Unit Testing Java Applications using JUnit 5_468 x 60 copy.png

junit5.tar.gz

mvn clean test

Unit Testing is a basic and essential skill to learn for any developer. In this course, you will learn what unit tests are, why they are important, and how to test your Java applications using the JUnit 5 Framework —  the most popular unit testing framework in the market for Java developers.

You will start with the fundamentals of Unit Testing and JUnit 5 and then gradually you will dive deep into the core concepts like assertions, assumptions, different types of tests like nested tests, parameterized tests, repeated tests, and more.

You will also learn some advanced concepts of JUnit 5 like the JUnit 5 extension model, dependency injection, how to migrate existing unit tests from JUnit 4 to JUnit 5, and how to integrate your unit tests with Maven and Gradle.

Unit Testing Java Applications using JUnit 5



## AAA approach

AAA stands for **Approach-Act-Assert**.

- In the **Approach phase**, we initialize the piece of the unit we want to test.  This means we create the required objects and test data.

- In the **Act phase**, we execute the code to be verified. This is usually a method or a function.

- In the **Assert phase**, we verify whether the behavior of the method matches our expectations.

## Example

We’ll use the code below, the `Calculator.java` class,  to test and demonstrate the AAA approach.



# AAA approach

AAA stands for **Approach-Act-Assert**.

- In the **Approach phase**, we initialize the piece of the unit we want to test.  This means we create the required objects and test data.

- In the **Act phase**, we execute the code to be verified. This is usually a method or a function.

- In the **Assert phase**, we verify whether the behavior of the method matches our expectations.

# Example

We’ll use the code below, the `Calculator.java` class,  to test and demonstrate the AAA approach.

Learn to structure tests using the AAA approach.

Before We Begin

Introduction to JUnit 5

Junit 5 Core Concepts

Dynamic Tests

Dependency Injection in JUnit 5

JUnit 5 Extensions

Migrating from Junit 4 to Junit 5

Appendix

BONUS: Useful Assertion Libraries

Conclusion

Structuring Tests Using the AAA Approach

AAA approach

Example