Could you write up a little story to explain the sample in this test case?

Why it's here, what it shows, how it's invoked, use cases etc. :)

See https://github.com/javaee-samples/javaee7-samples/blob/master/jaxrs/async-client/src/test/java/org/javaee7/jaxrs/asyncclient/MyResourceTest.java as a example for how it works. This currently renders as http://javaee-samples.github.io/sample/jaxrs-async-client/index.html