### Question:
OutboundQueueEntry { OfHeader takeMessage() { final OfHeader ret = message; if (!barrier) { checkCompletionNeed(); } message = null; return ret; }   static final Function<OfHeader, Boolean> DEFAULT_IS_COMPLETE; }### Answer:
@Test public void takeMessage() throws Exception { outboundQueueEntry.commit(packetOutInput, futureCallback); outboundQueueEntry.takeMessage(); Mockito.verify(futureCallback).onSuccess(Mockito.<OfHeader>any()); }