Model checkers software testing

This is typically associated with hardware or software systems, where the specification contains liveness requirements such as avoidance of livelock as well as safety requirements such as avoidance of states representing. Model checking techniques have been proven to be an excellent approach to analyse critical properties of complex systems. In recent years, automated testcase generation with modelcheckers has seen increasing attention in the research community. A comparative study of software model checkers as unit. Black, issues in software testing with model checkers preprint, submitted to 2003 international conference on dependable systems and networks dsn 2003, san francisco, california, june 2225, 2003. Test generation using model checking department of computer. Bugfinding capabilities i s aflfuzz t tiger t crestppc l t e t test t cbmc m aseq m cr m d m s mc l total found 1490 605 57 376 236 826 292 830 889 949 844 887 1092 1176 compilable 1115 605 57 376 236 826 292 779 819 830 761 887 930 1014 median cpu time s 11 4. Regression testing and testsuite update with modelcheckers gordon fraser 1,2, bernhard k.

Model based testing is an application of model based design for designing and optionally also executing artifacts to perform software testing or system testing. About a decade after the initial proposal to use model checkers for the generation of test cases we take a look at the results in this field of research. Indeed, several drawbacks result from the use of model checkers for test case generation. Although model checkers can be used to generate tests 3, 5, existing methods allow the model checker. Finding and understanding bugs in software model checkers. Improving modelcheckers for software testing abstract. Generating a short, but effective test suite usually needs a lot ofmanual work and expert knowledge. Test criteria are expressed as temporal properties. This paper presents a new methodology to extend explicit model checkers for hybrid systems analysis. The use of model checkers for testing offers full automation, a choice of different methods to derive test suites, and is efficient under certain preconditions. Autogenerating test sequences using model checkers. Black, wei ding nistir 6777, national institute of standards and technology, 2002 the primary focus of formal methods is static analysis of specifications and code, but there is also a long tradition of exploiting formal methods for testing. Model checkers were originally developed to check that state machines conformed to specifications.

This paper continues this tradition by exploring the role of model checkers in software testing. Testing is an essential, but time and resource consuming activity in the software development process. We describe two modeling methods for specificationbased mutation testing using model checkers that guarantee this propagation. Normally, these counterexamples are meant to guide an analyst when searching for the root cause of a property violation. We show how to apply these powerful computation engines to the problems of test generation and test evaluation for a variety. In computer science, model checking or property checking is a method for checking whether a finitestate model of a system meets a given specification a. Software testing is necessary because verification is often infeasible. Stateless model checking is a useful statespace exploration technique for systematically testing complex realworld software. For example, a model checker can report a test whenever it finds an interesting state, i. Using modelcheckers to generate and analyze property. Instead of using formal methods, developers test software. Software model checking is the algorithmic analysis of programs to prove. However, little work exists on validating software model checkers, an important problem.

Software model checking smc is a wellknown automatic program verification technique and frequently adopted for checking safetycritical software. Model checkers in software testing by paul ammann, paul e. Model checkers were originally developed to check that state machines conformed to specifications expressed in a temporal logic. Extending model checkers for hybrid system verification. Model checkers article about model checkers by the free. The model is usually expressed as a directed graph consisting of nodes or vertices and edges. Software model checkers are becoming increasingly popular to assist in the automation of software testing. Section 3 defines a formal framework suitable for model checking in which we can discuss the coverage of various software engineering artifacts. Model checkers are tools that systematically explore the state space of a model to demonstrate the presence of errors or to confirm their absence. The approach analyzes both these specification models to generate test cases that are then converted into temporal logic formulae to be model checked on the. Verification is applied to software as a proof method with respect to its requirements. Evaluating model testing and model checking for finding requirements violations in simulink models. The ieee software engineering body of knowledge swebok 2004 defines testing as an activity performed for evaluating product quality, and for improving it, by identifying defects and problems bourque and dupuis 2004. The picture on the right depicts the former approach.

We claim that the answer is no, and show with experiments on a large benchmark of c programs that software model checkers even find more bugs than testers. However, automated software testing is commonly used to ensure confidence in the conformance of an. Model checking is a lightweight formal method to check the truth \or falsity\ of statements. Various approaches to model checking software 6 hypothesis model checking is an algorithmic approach to analysis of finitestate systems model checking has been originally developed for analysis of hardware designs and communication protocols model checking algorithms and tools have to be tuned to be applicable to analysis of software.

