Unit tests are crucial for any serious software application, and while most developers agree, it's often their least favorite task.

In the Java ecosystem, JUnit is the go-to testing framework, and writing tests may seem straightforward at first glance. However, developers often face common concerns and misconceptions, such as: Mock or Spy? @Mock or @MockBean? Should the test be @Transactional? When to use Parameterized tests? At this stage, understanding JUnit's lifecycle, mocking extensions, and database integrations becomes vital.

In this session, I’ll explore a series of puzzlers that guide you through the journey from plain JUnit tests to Mockito integration and Spring Boot tests. By the end, you'll walk away with new insights and a deeper understanding of JUnit, Mockito, and Spring Boot testing, and hopefully, a newfound appreciation for Java testing.