Summary
This episode introduces mutation testing with the Mull tool, which helps evaluate test suite quality by modifying source code to create 'mutants' and checking if tests detect these changes. Jason demonstrates how Mull operates as a Clang/LLVM plugin that modifies code at the intermediate representation level, showing how it can identify gaps in test coverage by changing conditional operators. Through examples, he illustrates how mutation testing can guide developers to create more robust test cases by revealing which code modifications are undetected by existing tests.