利用MC/DC减少测试集大小的方法的研究

随着软件的发展，测试技术也在发展。MC／DC即修改条件／判定覆盖，是一种较新的结构覆盖准则，它是在C／DC（条件／判定覆盖）的基础上发展起来的。与其它结构覆盖准则相比，它只是线性地增加了测试用例的数量，使得软件测试更加具有可操作性。而对于测试来说，测试用例的选择和优化是至关重要的。在探讨MC／DC的基础上，利用MC／DC的特点，初步提出了利用MC／DC进行测试集减少的方法，使得减少后的测试集与原测试集对测试需求有着相同或相似的覆盖率，并对此方法的利弊做了一定的分析。     

面向故障定位的基于MC/DC的测试用例约简方法

对不断更新的软件进行回归测试时,持续增加的测试用例会造成累计测试用例数量庞大,进而影响测试成本。在故障定位领域,已有研究在考虑语句覆盖、路径覆盖等的基础上,提出了CMR&PVR等不同的测试用例约简方法。然而,这些方法在一定程度上影响了原始测试用例集的MC/DC(修订的条件/判定)覆盖率。提出一种以MC/DC覆盖为基础的综合测试用例约简方法MCDCR,利用该方法对原始测试用例集约简后,在确保原有故障定位准确性并保持较高约简比的同时,大幅提高了测试用例对程序的MC/DC覆盖率。采用Ochiai方法在Siemens 程序集上进行了实验及验证,结果表明MCDCR约简方法的综合效果明显优于已有的约简方法。     

基于二叉树满足MC/DC测试用例设计方法

软件测试是保证软件质量的有效方法,但测试工作过程繁琐,工作量较多。探索高效、可靠的测试用例设计方法一直是大家追求的目标,随着航空航天产品逻辑复杂性的提高及软件规模的日益增大,这种要求也变得更加迫切。依据MC/DC设计的测试用例既提高了测试用例设计的效率又增加了测试覆盖率,比较适合测试逻辑关系相对复杂的软件。当前的很多软件测试工具提供了软件测试覆盖率的判定功能,可以评定设计出的测试用例是否满足MC/DC的要求,而软件测试人员需要的是逆向的过程,论文提出应用唯一原因法和屏蔽法原理设计测试用例,可达到根据逻辑关系自动生成满足MC/DC要求测试用例的目的,提高了测试用例设计的效率。     

应用MC/DC准则时需考虑的问题及其改进方法

MC／DC(修订的条件／判定覆盖)准则是一种实用的软件结构覆盖率测试准则。目前,MC／DC在国际上已被广泛地应用于软件验证和测试过程中,在我国也被应用于一些软件项目中。介绍了MC／DC准则,提出了用此准则进行结构覆盖率分析时需注意的两个问题：结构覆盖率分析的问题和复杂逻辑语句的问题。最后,详细讨论了用MC／DC准则检查逻辑表达式错误时需考虑的3个方面及相应的改进方法,这3个方面包括逻辑式中操作符OR与XOR的误写、括号的位置不正确和逻辑组元被误写。     

Test criteria and coverage measures for software integration testing

The aim of this paper is to introduce a systematic approach to integration testing of software systems. Various test data selection criteria for integration testing are presented, coverage measures are introduced, and interconnection between them are discussed. The main principle is to transfer and adapt test criteria and coverage measures which are useful for unit testing to the level of integration testing. Test criteria help the tester to organise the test process. They should be chosen in accordance with the available test effort. Test coverage measures are defined as a ratio between the test cases required for satisfying the criteria and those of these which have been executed. The measures are used to obtain information about the completeness of integration tests. The approach is described for data flow and control flow oriented criteria and measures. The intention is to enable the tester to specify integration tests in advance in terms of effort, and to evaluate the results in terms of test completeness.     

Formal specification and testing: A case study

Z is a formal notation for writing system specifications that has been growing in popularity over recent years. This paper examines some of the issues involved in applying a ‘partition based’ testing method to a system specified in Z. Details of an extensive case study are given, from specification and implementation of the system to the development and execution of test cases. The strategy is found to have benefits compared to those based on less formal specifications, but there are limitations to the approach, and difficulties that need addressing.     

