Testing value objects

How to test things like immutability

Transcript

1. TDD 101 2. TDDing Value Objects
2. TDDing Value Objects
3. Value Object (DDD) Small object Represents a concept Equality based on value Immutable: • Should be created consistent • Mutators should return new instances
4. So… How do you TDD a VO?
5. TDD VO Think of an invalid example Write a test that fails expecting exception Make the test pass Repeat as needed to test invalid cases
6. TDD VO Think of a valid example Write a test that fails asserting value Make the test pass
7. TDD VO Equality Write a test that fails expecting inequality Make the test pass Then write a test that fails expecting equality Make the test pass
8. TDD VO Immutability Think of a valid example of a mutator Write a test that fails expecting a different instance Make the test pass