Estimating the feasibility of transition paths in extended finite state machines

There has been significant interest in automating testing on the basis of an extended finite state machine (EFSM) model of the required behaviour of the implementation under test (IUT). Many test criteria require that certain parts of the EFSM are executed. For example, we may want to execute every transition of the EFSM. In order to find a test suite (set of input sequences) that achieves this we might first derive a set of paths through the EFSM that satisfy the criterion using, for example, algorithms from graph theory. We then attempt to produce input sequences that trigger these paths. Unfortunately, however, the EFSM might have infeasible paths and the problem of determining whether a path is feasible is generally undecidable. This paper describes an approach in which a fitness function is used to estimate how easy it is to find an input sequence to trigger a given path through an EFSM. Such a fitness function could be used in a search-based approach in which we search for a path with good fitness that achieves a test objective, such as executing a particular transition, and then search for an input sequence that triggers the path. If this second search fails then we search for another path with good fitness and repeat the process. We give a computationally inexpensive approach (fitness function) that estimates the feasibility of a path. In order to evaluate this fitness function we compared the fitness of a path with the ease with which an input sequence can be produced using search to trigger the path and we used random sampling in order to estimate this. The empirical evidence suggests that a reasonably good correlation (0.72 and 0.62) exists between the fitness of a path, produced using the proposed fitness function, and an estimate of the ease with which we can randomly generate an input sequence to trigger the path

Constraint-Based Heuristic On-line Test Generation from Non-deterministic I/O EFSMs

We are investigating on-line model-based test generation from non-deterministic output-observable Input/Output Extended Finite State Machine (I/O EFSM) models of Systems Under Test (SUTs). We propose a novel constraint-based heuristic approach (Heuristic Reactive Planning Tester (xRPT)) for on-line conformance testing non-deterministic SUTs. An indicative feature of xRPT is the capability of making reasonable decisions for achieving the test goals in the on-line testing process by using the results of off-line bounded static reachability analysis based on the SUT model and test goal specification. We present xRPT in detail and make performance comparison with other existing search strategies and approaches on examples with varying complexity.Comment: In Proceedings MBT 2012, arXiv:1202.582

An integrated search-based approach for automatic testing from extended finite state machine (EFSM) models

This is the post-print version of the Article - Copyright @ 2011 ElsevierThe extended finite state machine (EFSM) is a modelling approach that has been used to represent a wide range of systems. When testing from an EFSM, it is normal to use a test criterion such as transition coverage. Such test criteria are often expressed in terms of transition paths (TPs) through an EFSM. Despite the popularity of EFSMs, testing from an EFSM is difficult for two main reasons: path feasibility and path input sequence generation. The path feasibility problem concerns generating paths that are feasible whereas the path input sequence generation problem is to find an input sequence that can traverse a feasible path. While search-based approaches have been used in test automation, there has been relatively little work that uses them when testing from an EFSM. In this paper, we propose an integrated search-based approach to automate testing from an EFSM. The approach has two phases, the aim of the first phase being to produce a feasible TP (FTP) while the second phase searches for an input sequence to trigger this TP. The first phase uses a Genetic Algorithm whose fitness function is a TP feasibility metric based on dataflow dependence. The second phase uses a Genetic Algorithm whose fitness function is based on a combination of a branch distance function and approach level. Experimental results using five EFSMs found the first phase to be effective in generating FTPs with a success rate of approximately 96.6%. Furthermore, the proposed input sequence generator could trigger all the generated feasible TPs (success rate = 100%). The results derived from the experiment demonstrate that the proposed approach is effective in automating testing from an EFSM

Search-based software engineering: A search-based approach for testing from extended finite state machine (EFSM) models

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The extended finite state machine (EFSM) is a powerful modelling approach that has been applied to represent a wide range of systems. Despite its popularity, testing from an EFSM is a substantial problem for two main reasons: path feasibility and path test case generation. The path feasibility problem concerns generating transition paths through an EFSM that are feasible and satisfy a given test criterion. In an EFSM, guards and assignments in a path‟s transitions may cause some selected paths to be infeasible. The problem of path test case generation is to find a sequence of inputs that can exercise the transitions in a given feasible path. However, the transitions‟ guards and assignments in a given path can impose difficulties when producing such data making the range of acceptable inputs narrowed down to a possibly tiny range. While search-based approaches have proven efficient in automating aspects of testing, these have received little attention when testing from EFSMs. This thesis proposes an integrated search-based approach to automatically test from an EFSM. The proposed approach generates paths through an EFSM that are potentially feasible and satisfy a test criterion. Then, it generates test cases that can exercise the generated feasible paths. The approach is evaluated by being used to test from five EFSM cases studies. The achieved experimental results demonstrate the value of the proposed approach.Aleppo University, Syri

A multi-objective evolutionary approach for automatic generation of test cases from state machines

