abstração, é possível analisá-las sistematicamente. No entanto, o uso de especificações formais como parte do desenvolvimento de software não constitui prática comum. Isso se dá, em parte, pelo fato de existirem apenas um pequeno número de metodologias e ferramentas adequadas que dêem suporte a esse desenvolvimento. O primeiro objetivo deste trabalho é propor uma metodologia de desenvolvimento que possibilite, a partir de uma especificação formal em notação Z, produzir uma implementação dessa especificação em Java. Essa metodologia centra-se na geração do esqueleto da aplicação Java e na instrumentação desse esqueleto com mecanismos de verificação de condições (invariantes, pré e pós-condições) e rastreamento de violações dessas condições. Através desses mecanismos, possibilita-se intercalar desenvolvimento formal e informal no processo global de desenvolvimento de software. O segundo objetivo é desenvolver uma ferramenta que implemente parte dessa metodologia, produzindo uma implementação parcial que deverá ser complementada pelo usuário. / Formal specifications are useful for describing what a system should do, without defining how, and, owing to its formal nature, it is possible to analyse them systematically. However useful formal specifications are, their usage as part of the software development process is rather rare. This is, in part, due to the scarcity of both methodologies and tools that support this development. The first goal of this work is to define a software development methodology that enables the developer to produce a Java application from a formal specification written in Z. This methodology will rely strongly on the generation of Java application skeletons and instrumentation of the generated code with means of verifying conditions (invariants, pre and post-conditions) e tracing violations of these conditions. Through this mechanisms, it is possible to mix formal and informal development in the global software development process. The second goal of this work is to develop a tool that will implement part of this methodology, producing a partial implementation that must be complemented by the developer.

The development of Digital Twin Technology, with a focus on addressing environmental concerns, has elevated the priority of Industry 4.0-based solutions. The study aimed to design a simulation model to optimize the electricity consumption of the electric bus fleet at Arlanda Airport as a subproject of the main Digital Twin project. The study found that there was no current model designed to simulate electricity consumption by formal methods, Z notation.  The research is guided by four primary objectives find power management strategies for e-buses, identify critical parameters affecting their energy consumption, create a Z Notation simulation model, and assess this model. Through a thorough review of the literature and methodical application, power management strategies were defined, and significant energy consumption parameters were identified. The model's usefulness in modelling and optimizing electricity usage was demonstrated by its careful construction using Z Notation and evaluation with Spivey's Fuzz Checker. The paper demonstrates the use of Design Science Research in creating a digital twin-based simulation, which has important implications for transportation systems as well as theoretical advances in simulation methodologies. Throughout the developed Z notations, it provide a proper insight into operational efficiency and sustainability in energy consumption.  The study also emphasizes the drawbacks of using Z Notation, such as its steep learning curve and limited community assistance. To improve the accuracy of electricity consumption forecasts, future research should use predictive analytics and fine-tune the model granularity. The thesis demonstrates how design science can be applied for preparing specification of services but not only in software development. This work lays the groundwork for more extensive applications in digital twin technologies and energy optimization, in addition to contributing to our understanding of e-bus power management at Arlanda Airport.