JUnit is a popular testing framework for Java that allows developers to write and run repeatable tests for their code. It's the OG of unit testing frameworks, and if you're not using it, you're probably still stuck in the waterfall days.

How to use it in a sentence

• I was going to refactor that legacy code, but I couldn't because there were no JUnit tests and I didn't feel like spending my weekend writing them.

• Did you see the new JUnit 5 release? It's got some fancy new features, but I'm sure we'll still be stuck using JUnit 4 for the next decade because nobody wants to update the build pipeline.

If you actually want to learn more...

• Xunit - Martin Fowler gives a history lesson on the Xunit family of testing frameworks, including JUnit, and how they've influenced software development practices. Worth a read if you want to impress your coworkers with your knowledge of testing lore.

• The Practical Test Pyramid - This article dives into the different layers of the testing pyramid, including unit tests with JUnit, and provides examples using a Spring Boot app. Useful if you're trying to figure out how to structure your test suite.

• Unit Test - Fowler breaks down what exactly a "unit test" is and how the definition can vary depending on your programming paradigm. Good to know so you can settle those heated debates about whether your JUnit tests are really unit tests or not.

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