A Study on the Number of Composite Layers and Effectiveness of Metamorphic Relation

Metamorphic Testing is one of the main methods to alleviate the test Oracle problem, centered on metamorphic relation. Currently, the construction of the metamorphic relation mainly relies on manual analysis. Therefore, the systematic generation method has been the research concern. One of the construction methods is the composition of existing metamorphic relations. Research shows that the composited metamorphic relations have better fault detection capability than component ones. However, the more composite layers there are, the more time-consuming the computation becomes; even a combination explosion will be triggered. So, studying the mechanism of the number of composite layers on cost-effectiveness is very important. Firstly, combined operation is defined for the numerical expression type metamorphic relation. Then, experiments carry out the trend of the number of composite layers and cost-effectiveness and conclude that three is the most cost-effective, which is good guidance for the systematic generation of metamorphic relations.