What is code coverage and how useful is it?

Short answer: Code coverage measures the percentage of code executed by tests. It helps identify untested parts but doesn’t guarantee test quality. High coverage with meaningful tests improves confidence in code correctness. xUnit Framework

Real-world example (ShopNest)

ShopNest unit tests cover pricing and discount rules so a bad coupon change fails in CI before customers see it.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.