JaCoCo setup and configuration in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is JaCoCo used for in software testing?

JaCoCo is a tool that measures how much of your code is tested by your unit tests. It helps you see which parts of your code are covered and which are not.

beginner

How do you add JaCoCo to a Maven project?

You add the JaCoCo plugin in your pom.xml under build > plugins. This plugin runs during the test phase and generates coverage reports.

intermediate

What is the purpose of the jacoco-maven-plugin in the build process?

The jacoco-maven-plugin instruments the code during tests to collect coverage data and then generates reports showing which code was executed.

beginner

Which JaCoCo report formats are commonly used?

JaCoCo can generate reports in HTML (for easy viewing in browsers), XML (for integration with other tools), and CSV formats.

intermediate

How can you configure JaCoCo to fail the build if coverage is below a threshold?

In the JaCoCo plugin configuration, you can set rules with check goals specifying minimum coverage percentages. If coverage is below these, the build fails.

What phase of the Maven build lifecycle does JaCoCo typically run in?

A compile

B package

C test

D install

JaCoCo runs during the test phase to collect coverage data while tests are executed.

Which of these is NOT a report format generated by JaCoCo?

A HTML

B XML

C CSV

D PDF

JaCoCo does not generate PDF reports by default; it supports HTML, XML, and CSV.

How do you add JaCoCo to a Gradle project?

A Apply the 'jacoco' plugin in build.gradle

B Add JaCoCo dependency in dependencies block

C Include JaCoCo jar in src folder

D Run JaCoCo as a separate command line tool

In Gradle, you apply the 'jacoco' plugin in your build.gradle file to enable coverage.

What does JaCoCo instrument in your project?

A Test classes only

B Source code classes

C Build scripts

D Documentation files

JaCoCo instruments the source code classes to track which parts are executed during tests.

Which Maven plugin goal generates the JaCoCo coverage report?

A jacoco:report

B jacoco:clean

C jacoco:check

D jacoco:prepare-agent

The 'jacoco:report' goal generates the coverage report after tests run.

Explain how to set up JaCoCo in a Maven project to generate coverage reports.

Think about where in the build file and lifecycle JaCoCo fits.

Describe how JaCoCo helps improve code quality in testing.

Consider how coverage data influences testing decisions.