Spring Boot Pre-Interview Guide Part 2: Database & Testing — Spring Boot 4 · Kotlin Environment Separation, Test Pyramid, Testcontainers
On a Spring Boot 4 + Kotlin stack — picking the right DB per environment, the ddl-auto policy, gotchas when implementing a Memory Repository, choosing annotations along the Test Pyramid, when to reach for Dummy/Stub/Spy/Mock/Fake, and using Testcontainers to surface the bugs H2's dialect differences hide. Written with data classes and val/var instead of Lombok. Series Part 2.
