This is the jta/user-transaction module of the Java EE 7 Samples. The test checks that the UserTransaction object can be @Inject-ed via CDI and looked up from JNDI from java:comp/UserTransaction. Both tests pass on WildFly, but the JNDI one fails with Swarm.
I don't know where the problem is, but I doubt that Swarm would break JNDI in this way. I would suspect the Swarm Arquillian container, but that's probably just a red herring.
Steps to reproduce: