As discussed on mailing list:
http://lists.jboss.org/pipermail/hibernate-dev/2013-June/010001.html

We would need to verify it is not mocking MongoDB.

Today if you don't have environment variables defined which specify the MongoDB hostname and port, the MongoDB build is skipped.

We should instead use this embedded mode to automatically install and run it; however this should not happen if the environment variables are specified, so that we can use a different external server in case of need.