Ai

There’s a class of bugs that took me a long time to recognize because they don’t look like bugs at all. Nothing crashes. Nothing fails tests. Nothing even looks wrong. And yet, a critical assumption about the system is no longer true. These are the bugs that happen when a guardrail is silently removed—intentionally or accidentally—and the system keeps working as if nothing changed. I’ve started thinking of these as “you don’t know what you don’t know” bugs. ...

“How do you approach testing?” I’ve been asked this in every interview I’ve had—and my answer tends to surprise people. Here’s my honest answer—and it’s shaped by years of shipping real products, not theory. I don’t believe in 100% test coverage as a universal rule. In theory, it’s a great goal. In practice, it can be difficult to manage without creating bad incentives. When teams mandate it, they often end up optimizing for passing tests, not useful tests. You get coverage numbers that look great, but tests that catch nothing and protect nothing. ...