Orientador: Eliane MartinsTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: A geração automática de casos de teste contribui tanto para melhorar a produtividade quanto para reduzir esforço e custo no processo de desenvolvimento de software. Neste trabalho é proposta uma abordagem, denominada MOST (Multi-Objective Search-based Testing approach from EFSM), para gerar casos de teste a partir de Máquina de Estados Finitos Estendida (MEFE) com a aplicação de uma técnica de otimização. No teste baseado em MEFE, é necessário encontrar uma sequência de entrada para exercitar um caminho no modelo, a fim de cobrir um critério de teste (e.g. todas as transições). Como as sequências podem ter diferentes tamanhos, motivou-se o desenvolvimento do algoritmo M-GEOvsl (Multi-Objective Generalized Extremal Optimization with variable string length) que permite gerar soluções de diferentes tamanhos. Além disso, por ser um algoritmo multiobjetivo, M-GEOvsl também possibilita que mais de um critério seja usado para avaliar as soluções. Com a aplicação desse algoritmo em MOST, tanto a cobertura da transição alvo quanto o tamanho da sequência são levados em consideração na geração de casos de teste. Para guiar a busca, são utilizadas informações das dependências do modelo. O algoritmo gera as sequências de entrada, incluindo os valores de seus parâmetros. Em MOST, um modelo executável da MEFE recebe como entrada os dados gerados pelo M-GEOvsl e produz dinamicamente os caminhos percorridos. Uma vez que os aspectos de controle e dados do modelo são considerados durante a execução do modelo, evita-se o problema de geração de caminhos infactíveis. Um caminho pode ser sintaticamente possível, mas semanticamente infactível, devido aos conitos de dados envolvidos no modelo. Para avaliar a abordagem proposta foram realizados vários experimentos com modelos da literatura e de aplicações reais. Os resultados da abordagem também foram comparados com os casos de teste obtidos em um trabalho relacionado.Abstract: Automated test case generation can improve the productivity as well as reduce effort and cost in the software development process. In this work an approach, named MOST (Multi- Objective Search-based Testing approach from EFSM), is proposed to generate test cases from Extended Finite State Machine (EFSM) using an optimization technique. In EFSM based testing, an input sequence should be found to sensitize a path in the model, in order to cover a test criterion (e.g. all transitions). As the sequences can have different lengths, it motivates the development of the M-GEOvsl (Multi-Objective Generalized Extremal Optimization with variable string length) algorithm that makes possible the generation of solutions with different lengths. Moreover, as a multiobjective algorithm, M-GEOvsl also allows to use more than one criterion to evaluate the solutions. Using this algorithm in MOST, the coverage of the target transition as well as the sequence length are taken into account in the test case generation. To guide the search, the information about the model dependences is used. The algorithm generates the input sequences, including the values of their parameters. In MOST, an executable model of the EFSM receives as input the data generated by M-GEOvsl and produces the traversed paths dynamically. Since the control and data aspects are considered during model execution, the problem of infeasible path generation is avoided. A path can be syntatically possible, but semantically infeasible, due to the data conicts in the model. In order to evaluate the proposed approach, experiments were performed with models of the literature and real-world applications. The results were also compared to the test cases obtained in a related workDoutoradoCiência da ComputaçãoDoutor em Ciência da Computaçã

Fail-Safe Testing of Safety-Critical Systems

This dissertation proposes an approach for testing of safety-critical systems. It is based on a behavioral and a fault model. The two models are analyzed for compatibility and necessary changes are identified to make them compatible. Then transformation rules are used to transform the fault model into the same model type as the behavioral model. Integration rules define how to combine them. This approach results in an integrated model which then can be used to generate tests using a variety of testing criteria. The dissertation illustrates this general framework using a CEFSM for the behavioral model and a Fault Tree for the fault model. We apply the technique to a variety of applications such as a Gas burner, an Aerospace Launch System, and a Railroad Crossing Control System. We also investigate the scalability of the approach and compare its efficiency with integrating a state chart and a fault tree. Construction and Analysis of Distributed Processes (CADP) has been used as a supporting tool for this approach to generate test cases from the integrated model and to analyze the integrated model for some properties such as deadlock and livelock

Search-based software engineering : a search-based approach for testing from extended finite state machine (EFSM) models

The extended finite state machine (EFSM) is a powerful modelling approach that has been applied to represent a wide range of systems. Despite its popularity, testing from an EFSM is a substantial problem for two main reasons: path feasibility and path test case generation. The path feasibility problem concerns generating transition paths through an EFSM that are feasible and satisfy a given test criterion. In an EFSM, guards and assignments in a path‟s transitions may cause some selected paths to be infeasible. The problem of path test case generation is to find a sequence of inputs that can exercise the transitions in a given feasible path. However, the transitions‟ guards and assignments in a given path can impose difficulties when producing such data making the range of acceptable inputs narrowed down to a possibly tiny range. While search-based approaches have proven efficient in automating aspects of testing, these have received little attention when testing from EFSMs. This thesis proposes an integrated search-based approach to automatically test from an EFSM. The proposed approach generates paths through an EFSM that are potentially feasible and satisfy a test criterion. Then, it generates test cases that can exercise the generated feasible paths. The approach is evaluated by being used to test from five EFSM cases studies. The achieved experimental results demonstrate the value of the proposed approach.EThOS - Electronic Theses Online ServiceAleppo University, SyriaGBUnited Kingdo