MC／DC最小测试用例集快速生成算法

以条件判定组合的语法树为研究对象,总结语法树的左右分支对判定结果的影响方式及结果,根据其影响特点提出超越语法树的快速生成改进判定／条件覆盖最小测试用例集的算法。与其他算法在在空间及时问方面进行比较,结果表明该算法具有一定的优越性。     

基于图的MC/DC 最小测试用例集快速生成算法

依针对MC／DC最4,N试用例集生成效率的问题,依据MC／DC准则,以条件判定组合的复杂逻辑关系为研究对象,采用将原始布尔表达式转化为语法树,再将语法树转化为图,分析图中节点对判定结果的影响的方法,研究了基于图快速生成最小测试用例集的算法．最后结合实倒对该算法进行了验证,并与其他算法进行了比较,结果表明该算法在手动和自动生成最小测试用例集时具有实用性和优越性．     

耦合条件的MC/DC测试用例集生成算法

MC/DC是一套航电A级软件的测试覆盖性准则,可以有效减少测试用例量.针对如何快速获取尽可能小的测试用例集这一难点展开研究,重点关注于具有耦合条件的逻辑表达式,提出了两套解决方案,分别用于解决零耦合/弱耦合条件和强耦合条件问题,并给出了示例证明.结果表明,灵活使用两套算法,可以全面解决一般逻辑表达式的MC/DC测试用例集的快速生成问题.     

Passive testing of communicating systems with timeouts

ContextThe design of complex systems demands methodologies to analyze its correct behaviour. It is usual that a correct behaviour is determined by the compliance with temporal requirements. Currently, testing is the most used technology to validate the correctness of systems. Although several techniques that take into account time aspects have been proposed, most of them require the tester interacts with the system. However, if this is not possible, it is necessary to apply a passive testing approach where the tester monitors the behaviour of the system.ObjectiveThe aim of this paper is to propose a methodology to perform passive testing on communicating systems in which the behaviour of their components must fulfill temporal restrictions associated with both performance and delays/timeouts.MethodOur framework uses algorithms for checking traces collected from the systems against invariants which formally represent the most relevant properties that must be fulfilled by the system. In order to support the feasibility of the methodology, we have performed an empirical study on a complex system for automatic recognition of images based on a pipeline architecture. We have analyzed the correctness of the system’s behaviour with respect to a set of invariants. Finally, an experiment, based on mutations of the system, was conducted to study the level of detection of a set of invariants.ResultsDifferent errors were detected and fixed along the development of the system by means of the proposed methodology. The results of the experiments with the mutated versions of the system indicated that the designed set of invariants was more effective in finding errors associated to temporal aspects than those related to communication among components.ConclusionThe proposed technique has been shown to be very useful for analyzing complex timed systems, and find errors when the tester has no control over their behaviour.     

A binomial software reliability model based on coverage of structural testing criteria

A new approach to software reliability modeling is discussed where variables indirectly related with software reliability are used to provide additional information for the modeling process. Previous studies, empirical and theoretical evidences, and results from experiments indicate that there is a strong relationship between software reliability and coverage of program elements required to be exercised by structural testing criteria. This paper develops a binomial type coverage-based software reliability model through the definition of a coverage-based failure rate function. The Binomial software reliability Model Based on Coverage—BMBC—is proposed and discussed. In the BMBC test data between failures is used instead of time as independent variable; the model was assessed with test data from a real application, making use of the following structural testing criteria: all-nodes, all-edges, and potential-uses—a data-flow based family of testing criteria. The results from our experiments have shown that our modeling approach has some advantages over some traditional reliability models and points to a very promising research direction in software reliability.

MC/DC 最小测试用例集递归分块矩阵生成算法

测试用例个数可以影响软件测试的成本与效率,因此最小测试用例集的生成算法具有重要的实用价值。对布尔表达式语法树采用递归分块矩阵处理,得到了MC/DC最小测试用例集生成算法。并证明了该算法的正确性,给出其成立的前提条件。     

The formalization and analysis of a communications protocol

The MSMIE protocol [SBC89] allows processors in a distributed system to communicate via shared memory. It was designed to meet the reliability and efficiency needs of applications such as nuclear safety systems. We present a formal model of the MSMIE protocol expressed in the notation CCS. Desirable properties of the protocol are expressed in the modal mu-calculus, an expressive modal logic. We show that the protocol lacks an important liveness property. In actual operation, additional operating constraints are checked to avoid potential problems. We present a modified protocol and show that it possesses the liveness property even without checking operating constraints. We also show how parts of the analysis were automated with the Concurrency Workbench.     

燃料电池车载大功率DC/DC变换器的设计与应用

燃料电池的输出特性偏软,电压偏低,难以直接与电动机驱动器匹配,采用DC/DC变换器改善其输出特性,提高输出电压,将燃料电池转换成稳定可控的直流电源,变换器所处的电磁环境较为恶劣,电磁干扰因素居多,采用Motorola(Freescale)16位车用微控制器MC9S12D64作为DC/DC的控制单元,使DC/DC具有良好的抗干扰性能和可靠的运行性能。     

On the adoption of MC/DC and control-flow adequacy for a tight integration of program testing and statistical fault localization

