JUnit Test with Maven in VSCode

Install VSCode

Setup here: https://code.visualstudio.com/docs/setup/setup-overview

Install and create a Maven project

Full Installation Guide here: https://maven.apache.org/guides/getting-started/maven-in-five-minutes.html

If you have Maven installed, follow these steps:

Generate the project

mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4 -DinteractiveMode=false

Change into project directory

cd my-app

Build the project

mvn package

Test and compile the project

java -cp target/my-app-1.0-SNAPSHOT.jar com.mycompany.app.App

You should get an output with:

Hello World!

Modify our project

Let’s start creating simple math functions

Search for App.java file and replace the contents with this code:

Search for AppTest.java and replace the contents with this code:

You can keep creating tests such as:

@Test    
public void multiply_FiftyTimesTwo_ReturnsOneHundred() 
{      
  // Arrange      
  final int expected = 100;        
  // Act      
  final int actual = App.multiply(50, 2);        
  // Assert      
  Assert.assertEquals(actual, expected);    
}

Build the project

mvn package

Output:

[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.mycompany.app.AppTest
[INFO] Tests run: 3, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.026 s - in com.mycompany.app.AppTest
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 3, Failures: 0, Errors: 0, Skipped: 0

Test and compile the project

java -cp target/my-app-1.0-SNAPSHOT.jar com.mycompany.app.App

Output:

6
Hello World!

An alternative way to run tests is by click Run Test inside AppTest.java

In the example below, Run Test is located just below code line 44.

View Tests and Test Report

Migrating JUnit 4 to JUnit 5

Change your pom.xml dependencies to:

Change your AppTest.java into:

Adding test coverage

Check the test coverage report

In the VSCode open the Extension MarketPlace and search Coverage Gutters

Click install button

Open the pom.xml file under your root folder and replace the content with http://bit.ly/2Df1Oj2 to add one plugin support.

Open the terminal in the VSCode and run

mvn install
mvn clean jacoco:prepare-agent install jacoco:report

Open your App.java file under main/java/com/mycompany/app folder and click the Watch button to check the report

Red bar: test code is not covered

Yellow bar: condition is not covered

Green bar: code is covered

Open the index.html file under your root folder/target/site/jacoco.

To open:

Then paste (Ctrl and V for Windows, Command and V for MacOS) the path in your browser.

You can see a very detailed test coverage report:

Thanks for reading! =)

Want to learn the different types of software testing? https://medium.com/@clarkjasonngo/easy-examples-for-black-white-and-gray-box-testings-fdceb2a8b664

Clark Jason Ngo - Graduate Teaching Assistant - Technology Institute - City University of Seattle |…

Test Coverage section contributor:

Kevin Wang - Full Stack Software Engineer - Resonance Path Institute | LinkedIn