Maven2 Multiproject Cobertura Reporting Problems During mvn site Build

Question

We've got a multiproject we're trying to run Cobertura test coverage reports on as part of our mvn site build. I can get Cobertura to run on the child projects, but it erroneously reports 0% coverage, even though the reports still highlight the lines of code that were hit by the unit tests.

We are using mvn 2.0.8. I have tried running mvn clean site, mvn clean site:stage and mvn clean package site. I know the tests are running, they show up in the surefire reports (both the txt/xml and site reports). Am I missing something in the configuration? Does Cobertura not work right with multiprojects?

This is in the parent .pom:

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>cobertura-maven-plugin</artifactId>
                <inherited>true</inherited>
                <executions>
                    <execution>
                        <id>clean</id>
                        <goals>
                            <goal>clean</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </pluginManagement>
</build>
<reporting>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>cobertura-maven-plugin</artifactId>
            <inherited>true</inherited>
        </plugin>
    </plugins>
</reporting>

I've tried running it with and without the following in the child .poms:

    <reporting>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>cobertura-maven-plugin</artifactId>
        </plugin>
    </plugins>
</reporting>

I get this in the output of the build:

...
[INFO] [cobertura:instrument]
[INFO] Cobertura 1.9 - GNU GPL License (NO WARRANTY) - See COPYRIGHT file
Instrumenting 3 files to C:\workspaces\sandbox\CommonJsf\target\generated-classes\cobertura
Cobertura: Saved information on 3 classes.
Instrument time: 186ms

[INFO] Instrumentation was successful.
...
[INFO] Generating "Cobertura Test Coverage" report.
[INFO] Cobertura 1.9 - GNU GPL License (NO WARRANTY) - See COPYRIGHT file
Cobertura: Loaded information on 3 classes.
Report time: 481ms

[INFO] Cobertura Report generation was successful.

And the report looks like this:

Answer 1

I suspect that you're missing an execution of cobertura plugin during the compile phase so that the code only gets instrumented by the reporting plugins, in the site lifecycle, after the tests were run. So the test runs aren't picked up because they run on non-instrumented code. Analyze your build logs more carefully - if I'm right, you'll notice that surefire tests are executed before cobertura:instrument.

My configuration is similar to yours, but in addition to specifying the clean exectution in pluginManagement (like you), I specify the cobertura plugin explicitly in build plugins section:

  <build>
  ...
    <plugins>
    ...
      <plugin>
        <inherited>true</inherited>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>cobertura-maven-plugin</artifactId>
        <version>${cobertura.plugin.version}</version>
      </plugin>
    </plugins>
  </build>

My configuration sorta works, and all Cobertura stuff is in the global organization-wide pom, which all projects use as a parent.

This way projects don't specify anything Cobertura-related in their pom.xml's, but they still generate coverage reports.