### Question:
SourceApp { @PostMapping public void handle(@RequestParam final String name) { final Person person = new Person(name); final Message<?> message = MessageBuilder.withPayload(person).build(); source.output().send(message); } SourceApp(final Source source); static void main(final String[] args); @PostMapping void handle(@RequestParam final String name);  }### Answer:
@Test public void testHandle() throws Exception { final MultiValueMap<String, String> request = new LinkedMultiValueMap<>(); request.add("name", "hoge"); testRestTemplate.postForEntity("/", request, Void.TYPE); final BlockingQueue<Message<?>> queue = messageCollector.forChannel(source.output()); assertEquals(1, queue.size()); final Message<?> message = queue.remove(); assertEquals("{\"name\":\"hoge\"}", message.getPayload()); }