How do you ensure subclasses follow LSP?

Short answer: To ensure subclasses follow LSP: Subclasses should not override behavior in a way that breaks expected behavior.

Explain a bit more

Subclasses should preserve the invariants and preconditions/postconditions of the base class. Avoid overriding methods to throw exceptions for valid base class behavior. Use composition over inheritance if a subclass doesn’t strictly conform to the base class behavior. Write unit tests to verify that the subclass behaves identically to the base class in all valid scenarios. ✅ Ask yourself: Can this subclass be used anywhere the base class is used — without surprises?

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.