Test Edge Cases: Ensure that the microservice under test can handle all scenarios,?

Short answer: including success, failure, and unexpected behavior from dependencies. Tools: Mockito (Java) WireMock (for mocking HTTP services) unittest.mock (Python) Nock (for mocking HTTP requests in Node.js)

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

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.