As a summary, these are the key takeaways of this guide:

The Spring Boot Starter Test adds a solid testing foundation to each Spring Boot project.

Test dependency versions are managed by Spring Boot but can be overridden.

JUnit is the testing framework to launch tests on the JVM.

Mockito is the de-facto standard mocking framework for Java projects.

Pick one assertion library for writing tests: JUnit's built-in assertions, Hamcrest or AssertJ.

Both JSONassert and JsonPath help writing tests for JSON data structures.