Describe a time when you had to refactor code to make it testable.

Short answer: I once refactored a tightly coupled class by introducing interfaces and dependency injection, enabling mock dependencies and isolated unit testing, which improved code quality and test coverage.

Real-world example (ShopNest)

Arrange a cart with 2 items → Act Checkout() → Assert total and that payment was called once.

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.