Unit Testing with JUnit & Mockito

In this lesson, you'll learn to write effective unit tests for your Spring Boot applications, specifically focusing on the service layer.

Unit tests are crucial for ensuring your code works as expected and catching bugs early in development. We'll use JUnit 5 and Mockito.

Unit testing means testing the smallest possible piece of code, called a 'unit', in isolation. For Java, a unit is typically a single method or class.

• Isolation: Tests run independently, without external dependencies.
• Speed: They execute very quickly, allowing frequent runs.
• Early Detection: Catch bugs before they grow into bigger problems.