KtorEasy controller testing: controller's overview

RegistrationControllerImp.kt

class RegistrationControllerImp : BaseController(), RegistrationController, KoinComponent {

    private val userApi by inject<UserApi>()

    override suspend fun createUser(postUser: PostUserBody): ResponseUser {
        val user = dbQuery {
            userApi.getUserByUsername(postUser.username)?.let {
                throw InvalidUserException("User is already taken")
            }
            userApi.createUser(postUser) ?: throw UnknownError("Internal server error")
        }
        return user.toResponseUser()
    }
}