FYI, I am starting to write 2 new opinionated guides "Building Kotlin applications with Spring Boot and WebFlux" and "Building Kotlin applications with Spring Boot and Spring MVC" because there are too much possible variants and I feel you don't always find the information because it is splitted in too much distinct places (slides, Framework ref doc, Boot ref doc,
https://github.com/sdeleuze/ demo projects, Spring blogs, Kotlin Kdoc). There is a need for a pragmatic and canonical place where to find what look like such applications with all best practices. The WebFlux guide will use functional router DSL and handlers. Both will use Junit 5 +
@Autowired
injection and show how to do integrations tests and mocked tests.