Basic integration test for REST api module generated with atlas-generate-jira-module fails

If I generate an new jira plugin and additionally a basic rest api module (with atlas-generate-jira-module) the generated integration test fails (started from the testing console in Jira 7.13 Server). The error message is “java.lang.RuntimeException: A implementation was not found for class …”. What do I have to add to make the automatically generated code working?

This line causes the problem: client.resource(resourceUrl).get(MessageResource.class).