Mutation testing for the agentic era

Summary: Trail of Bits announced MuTON and mewt, two open-source mutation testing tools built for agentic use, with MuTON supporting the TON blockchain languages FunC, Tolk, and Tact and mewt serving as a language-agnostic core that also covers Solidity, Rust, and Go. The tools use Tree-sitter as a parser and store mutants and test results in a SQLite database so campaigns can be paused and resumed, addressing limits of the regex-based universalmutator, which cannot mutate multi-line statements and lacks mutant prioritization.
Key Takeaway: The post cites a high-severity Arkis protocol vulnerability that mutation testing caught and coverage metrics missed, one that would have allowed attackers to drain funds - and it warns that an agent writing tests to catch mutants may encode a bug as expected behavior, corrupting the suite with false confidence.

Read the original at Trail of Bits Blog ↗