ContextTesting and debugging consume a significant portion of software development effort. Both processes are usually conducted independently despite their close relationship with each other. Test adequacy is vital for developers to assure that sufficient testing effort has been made, while finding all the faults in a program as soon as possible is equally important. A tight integration between testing and debugging activities is essential.ObjectiveThe paper aims at finding whether three factors, namely, the adequacy criterion to gauge a test suite, the size of a prioritized test suite, and the percentage of such a test suite used in fault localization, have significant impacts on integrating test case prioritization techniques with statistical fault localization techniques.MethodWe conduct a controlled experiment to investigate the effectiveness of applying adequate test suites to locate faults in a benchmark suite of seven Siemens programs and four real-life UNIX utility programs using three adequacy criteria, 16 test case prioritization techniques, and four statistical fault localization techniques. We measure the proportion of code needed to be examined in order to locate a fault as the effectiveness of statistical fault localization techniques. We also investigate the integration of test case prioritization and statistical fault localization with postmortem analysis.ResultThe main result shows that on average, it is more effective for a statistical fault localization technique to utilize the execution results of a MC/DC-adequate test suite than those of a branch-adequate test suite, and is in turn more effective to utilize the execution results of a branch-adequate test suite than those of a statement-adequate test suite. On the other hand, we find that none of the fault localization techniques studied can be sufficiently effective in suggesting fault-relevant statements that can fit easily into one debug window of a typical IDE.ConclusionWe find that the adequacy criterion and the percentage of a prioritized test suite utilized are major factors affecting the effectiveness of statistical fault localization techniques. In our experiment, the adoption of a stronger adequacy criterion can lead to more effective integration of testing and debugging.     

Using symbolic execution and data flow criteria to aid test data selection

The utilization is described of a data flow path selection criterion in a symbolic execution system. The system automatically generates a subset of program paths according to a certain control flow criterion. This subset is called the ZOT-subset, since it requires paths that traverse loops zero, one and two times. Experience indicates that traversing this subset of program paths is enough to cover most control flow and data flow components of the program. The problem with the ZOT-subset is that it might contain, for large programs, a large number of paths. The number of paths in this subset can be reduced by concentrating on executable paths that cover vital components of programs such as data flow components. This object is achieved by employing a data flow path selection criterion in the system. The system symbolically executes the paths of the ZOT-subset, and creates a system of branch conditions for each one. The user determines infeasible paths by checking the consistency of each system of conditions. The system selects feasible paths from the ZOT-subset that cover the data flow criterion. Solving the systems of conditions of the selected paths provides the user with test data to fulfil the given data flow criterion.     

Defining a test coverage criterion for model-level testing of FBD programs

ContextThe Programmable Logic Controller (PLC) is being integrated into the automation and control of computer systems in safety–critical domains at an increasing rate. Thoroughly testing such software to ensure safety is crucial. Function Block Diagram (FBD) is a popular data-flow programming language for PLC. Current practice often involves translating an FBD program into an equivalent C program for testing. Little research has been conducted on coverage of direct testing a data-flow program, such as an FBD program, at the model level. There are no commonly accepted structural test coverage criteria for data-flow programs. The objective of this study is to develop effective structural test coverage criterion for testing model-level FBD programs. The proposed testing scheme can be used to detect mutation errors at the logical function level.ObjectiveThe purpose of this study is to design a new test coverage criterion that can directly test FBD programs and effectively detect logical function mutation errors.MethodA complete test set for each function and function block in an FBD program are defined. Moreover, this method augments the data-flow path concept with a sensitivity check to avoid fault masking and effectively detect logical function mutation errors.ResultsPreliminary experiments show that this test coverage criterion is comprehensive and effective for error detection.ConclusionThe proposed coverage criterion is general and can be applied to real cases to improve the quality of data-flow program design.     

一种反激式双输出DC/DC变换器的设计与实现

针对市场上DC/DC开关电源高压输出时,输出电压纹波较大问题,介绍了一种±50 V双输出DC/DC开关电源的设计方法及测试结果。该电路采用电流控制型PWM控制芯片,工作于反激模式。输入输出通过光耦实现隔离。该DC/DC变换器具有带负载能力强、纹波低、输出电压高等特点,可为电子设备提供稳定的供电电压。     

交错并联双向DC/DC变换器小信号模型分析

非隔离型双向DC/DC变换器广泛的应用于混合直流供电系统中,在低电压大电流的场合采用交错并联拓扑结构的双向DC/DC变换器具有显著的优势。基于超级电容与蓄电池的混合储能系统,采用状态空间平均法,以三通道交错并联Buck/Boost变换器在Buck模态的工作状态作为模型进行分析,推导出相电感电流连续模式(CCM模态)下的交流小信号状态方程及其等效模型,并得到了电路模型的开环传递函数。通过Matlab仿真得到整个系统开环幅频和相频特性曲线,并以此为依据优化设计控制器的补偿网络,提高了系统的稳定性和瞬态响应速度,最后进行实验验证,结果表明双闭环的控制策略实现了恒压限流且动态特性较好。