What are the differences between MSTest and other frameworks like NUnit and xUnit?

Short answer: MSTest is Microsoft's official framework; NUnit and xUnit are community-driven. MSTest uses [TestClass] and [TestMethod] attributes; xUnit uses [Fact], NUnit uses [Test]. MSTest has less flexibility in data-driven tests compared to NUnit’s [TestCase] and xUnit’s [Theory]. xUnit promotes constructor-based setup, MSTest uses [TestInitialize].

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.