Is there a way to get unit coverage percentage (eg from jacoco) on only new code?

Question

My hypothethical scenario is this:

• I have run my junit tests and generated a jacoco file
• my git diff shows I have changed 10 lines of code

Now the intersection of my git diff and the jacoco information is that 7 of the 10 lines of code changed are covered. ie - I have 70% coverage on new code.

But I had to work that out manually.

I'd like an automated way to work out the percentage how many new lines of code are covered.

My question is: Is there a way to get unit coverage percentage (eg from jacoco) on only new code?

(Note I know sonarqube can do this if you run the scanner with analysis.mode=publish and get interrogate the task result with the JSON API - I'm looking for something lightweight that a developer can run locally.)

Answer 1

There are two plugins:

• Gradle: diff coverage gradle plugin
• Maven: diff coverage maven plugin

Both are built on top of JaCoCo and able to generate JaCoCo like reports.

Also, they able to fail the build if your coverage ratio is less than expected(the ratio colud be configured by the plugins)

Answer 2

Jacoco + diff-cover

It is work for me. CI Shell script:

export PATH="${jobPath}"/buildbox/Python-3.8.2/bin:$PATH
python --version
python -m pip install -i http://xx.xx.xx.com/artifactory/api/pypi/xx-pypi-public/simple/ --trusted-host xx.xx.xx.com diff_cover==4.0.1

mvn clean test -Dmaven.test.failure.ignore=true

diff-cover "${WORKSPACE}"/xxx-test/target/site/jacoco/jacoco.xml --compare-branch origin/"${target_branch}" --src-roots $(find . -name java -type d | grep 'src/main/java$' | egrep -v "target|test|testkit") --html-report ${WORKSPACE}/xxx-test/target/site/jacoco/index.html