@Test
	public void testFileSource() {
		String data = UUID.randomUUID().toString();
		String sourceDir = "/tmp/xd/" + UUID.randomUUID().toString();
		String fileName = UUID.randomUUID().toString() + ".out";
		stream(sources.file(sourceDir, fileName).label("filein") + XD_DELIMITER
				+ sinks.file().label("fileout"));
		setupSourceDataFiles(sourceDir, fileName, data);
		waitForXD();
		assertValid(data, sinks.file());
	}
Evaluates whether the file source (poller) will retrieve the specified file when it is added to the monitored
directory.
spring-xd-integration-test/src/test/java/org/springframework/xd/integration/test/FileSourceTest.java