Gain insights into JUnit 5, explore its advantages over JUnit 4, and delve into its features like assertions, parameterized tests, dependency injection, and test execution order. Discover hands-on projects to cement your skills.

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JUnit 5 is a standard framework for unit testing in Java. Released in 2017, JUnit 5 is a major improvement over JUnit 4 and supports a lot of new methods. Many projects have migrated from JUnit 4 to JUnit 5. JUnit 5 is also the default test framework for new projects. JUnit 5 is composed of three sub-projects: JUnit Platform, JUnit Jupiter, and JUnit Vintage. Details of these sub-projects are discussed in the course.

This course first discusses the advantages of JUnit 5 over the previous versions and then jumps directly into tests. The course includes discussion on assertions, assumptions, tagging and filtering, nested tests, dependency injection, repeated tests, parameterized tests, dynamic tests, test instance lifecycle, extension model, JUnit 4 migration, JUnit platform, and test execution order. 

By the end of this course, you’ll be deeply familiar with unit testing in JUnit 5. There’s also a little project for you at the end to put your newly acquired skills to the test.

All About JUnit5

# Simple display names 
In JUnit 5, we can use `@RepeatedTest` to make a test run multiple times. However, all these repetitions are identical. The `@RepeatedTest` simply runs the same test over and over. To run a test multiple times differently, we can use the parameterized tests.

Just as with `@RepeatedTest`, the `org.junit.jupiter.params.ParameterizedTest` annotation can be used to replace `@Test`. The test method should have at least one parameter. We also need to provide at least one source to provide the actual arguments for each invocation. In the code below, the test method `simpleValue` has an int parameter, `num`, and we assert that `num` should be greater than zero. The `org.junit.jupiter.params.provider.ValueSource` annotation provides static values for arguments. We provide three integers here.
In the code below, in the `simpleValue()` function, `assertTrue()` checks the condition. If it’s `num%2 == 0`, the condition passes. Otherwise, it fails.

Understand how to use parameterized tests with a simple and custom display name.

Getting Started

Writing Basic Tests

Annotations, Tagging, and Filtering

Nested tests in JUnit 5

Dependency Injections

Parameterized and Dynamic Tests

Test Instance Lifecycle in JUnit 5

Extension Model

JUnit Platform

Test Execution Order

Conclusion

Library Management System

Simple Parameterized Test

Simple display names