How Mutation Testing Exposes the Truth (PHP 2026 Edition)

You've got 85% code coverage. Your CI pipeline is green. You ship to production — and things break in ways your tests never caught. Sound familiar? I've been there. And for a long time, I thought the answer was more tests. What I actually needed was better tests. That's exactly what mutation testing taught me, and after using Infection PHP in production projects through 2025 and into 2026, I can confidently say it changed how I think about test quality entirely. Previous article in this catego...