http://maven.apache.org/core-its/
If you want to run the integration tests against a custom build of Maven use the following command:
mvn clean install -Prun-its -Dmaven.repo.local=`pwd`/repo -DmavenDistro=/path/to/apache-maven-dist.zip
or if behind a proxy
mvn clean install -Prun-its -Dmaven.repo.local=`pwd`/repo -DmavenDistro=/path/to/apache-maven-dist.zip -Dproxy.active=true -Dproxy.type=http -Dproxy.host=... -Dproxy.port=... -Dproxy.user=... -Dproxy.pass=...
Maven Developers List: dev@maven.apache.org