A comprehensive guide to testing Spring Boot applications covering three layers: unit testing services and controllers with JUnit 5 and Mockito, integration testing with TestContainers spinning up a real PostgreSQL Docker container, and microservice integration testing using MockServer via TestContainers. Includes full code examples for UserService, UserController, and UserRepository tests, plus Hystrix circuit breaker timeout and failure scenario testing with MockServer.
Table of contents
Create SpringBoot ApplicationUnit Testing using JUnit 5 and MockitoIntegration Testing using TestContainersTesting MicroService Integrations using MockServerSort: