Wilkerson de L. Andrade

LTS-BT: a tool to generate and select functional test cases for embedded systems

Automation of model-based testing for embedded systems is discussed. The focus is on feature and feature interruption test case generation and selection from behavioral specifications. For this, the LTS-BT tool is presented. The tool has been designed to suit embedded systems by focusing on selected notations for behavior specification and tailored techniques for test case generation and selection. This is motivated by the particularities of these systems that challenge cost-effective testing.

Generating interaction test cases for mobile phone systems from use case specifications

The mobile phone market has become even more competitive, demanding high quality standards. In this context, applications are built as sets of functionalities, called features. Such features are combined in use scenarios of the application. Due to the fact that the features are usually developed in isolation, the tests of their interactions in such scenarios are compromised. In this paper, we present a proposal of specifying feature interaction requirements with use cases; generating a behavioral model from such specification; and a strategy for generating test cases from the behavioral model that aims to extract feature interaction scenarios in such a way that interactions can be tested.

Abstracting Time and Data for Conformance Testing of Real-Time Systems

Current approaches to model-based conformance testing of real-time systems are mostly based either on finite state machines/transition systems or on timed automata. However, most real-time systems manipulate data while being subject to time constraints. The usual solution consists in enumerating data values (in finite domains) while treating time symbolically, thus leading to the classical state explosion problem. This paper proposes a new model of real-time systems as an extension of both symbolic transition systems and timed automata, in order to handle both data and time requirements symbolically. We then adapt the tioco conformance testing theory to deal with this model and describe a test case generation process based on a combination of symbolic execution and constraint solving for the data part and symbolic analysis for timed aspects.

Generating Test Cases for Real-Time Systems Based on Symbolic Models

The state space explosion problem is one of the challenges to be faced by test case generation techniques, particularly when data values need to be enumerated. This problem gets even worse for real-time systems (RTS) that also have time constraints. The usual solution in this context, based on finite state machines or time automata, consists of enumerating data values (restricted to finite domains) while treating time symbolically. In this paper, a symbolic model for conformance testing of real-time systems software named TIOSTS that addresses both data and time symbolically is presented. Moreover, a test case generation process is defined to select more general test cases with variables and parameters that can be instantiated at testing execution time. Generation is based on a combination of symbolic execution and constraint solving for the data part and symbolic analysis for timed aspects. Furthermore, the practical application of the process is investigated through a case study.

Test Case Generation of Embedded Real-Time Systems with Interruptions for FreeRTOS

This paper discusses issues raised in the construction of test models and automatic generation of test cases for embedded real-time systems with interruptions that can run on the FreeRTOS operating system. The focus is on the use of symbolic transition systems (STSs) as the formalism from which test cases are generated by using the STG tool. The solution presented considers a test case execution model for real-time systems with interruptions that can be based on the integrated use of FreeRTOS components. A case study is presented to illustrate all steps from the construction of the test model to test case generation.

Testing interruptions in reactive systems

Modelling and testing of reactive systems with interruptions are discussed. These systems are commonly found in portable devices, where interruptions to a running application can be demanded at any time, due to concurrent execution of processes sharing a single resource, such as screen, as well as arrival of calls from network distributed services. Since the possible number of combinations of allowed interruptions is large, proper test case selection activities need to be performed. But, in order to systematically investigate and select test cases, it is fundamental to explicitly model interruption behaviour in a compositional way, avoiding the need for explicit enumeration. This work presents a strategy for testing interruptions in reactive systems that covers modelling for testing of systems with interruptions, generation and selection of sound test cases. The strategy is supported by the LTS-BT tool. Moreover, a formal model of an environment devoted to execution of test cases with interruptions is presented. Finally, a case study illustrates its applicability in the mobile phone application domain.

A systematic mapping study on assessing computational thinking abilities

Several initiatives have been created to promote Computational Thinking (CT) abilities in students. There are multiple approaches of assessing CT and wide abilities and skills involved. However, the evidence on how to assess CT has not yet been systematically grouped or reviewed. The goal of our study is to identify and classify approaches to promote CT and the different ways of assessing CT abilities. To achieve this goal, a systematic mapping study was planned and executed. The results reveal that: (i) programming courses are the most common pedagogical approaches to promote CT for K-12 students; (ii) multiple skills are involved in CT, but solving problems, algorithms, and abstraction are most common abilities assessed; and (iii) codes and multi-choice questionnaires are the most common artifacts for assessing CT abilities. This study points out to the fact that there are open questions for exploring and developing new researches for promoting and assessing CT abilities.

Towards a requirements traceability process centered on the traceability model

Requirements traceability (RT) has been acknowledged as a valuable activity in the software development process. Its importance is reflected in different quality standards, which dictates that requirements should be traceable through the software development life-cycle. However, there is not a consensus about the traceability process and, as a consequence, RT practices cannot be unified across different organizational settings. Identifying common aspects to the RT process has been recognized as one of the grand challenges of RT. Even though, researches regarding improvements in requirements engineering (RE) neglect the traceability research scope. Therefore, is this paper, we propose and detail a RT process, specifying its workflow, actors, responsibilities and inputs/outputs as well as establishing contracts that govern the proposed process phases. To evaluate the proposed process, we have conducted an empirical experiment in a real project under development for the federal police of Brazil. We observed time, precision, recall and efficiency metrics and concluded that the proposed process improves the performance of RT practices. As a final remark, the proposed process contributes towards the discussion of common aspects of the RT process.

Interruption Testing of Reactive Systems

Reactive systems may be composed of a number of concurrent processes and network distributed services, where interruptions in a flow of execution can occur at any time. These systems are very difficult to test. One of the reasons is that the possible number of combinations of allowed interruptions at different points of a flow of execution is huge. This makes exhaustive specification of each possibility infeasible. Without a specification, automated test case generation and selection is compromised. This work presents a strategy for testing interruptions in reactive systems that covers modelling (devoted to testing) of systems with interruptions, generation and selection of sound test cases. The strategy is supported by the LTS-BT tool. A case study is presented to illustrate its applicability in the mobile phone application domain.

The Oracle Problem for Testing against Quantified Properties

The oracle problem for testing from quantified properties is discussed and illustrated by proposed solutions for first-order logic and computation tree logic (CTL) properties. Unless constraints are placed, it is not always possible to generate feasible test suites from which accurate conclusions on their execution results can be reached regarding conformity with the intended property.