@Test
	public void testTuplePropertyAccessor() throws Exception {
		logger.info("Creating stream with temp File 'tupletest' as sink");
		FileSink sink = newFileSink().binary(true);
		HttpSource source = newHttpSource();

		stream().create(
				generateStreamName(),
				"%s | json-to-tuple | transform --expression=payload.foo | %s",
				source, sink);

		source.ensureReady().postData("{\"foo\":\"bar\"}");

		assertThat(sink, eventually(hasContentsThat(equalTo("bar"))));
	}
This test focuses on tuple access. Note that it explicitly creates a tuple out of Json, which is no longer
required for end-user usecases (see {@link #testJsonPropertyAccessor()}).
spring-xd-shell/src/test/java/org/springframework/xd/shell/command/AbstractSpelPropertyAccessorIntegrationTests.java