Minor Description
When Hadoop tests are run, files and directories are created in /tmp .
Many (or all) of them are not cleaned when running "mvn clean".
This generates an issue when tests were previously run (by mistake) as root and then run again as a non-root user, since directories (like: .hdfs-nfs hadoop-root hsperfdata_root) cannot be written by second test run.
List of files/directories that seem to be created in /tmp when testing Hadoop:
Jetty* *test *deferred .hdfs-nfs hadoop-root hsperfdata_root
and that should be cleaned after tests.