Pragmatic Unit Testing in Java with JUnit, 3rd Edition

Learning JUnit Basics: Your First Testing Challenge

For your first example, you’ll work with a small class named CreditHistory. Its goal is to return the mean (average) for a number of credit rating objects.

In this book, you’ll probe the many reasons for choosing to write unit tests. For now, you’ll start with a simple but critical reason: you want to continue adding behaviors to CreditHistory and want to know the moment you break any previously coded behaviors.

Initially, you will see screenshots to help guide you through getting started with JUnit. After this chapter, you will see very few screenshots, and you won’t need them.

The screenshots demonstrate using JUnit in IntelliJ IDEA. If you’re using another integrated development environment ...