How to merge jacoco coverage reports using 'merge goal' for multimodule project

[cbraj...@gmail.com]

Hi ,

I have a multimodule project. where i have configured jacoco for unit tests.

main
---module-a
---module-b

I have configured jacoco maven plugin in parent pom.xml

<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>${jacoco.version}</version>
<executions>
<execution>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
<execution>
<id>report</id>
<phase>prepare-package</phase>
<goals>
<goal>report</goal>

</goals>
</execution>
</executions>
</plugin>

when i run mvn clean install it runs unit tests and generates .exec in each of the module. But how do i get a merged/aggregated code coverage report of the 2 modules ?

where should configure the merge goal of jacoco , in the parent pom or individual POM ?
can some body tell me how to configure the jacoco for merged report?
what configurations to set and how to run it ?

Thanks!
Raj

[Marc Hoffmann]

Hi Raj,

as of now JaCoCo Maven goals do not support multi-module reports. We
hope to have a solution ready soon
(https://github.com/jacoco/jacoco/pull/388).

In the meantime a possible workaround is to embed an Ant script in your
Maven build which supports arbitrary input sources, see JaCoCo build for
an example:
https://github.com/jacoco/jacoco/blob/master/org.jacoco.doc/pom.xml#L90

Regards,
-marc

[cbraj...@gmail.com]

Thanks Marc for your reply !!

so if am not wrong the merge goal in Jacoco is useful to merge .exec files residing in same project/module and will not work with multi modules ?

when can we expect this feature to be in jacoco ?

Thanks!
Raj

[Marc R. Hoffmann]

Hi Raj,

even if this is not considered as a good practice you could probably
merge exec filed from multiple projects using relative paths.

The report-aggregate goal should be available with the next release in a
couple of weeks.

Regards,
-marc

[pille...@gmail.com]

I have a working but ugly solution. The trick here is to use the Maven undocumented parameter "${session.executionRootDirectory}" to set the jacoco destFile attribute. This works pretty well, and with it, I can have only one data file shared with every modules in a multi module project, no matter how much modules you have or how deep they are nested.

Additionnaly, that parameter is not recognized by sonar-maven-plugin, but I have another hack to make it works with Sonar too (ask me if you need it)