MMT: Mutation Testing of Java Bytecode with Model Transformation -- An Illustrative Demonstration

TL;DR

This paper introduces MMT, a model-driven mutation testing tool for Java bytecode that supports complex, domain-specific mutations, enhancing the robustness evaluation of test suites.

Contribution

It presents a novel model transformation approach for defining mutations in Java bytecode, enabling flexible and advanced mutation operators.

Findings

Supports complex object-oriented mutations

Extends mutation operators to Java-specific features

First tool to support such mutations in Java bytecode

Abstract

Mutation testing is an approach to check the robustness of test suites. The program code is slightly changed by mutations to inject errors. A test suite is robust enough if it finds such errors. Tools for mutation testing usually integrate sets of mutation operators such as, for example, swapping arithmetic operators; modern tools typically work with compiled code such as Java bytecode. In this case, the mutations must be defined in such a way that the mutated program still can be loaded and executed. The results of mutation tests depend directly on the possible mutations. More advanced mutations and even domain-specific mutations can pose another challenge to the test suite. Since extending the classical approaches to more complex mutations is not well supported and is difficult, we propose a model-driven approach where mutations of Java bytecode can be flexibly defined by model transformation. The corresponding tool called MMT has been extended with advanced mutation operators for modifying object-oriented structures, Java-specific properties and method calls of APIs, making it the only mutation testing tool for Java bytecode that supports such mutations.