Test Case Generation Approach Research Articles

UML in action

This paper presents a novel model-based test case generation approach that automatically derives test cases from UML state machines. UML is given a two-layered formal semantics by (1) mapping UML class diagrams and state charts to Back's Action Systems, (2) by interpreting these action systems as labeled transition systems. The first semantics provides a formal framework to capture the object-oriented machinery: classes, objects, inheritance, transitions, time-outs, signals, nested and parallel regions. The second mapping represents the tester's view on the interface in terms of input and output actions. Tretman's input-output conformance relation (ioco) forms the basis of our fault models. Mutation analysis on the models is used to generate test cases. A car alarm system serves as a running example

Towards generation of efficient test cases from UML/OCL models for complex safety-critical systems

This paper describes a new approach for model-based test case generation (MBTCG) for large systems, which not only supports the expression of complex requirements (constraints) using OCL, but also lays ground for improving the efficiency (i.e. maximum coverage with minimal number of test cases) of the generated test case set. For that purpose, UML/OCL models are transformed to (object-oriented) action systems, where test cases are generated by means of mutation. The resulting "abstract" test cases represent input/output sequences with possible branches according to valid alternatives in system responses. They have finally to be transformed to "concrete" test cases which can be applied to the target application. The described work is part of the European project MOGENTES.

On the order of test goals in specification-based testing

Model-based testing techniques often select test cases according to test goals such as coverage criteria or mutation adequacy. Complex criteria and large models lead to large test suites, and a test case created for one coverage item usually covers several other items as well. This can be problematic if testing is expensive and resources are limited. Therefore, test case generation can be optimized in order to avoid unnecessary test cases and minimize the test generation and execution costs. Because of this optimization the order in which test goals are selected is expected to have an impact on both the performance of the test case generation and the size of resulting test suites, although finding the optimal order is not feasible in general. In this paper we report on experiments to determine the effects of the order in which test goals are selected on performance and the size of resulting test suites, and evaluate different heuristics to select test goals such that the time required to generate test suites as well as their size are minimized. The test case generation approach used for experimentation uses model checkers, and experimentation shows that good results can be achieved with any random ordering, but some improvement is still possible with simple heuristics.

When Model-based Testing Fails

Armando Haeberer made a substantial contribution in translating results from the philosophy of science to software testing. He showed that the limits of the standard methodology of confirming theories, where observations are derived from the theory and hypothesis, are also present in software testing. He criticized the classical test case generation approach from algebraic specifications, but also supplied an alternative based on Glymour's bootstrap approach. However, the debate that one would expect after his contribution never really happened. This is especially astonishing since most of the model-based testing approaches follow the method he criticized. This paper aims to open the debate by looking on his findings from a fresh point of view. We use the concept of refinement to clarify the fundamental issues involved in testing and discuss the practical consequences.

The role of modeling in the performance testing of e-commerce applications

An e-commerce scalability case study is presented in which both traditional performance testing and performance modeling were used to help tune the application for high performance. This involved the creation of a system simulation model as well as the development of an approach for test case generation and execution. We describe our experience using a simulation model to help diagnose production system problems, and discuss ways that the effectiveness of performance testing efforts was improved by its use.

A test case generation approach for conformance testing of SDL systems

This paper presents an approach for automatic executable test case and test sequence generation for a protocol modeled by an SDL system. Our methodology uses a unified method which tests an Extended Finite State Machine (EFSM) based system by using control and data flow techniques. To test an SDL system, it extracts an EFSM from each process then the system is tested by incrementally computing a partial product for each EFSM C, taking into account only transitions which influence (or are influenced by) C, and generating test cases for it. This process ends when the coverage achieved by the generated test cases is satisfactory or when the partial products for all EFSMs are tested. Experimental results show that this method can be applied to systems of practical size.