An Investigation into Improving Test Effectiveness for Embedded Software

This thesis reports on the investigation of the effectiveness of software testing on embedded systems. The aim was to improve confidence in the current methods employed or to find new methods which could improve the hit rate of defects found before software is sent to a customer. We investigate previous work into software testing effectives and various black box testing methods. There are various Black Box testing methodologies that can be employed to detect errors in systems with varying degrees of success. In this thesis we investigate the transformation of the white box testing technique of Definition Use (DU) Path testing using a RESOLVE like specification, to be applied as black box test method. We do not use RESOLVE it self, instead we defined our own method of automatic test generation based on the principles of RESOLVE. Then we compare this method to more commonly used requirements driven test selection, and pure boundary value analysis (BVA) testing techniques. The results reported in this thesis indicate that BVA and DU test selection methods create tests that are covered by unit and integration tests. The current requirements driven test cases create tests with a combination of features working in tandem. It was found that combination of features was more likely to find defects because developers tests had a lesser focus on this area. The tests generated by the BVA and DU test selection methods did not find any defects that their respective methods were intended to find. This is due to the development team already having tests that covered these areas and defects had been fixed before system tests could be run. Based on the fact that the current test selection methods find defects and the methods we investigated do not, this adds confidence that the system test approach to testing is effective. The investigation of defects found showed that timing related errors are common and that a test selection method designed to find timing related defects would be worth investigating. The investigation also revealed a useful method in automatic generation of test cases. The RESOLVE like specification was used to apply a DU testing as a black box test method. This method showed to be more time efficient at generating test cases than the existing requirements driven approach. Although the test cases did not reveal significant defects, due to the overlap with integration testing, it could be a useful method for developers to generate test cases

Integration modes, global networks, and knowledge diffusion in overseas M&As by emerging market firms

Purpose This paper aims to examine how integration modes impact the acquirer knowledge diffusion capacity of overseas mergers and acquisitions (M&As) effected by emerging market firms and the role played by the global innovation network position of the acquiring firms in affecting this relationship. Design/methodology/approach Through the use of structural equation modelling and bootstrap testing, the hypotheses are tested by drawing upon a sample of 102 overseas M&As effected by listed Chinese manufacturing companies. Findings The results show that acquirers from emerging countries are unable to increase the knowledge diffusion capacity unless they choose the right post-merger integration mode. This paper also finds that the relationship between integration mode and knowledge diffusion is channelled through the centrality and structural holes of acquirers in the global innovation networks. When considering the combinations of different resource similarities and complementarities of the acquired firms, differences emerge in the integration model and network embedded path of acquirers in emerging countries. Practical implications Emerging market multinational enterprises should consider post-merger integration as a crucial facilitator to the crafting of global innovation network positions that promote knowledge diffusion. The choices of integration mode and brand management autonomy should be matched with the resource similarities and complementarities that exist between the acquirer and target firms. Originality/value Based on the resource orchestration theory and by focussing on network centrality and structural hole as the crucial links, this study provides a nuanced understanding of the relationship between post-merger integration and knowledge diffusion and sheds light on latecomer firms from emerging countries

Integrating testing techniques through process programming

Integration of multiple testing techniques is required to demonstrate high quality of software. Technique integration has three basic goals: incremental testing capabilities, extensive error detection, and cost-effective application. We are experimenting with the use of process programming as a mechanism of integrating testing techniques. Having set out to integrate DATA FLOW testing and RELAY, we proposed synergistic use of these techniques to achieve all three goals. We developed a testing process program much as we would develop a software product from requirements through design to implementation and evaluation. We found process programming to be effective for explicitly integrating the techniques and achieving the desired synergism. Used in this way, process programming also mitigates many of the other problems that plague testing in the software development process

Software integration testing based on communication coverage criteria and partial model generation

This paper considers the problem of integration testing the components of a timed distributed software system. We assume that communication between the components is specified using timed interface automata and use computational tree logic (CTL) to define communication-based coverage criteria that refer to send- and receive-statements and communication paths. The proposed method enables testers to focus during component integration on such parts of the specification, e.g. behaviour specifications or Markovian usage models, that are involved in the communication between components to be integrated. A more specific application area of this approach is the integration of test-models, e.g. a transmission gear can be tested based on separated models for the driver behaviour, the engine condition, and the mechanical and hydraulical transmission states. Given such a state-based specification of a distributed system and a concrete coverage goal, a model checker is used in order to determine the coverage or generate test sequences that achieve the goal. Given the generated test sequences we derive a partial test-model of the components from which the test sequences are derived. The partial model can be used to drive further testing and can also be used as the basis for producing additional partial models in incremental integration testing. While the process of deriving the test sequences could suffer from a combinatorial explosion, the effort required to generate the partial model is polynomial in the number of test sequences and their length. Thus, where it is not feasible to produce test sequences that achieve a given type of coverage it is still possible to produce a partial model on the basis of test sequences generated to achieve some other criterion. As a result, the process of generating a partial model has the potential to scale to large industrial software systems. While a particular model checker, UPPAAL, was used, it should be relatively straightforward to adapt the approach for use with other CTL based model checkers. A potential additional benefit of the approach is that it provides a visual description of the state-based testing of distributed systems, which may be beneficial in other contexts such as education and comprehension

Fault-based regression testing in a reactive environment

Regression testing is the process of retesting software after modification. Regression testing is a major factor contributing to the high cost of software maintenance. To control this cost, regression testing must be accomplished efficiently through effective reuse of test cases and judicious generation of new test cases.Fault-based testing focuses on the detection of particular classes of faults. RELAY is a fault-based testing technique that guarantees the detection of errors caused by any fault in a chosen fault classification. RELAY can be used as a regression testing technique to generate the test cases required to demonstrate that a modification is properly made. In addition, the information related to a test case chosen to detect a potential fault guides in choosing previously-selected test cases that should be reused, for a given modification.This paper presents the concepts behind RELAY and discusses how RELAY could be used as a regression testing technique. It also describes a testing environment that supports reactive regression testing as well as testing throughout the development lifecycle, which is based on integrating the RELAY model with other testing techniques

AFTI/F-16 digital flight control system experience

The Advanced Flighter Technology Integration (AFTI) F-16 program is investigating the integration of emerging technologies into an advanced fighter aircraft. The three major technologies involved are the triplex digital flight control system; decoupled aircraft flight control; and integration of avionics, pilot displays, and flight control. In addition to investigating improvements in fighter performance, the AFTI/F-16 program provides a look at generic problems facing highly integrated, flight-crucial digital controls. An overview of the AFTI/F-16 systems is followed by a summary of flight test experience and recommendations

An Adaptive Design Methodology for Reduction of Product Development Risk

Embedded systems interaction with environment inherently complicates understanding of requirements and their correct implementation. However, product uncertainty is highest during early stages of development. Design verification is an essential step in the development of any system, especially for Embedded System. This paper introduces a novel adaptive design methodology, which incorporates step-wise prototyping and verification. With each adaptive step product-realization level is enhanced while decreasing the level of product uncertainty, thereby reducing the overall costs. The back-bone of this frame-work is the development of Domain Specific Operational (DOP) Model and the associated Verification Instrumentation for Test and Evaluation, developed based on the DOP model. Together they generate functionally valid test-sequence for carrying out prototype evaluation. With the help of a case study 'Multimode Detection Subsystem' the application of this method is sketched. The design methodologies can be compared by defining and computing a generic performance criterion like Average design-cycle Risk. For the case study, by computing Average design-cycle Risk, it is shown that the adaptive method reduces the product development risk for a small increase in the total design cycle time.Comment: 21 pages, 9 figure