What is Test Driven Development (TDD)?

Short answer: TDD is a software development approach where you write tests before writing the actual code. It follows a short, repetitive cycle of writing a failing test, implementing code to pass the test, and then refactoring.

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.