[[spring-mvc-test-vs-streaming-response]]
= Streaming Responses

The best way to test streaming responses such as Server-Sent Events is through the
<<WebTestClient>> which can be used as a test client to connect to a `MockMvc` instance
to perform tests on Spring MVC controllers without a running server. For example:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes",role="primary"]
----
	WebTestClient client = MockMvcWebTestClient.bindToController(new SseController()).build();

	FluxExchangeResult<Person> exchangeResult = client.get()
			.uri("/persons")
			.exchange()
			.expectStatus().isOk()
			.expectHeader().contentType("text/event-stream")
			.returnResult(Person.class);

	// Use StepVerifier from Project Reactor to test the streaming response

	StepVerifier.create(exchangeResult.getResponseBody())
			.expectNext(new Person("N0"), new Person("N1"), new Person("N2"))
			.expectNextCount(4)
			.consumeNextWith(person -> assertThat(person.getName()).endsWith("7"))
			.thenCancel()
			.verify();
----
======

`WebTestClient` can also connect to a live server and perform full end-to-end integration
tests. This is also supported in Spring Boot where you can
{docs-spring-boot}/html/spring-boot-features.html#boot-features-testing-spring-boot-applications-testing-with-running-server[test a running server].