We discuss a couple techniques that alter the specification to force the model checker to output counterexamples that are then used as test cases for the software. The model based approach to software testing encompasses the creation of an abstract model. The counterexamples generated by model checkers are often better for localizing and correcting failures than discovering failures from testing and simulation because they tend to be very short under 10 input. Aichernig 3 and franz wotawa 4 institute for software technology graz university of technology inffeldgasse 16b2 a8010 graz, austria abstract several modelchecker based methods to automated testcase generation have been proposed. Whereas conventional model checkers require manual effort to create an abstract target model, modern software model checkers remove this overhead by directly analyzing a target c program, and can be utilized as unit testing tools. Automation is desirable since the complexity and the effort involved are significant. Abstract the primary focus of formal methods is static analysis of specifications and code, but there is also a long tradition of exploiting formal methods for testing. The modelbased approach to software testing encompasses the creation of an abstract model. Explains effective use of model checking to generate complete test cases. The primary focus of formal methods is static analysis of specifications and code, but there is also a long tradition of exploiting formal methods for testing. Model checkers in software testing microform, 2002. Testing with model checkers is a modelbased testing technique.

The model checker then checks that the state model conforms to certain behavioral properties. Property relevant software testing with modelcheckers. This paper continues this model by exploring the role of model checkers in software testing. Our experience with nonfilesystem flight software modules shows that methods even further removed from traditional static formal methods can be assisted by formal approaches, yet readily adopted by test engineers and. A state model is an abstract state machine that can be in one of various states. Issues in software component testing 1998 citeseerx.

These approaches leverage the witness or counterexample generation capability of modelcheckers for constructing test cases. Model checkers generate a state model from your code. Despite the large volume of academic research on software testing and verification, there are relatively. In recent years, automated test case generation with model checkers has seen increasing attention in the research community. The use of modelcheckers for testing offers full automation, a choice of different methods to derive testsuites, and is efficient under certain preconditions. Testing with model checkers is mostly applied to reactive systems 4, where the software size is within bounds e. Verification and test methods for access control policies. However, realistic concurrent programs are nonterminating, a property that signi. Coverage based testcase generation using model checkers. In contrast to static analysis techniques, testing requires the execution of the program with specific input values to find.

The nodes represents states of a program, the edges represent possible. Issues in using model checkers for test case generation. Integration of formal analysis into a modelbased software. Testcase generation with modelcheckers is apromising. In modelbased testing, testcases are created for an iut with respect to a model m and a speci. Automated testing automated combinatorial testing for. Most software developers consider formal methods too hard and tedious to use in practice. Evaluating model testing and model checking for finding. If model checkers were designed or adapted to take into account the needs that result from the application to software testing, this could lead to significant improvements with regard to test suite quality and performance. Home browse by title proceedings qsic 07 improving modelcheckers for software testing. However, since software model checkers are not fully mature yet, they have limitations according to the underlying. Model checkers are formal verification tools, capable of providing counterexamples to violated properties. We chose six existing tools for automatic testcase generation, namely aflfuzz, cpatiger, crestppc,fshell,klee,andprtest,andfourtoolsforsoftwaremodel. Abstract to detect a fault in software, a test case execution must be chosen so intermediate errors propagate to the output.

Citeseerx document details isaac councill, lee giles, pradeep teregowda. A set of atomic propositions is associated with each node. Issue in software testing with model checkers author. Modelbased testing is an application of modelbased design for designing and optionally also executing artifacts to perform software testing or system testing. Modelcheckers, however, were not originally intended for this task. We believe it is time for a careful comparative evaluation of automatic software test ing against automatic software model checking. Verification and test methods for access control policiesmodels. Models can be used to represent the desired behavior of a system under test sut, or to represent testing strategies and a test environment. This is typically associated with hardware or software systems, where the. Creating testcases incrementally with modelcheckers. Creating testcases incrementally with modelcheckers gordon fraser and franz wotawa. Existing stateless model checkers are limited to the veri.