Some of the XTS unit test EARs contain no longer supported namespace in META-INF/jboss-beans.xml and so they cannot be deployed to AS7. See  for the current namespace used in XTS unit test EARs and  for the valid namespace that should be used in AS7. A bit weird is that those EARs can be successfully deployed by command line copy and by web admin console, but only deploying by Arquillian uncovered the issue. I've already filed a jira for that -
Please could you take a look at that and fix the namespace?
Here is a list of the affected EARs: