ReSuMo: a regression strategy and tool for mutation testing of solidity smart contracts

Mutation testing is a powerful test adequacy assessment technique that can guarantee the deployment of deeply scrutinized and more reliable Smart Contract code. However, regularly evaluating the test suite during the evolution of a project can be unfeasible due to the high costs of the assessment. This paper presents ReSuMo, the first regression mutation testing approach and tool for Solidity Smart Contracts. ReSuMo uses a static and file-level technique to select a subset of Smart Contracts to mutate, and a subset of test files to re-run during a regression mutation testing campaign. After each mutation testing run, ReSuMo incrementally updates the results using the test outcomes registered on the previous program revision. In this way, it can speed up the mutation testing process for evolving projects, while providing a comprehensive adequacy assessment of the whole test suite.