In computer science, test coverage is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs. A program with high test coverage, measured as a percentage, has had more of its source code executed during testing, which suggests it has a lower chance of containing undetected software bugs compared to a program with low test coverage. (Wikipedia)
For pull requests and main pushes we generate code coverage reports on taskcluster and they can be accessed via the GitHub checks.
Generating reports locally
Locally you can generate a coverage report for a module with the following command:
./gradlew -Pcoverage <module>:build
After that you’ll find an HTML report at the following location:
components/<path to module>/build/reports/jacoco/jacocoTestReport/html/index.html