TestWithReactor.java

// Eventhough this Spring Bean is not referenced directly by the
// test, once you link it with the MockRestServerServer; all 
// calls made by it will be intercepted and checked.
@Autowired
private RestTemplate restTemplate;

@Autowired
private StockPublisher publisher;

@Test
public void testPublisher() throws IOException {
	
	String stock = "T";
	
	// Link the Rest Template bean with our MockRestServer
	MockRestServiceServer mockedServer = MockRestServiceServer.createServer(restTemplate);
	
	             // Define which request should we expect..
	mockedServer.expect(requestTo(String.format(YahooFeeder.YAHOO_URL,stock)))
	            // ... and the response that the Mock will provide (read from a text file)
		    .andRespond(withSuccess(Files.readAllBytes(sampleFilePath), MediaType.TEXT_HTML));

	// Get the target flux and create a logger flux from it
	Flux<StockQuotation> flux = publisher.getQuotes(Arrays.asList(stock)).log();
	
	// Reactor class that will help executing assertions over our tested flux
	TestSubscriber<StockQuotation> subscriber = new TestSubscriber<>();
	subscriber.bindTo(flux)
		  // Block until onComplete()
		  .await()
		   // Sample period contains 36 entries
		  .assertValueCount(36)
		  .assertComplete();
	
	// Verify that all the REST operations are performed according our specs
	mockedServer.verify();
}