Small example of how to create simple business tests with the help of Kotlin
The application is a part of the bigger, fake Veterinarian system. To simplify the project, all exceptions were packed to the one file, DTOs are as simple as possible and all repositories implementations are a simple Map in memory.
The main focus here are two classes - VeterinarianServiceTest with the "old style" tests and VeterinarianServiceBusinessTest which uses Kotlin features to create more readable tests.