impl-base POM has:

<build>
 <plugins>
 <plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-jar-plugin</artifactId>
 <executions>
 <execution>
 <goals>
 <goal>test-jar</goal>
 </goals>
 </execution>
 </executions>
 </plugin>
 </plugins>
 </build>

I remember talking with Aslak about this because we wanted to promote test class reuse as detailed:

http://maven.apache.org/guides/mini/guide-attached-tests.html

1) I thought he'd mentioned that in newer versions of Maven this explicit config was not required. True?
2) If still needed, we can/should centralize this in the "build" project

S,
ALR