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Gradle: Test test

Testing Testing Testing...

A few weeks ago we focused on JUnit testing using Gradle. I thought I would share a few things I learned along the way getting my projects setup for JUnit testing with Gradle. Since our testing is centered around Jupiter (JUnit5) there are a few unique things you need to do to get Gradle to behave as expected.

If you are using Jupiter for your JUnit testing you need to have Gradle version 4.6 or later installed. So let's start there.

Verify the version of Gradle you have installed:

Open a bash shell in your projects root directory and run:

./gradlew --version

If you are not running a version greater than 4.6 update to the latest version before proceeding.

Let's setup our project to use Gradle. Open a bash shell in your projects root folder and run this:

gradle init --type java-library --dsl groovy --test-framework junit

This tells Gradle that we are creating a new JAVA project and that we will be testing with JUnit.

It will take a few seconds to run and once complete you should see a message that says:


2 actionable tasks: 2 executed

Now check out your project folder. You will now see 3 new folders:




and the following new files:






We are going to start off making changes to the build.gradle file. Using your favorite editor (I prefer Notepad++)open build.gradle and verify that the following is your frist entry following the commented docs:

1 plugins {

2 // Apply the java-library plugin to add support for Java Library

3 id 'java-library'

4 }

This tells Gradle that it is going to be building a JAVA program. Now we need to make sure that Gradle gets the required and dependencies so add the following to build.gradle:

20 dependencies {

21 // This dependency is exported to consumers, that is to say found on their compile classpath.

22 api 'org.apache.commons:commons-math3:3.6.1'

24 // This dependency is used internally, and not exposed to consumers on their own compile classpath.

25 implementation ''

26 // Use JUnit test framework

27 testImplementation 'junit:junit:4.12'

28 testImplementation 'org.junit.jupiter:junit-jupiter-api:5.5.0-M1'

29 testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.5.0-M1'

30 }

We tell build.gradle which frameworks to include for the JUnit testing. Jupiter is backwards compatible but if we want to run any JUnit 4 test we include that junit:4.12 dependency. This just ensure the correct flavor of JUnit is used for the testing. Now we'll add one more line to our build.gradle to make sure we enable Gradle's native JUnit 5 support. Add the following lines after the dependencies:

33 test {

34 useJUnitPlatform()

35 }

Now hop back into your IDE and work on your project. Save all of your changes and navigate back to your project folder. Open up the src folder. You will see the following sub-folders:



Both of these contain a folder called java. You will move your JAVA files into the java folders in the main and test subfolders.


Let's say I am working a project that has , , and Both and should be moved to ../src/main/java and would be moved to ../src/test/java

Once you've moved your files into the correct location run this in your bash shell:

gradle build

Once this succeeds run this in your bash shell:

gradle test

Once this finishes and you get a success message navigate to your project folder and go to /build/reports/tests/test/ and open up the index.html. This will give you a breakdown of how your gradle test went.

Now that you've sucessfully setup Gradle you need to go back into your IDE and clean up your projects paths so that you are working in the src/main/java folder and the src/test/java folder.

See easey peasey lemon squeezy! Next week we'll go over how to intigrate our projects with GitLab so that GitLab does the testing for us. In the meantime checkout the docs up on related to testing with JAVA & JVM:

#CS@Worcester #CS443

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