@Test
	public void testStreamTap() {
		String data = UUID.randomUUID().toString();
		stream("dataSender",
				sources.http() + XD_DELIMITER
						+ sinks.log());
		stream(sources.tap("dataSender") + XD_TAP_DELIMITER
				+ sinks.file());

		sources.httpSource("dataSender").postData(data);
		assertValid(data, sinks.file());
	}
Evaluates whether the tap can retrieve data from a stream.
spring-xd-integration-test/src/test/java/org/springframework/xd/integration/test/TapTest.java