Improve async test by removing sleep in DefaultAsyncServerResponseTests

Signed-off-by: suhwa Park <suhwaparkk1031@gmail.com>
Signed-off-by: hydrationn <suhwaparkk1031@gmail.com>

spring-webmvc/src/test/java/org/springframework/web/servlet/function/DefaultAsyncServerResponseTests.java

@@ -39,17 +39,11 @@ class DefaultAsyncServerResponseTests {
 	@Test
 	void blockNotCompleted() {
 		ServerResponse wrappee = ServerResponse.ok().build();
-		CompletableFuture<ServerResponse> future = CompletableFuture.supplyAsync(() -> {
-			try {
-				Thread.sleep(500);
-				return wrappee;
-			}
-			catch (InterruptedException ex) {
-				throw new RuntimeException(ex);
-			}
-		});
+		CompletableFuture<ServerResponse> future = new CompletableFuture<>();
 		AsyncServerResponse response = AsyncServerResponse.create(future);
 
+		new Thread(() -> future.complete(wrappee)).start();
+
 		assertThat(response.block()).isSameAs(wrappee);
 	}