Type Testing with expectTypeOf and tsd
Assert type correctness alongside runtime behavior.
Welcome
Testing types themselves — not just runtime behavior — ensures your TypeScript utilities and generic types work correctly.
Why Test Types
Generic utilities and conditional types can have bugs that only affect certain type arguments. Type tests catch these.
All lessons in this course
- Jest Setup for TypeScript with ts-jest
- Writing Type-Safe Unit Tests
- Mocking Modules and Functions in TypeScript
- Type Testing with expectTypeOf and tsd