Software Testing Techniques Revisited for OWL Ontologies

Ontologies are an essential component of semantic knowledge bases and applications, and nowadays they are used in a plethora of domains. Despite the maturity of ontology languages, support tools and engineering techniques, the testing and validation of ontologies is a field which still lacks consolidated approaches and tools. This paper attempts at partly bridging that gap, taking a first step towards the extension of some traditional software testing techniques to ontologies expressed in a widely-used format. Mutation testing and coverage testing, revisited in the light of the peculiar features of the ontology language and structure, can can assist in designing better test suites to validate them, and overall help in the engineering and refinement of ontologies and software based on them

Impact of Test Suite Coverage on Overfitting in Genetic Improvement of Software

Genetic Improvement (GI) uses automated search to improve existing software. It can be used to improve runtime, energy consumption, fix bugs, and any other software property, provided that such property can be encoded into a fitness function. GI usually relies on testing to check whether the changes disrupt the intended functionality of the software, which makes test suites important artefacts for the overall success of GI. The objective of this work is to establish which characteristics of the test suites correlate with the effectiveness of GI. We hypothesise that different test suite properties may have different levels of correlation to the ratio between overfitting and non-overfitting patches generated by the GI algorithm. In order to test our hypothesis, we perform a set of experiments with automatically generated test suites using EvoSuite and 4 popular coverage criteria. We used these test suites as input to a GI process and collected the patches generated throughout such a process. We find that while test suite coverage has an impact on the ability of GI to produce correct patches, with branch coverage leading to least overfitting, the overfitting rate was still significant. We also compared automatically generated tests with manual, developer-written ones and found that while manual tests had lower coverage, the GI runs with manual tests led to less overfitting than in the case of automatically generated tests. Finally, we did not observe enough statistically significant correlations between the coverage metrics and overfitting ratios of patches, i.e., the coverage of test suites cannot be used as a linear predictor for the level of overfitting of the generated patches

Improvements in Coverability Analysis

In simulation-based verification users are faced with the challenge of maximizing test coverage while minimizing testing costs. Sophisticated techniques are used to generate clever test cases and to determine the quality attained by the tests. The latter activity, which is essential for locating areas of the design that need to have more tests, is called test coverage analysis

How to Overcome the Equivalent Mutant Problem and Achieve Tailored Selective Mutation Using Co-evolution

The use of Genetic Algorithms in evolution of mutants and test cases offers new possibilities in addressing some of the main problems of mutation testing. Most specifically the problem of equivalent mutant detection, and the problem of the large number of mutants produced. In this paper we describe the above problems in detail and introduce a new methodology based on co-evolutionary search techniques using Genetic Algorithms in order to address them effectively. Co-evolution allows the parallel evolution of mutants and test cases. We discuss the advantages of this approach over other existing mutation testing techniques, showing details of some initial experimental results carried out