Testing: Jacoco via Maven

Setting up Jacoco test coverage, using Maven

First: read about using Maven at these pages:

• Maven intro: https://ucsb-cs56-pconrad.github.io/topics/maven/
• Apache 5 minute guide to Maven: https://maven.apache.org/guides/getting-started/maven-in-five-minutes.html
• Converting an Ant Project to Maven: https://ucsb-cs56-pconrad.github.io/topics/maven_convert_ant_to_maven/

Then, here’s what you need to do to get Jacoco Test Coverage working for your project.

You need to have your Maven Project set up for JUnit

As a reminder, in a Maven project:

• Regular application code goes under /src/main/java
• JUnit test code goes under /src/test/java

To use JUnit in a Maven project, you need the JUnit dependency in your pom.xml file:

<project>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

Next, add in a plug-in for Jacoco:

There are many examples online of various ways to get Jacoco support in your pom.xml.

Here are a few:

• https://www.petrikainulainen.net/programming/maven/creating-code-coverage-reports-for-unit-and-integration-tests-with-the-jacoco-maven-plugin/

• https://www.javaworld.com/article/2074515/core-java/unit-test-code-coverage-with-maven-and-jacoco.html

Troubleshooting Jacoco

1. Make sure you have the latest version of the jacoco
2. Make sure you do mvn test then mvn jacoco:report then mvn site:deploy
3. Make sure that you git add docs, commit and push so that the latest version is online.
4. If you reset <argLine>, make sure that you add ${argLine} inside your new setting.
   • WRONG: <argLine>-Xmx1024M </argLine> (If it were Java, this would be: argLine="-Xmx1024M" )
   • CORRECT: <argLine>-Xmx1024M ${argLine}</argLine> (In Java, this would be: argLine = "-Xmx1024M " + argLine)