Support JaCoCo aggregated reports in test coverage visualization

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Proposal

Add support for JaCoCo aggregated reports in test coverage visualization.

Follows #227345 (closed) (and mentionned in #479804 (comment 2116912208)).

The current process works great in multi module projects if there are multiple JaCoCo reports, one in each module (see #227345 (comment 2059938471)).

  • module1
    • target/jacoco-report/jacoco.xml
  • module2
    • target/jacoco-report/jacoco.xml

For my projects, I have a different architecture. I have a report module that aggregate reports into a single one.

  • module1
  • module2
  • report (includes module1 and module2)
    • target/jacoco-report/jacoco.xml

The HTML report looks like this:

report

Reproducer

See project https://gitlab.com/jdussouillez/gitlab-jacoco-report-aggregate

  • PR #1: Test coverage visualization doesn't work because I use the aggregated report. code

PR1

  • PR #2: Test coverage visualization works because I use both module1 and module2 reports and not the one aggregated. code

PR2

Reports

Here the structure of a report for a single module:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE report PUBLIC "-//JACOCO//DTD Report 1.1//EN" "report.dtd">
<report name="myapp-module1">
    <package name="com/gitlab/jdussouillez/module1">
        <!-- [...] -->
    </package>
    <!-- [...] -->
</report>

And for an aggregate:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE report PUBLIC "-//JACOCO//DTD Report 1.1//EN" "report.dtd">
<report name="myapp">
    <group name="myapp-module1">
        <package name="com/gitlab/jdussouillez/module1">
            <!-- [...] -->
        </package>
        <!-- [...] -->
    </group>
    <group name="myapp-module2">
        <package name="com/gitlab/jdussouillez/module2">
            <!-- [...] -->
        </package>
        <!-- [...] -->
    </group>
    <!-- [...] -->
</report>

Implementation Guide

Cases to handle

  • If the <group> tag's name attr always contains the root dir's name, e.g. the directory names at the root of your project myapp-module1, myapp-module2,it allows us to infer the file in the edge case of having 2 files with identical paths, aside from their root dirs.

e.g. module-1/src/main/java/com/gitlab/jdussouillez/acme, my-app-module-2/src/main/java/com/gitlab/jdussouillez/acme

  • If the <group> tag's name attr doesn't contain the root dir's name, we can't support the above case and it will be a limitation to add to the docs.

We need to confirm with the JaCoCo maintainers if the group can be customized and if it is always populated when using the report-aggregate goal on the maven config.

Resources

Edited by 🤖 GitLab Bot 🤖