Why Your Test Suite Needs Mutation Testing

In episode 16 of Software Testing with Fexingo, Lucas and Luna explore mutation testing—a technique that injects small faults into your code to see if your tests catch them. They break down how it works using a real-world example: a payment processing function that passes all unit tests but silently rounds pennies incorrectly. Lucas explains why traditional code coverage tells you what code ran, not whether it was checked properly, and how mutation testing exposes weak assertions and untested edge cases. They discuss practical adoption: starting small with a single module, handling the surge of false positives with partial mutations, and integrating it into CI pipelines without killing your build time. Luna shares how her team at a fintech startup used mutation testing to catch a subtle rounding bug that would have cost thousands in fees. They also touch on the cultural shift required—teams need to embrace breaking code deliberately. A concrete episode for QA engineers and developers who want their test suites to actually prove correctness, not just check a coverage box. #MutationTesting #SoftwareTesting #QA #Automation #TestCoverage #CodeQuality #TestDesign #CI #DevOps #Fintech #PaymentProcessing #EdgeCases #FalsePositives #TestReliability #EngineeringCulture #Technology #FexingoBusiness #BusinessPodcast Keep every episode free: buymeacoffee.com/fexingo