Remove STOMP relay integration test

The test was verifying that when a DISCONNECT frame is sent to the
broker, there will be no further messages on the clientOutboundChannel.

This is generally true, however in some cases when the broker receives
a DISCONNECT it may close its connection fast enough (before we do) in
which case we send an ERROR message downstream to ensure the WebSocket
side is cleaned up. Either way the downstream should be idempotent
with regards to cleaning up sessions.

spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandlerIntegrationTests.java

@@ -33,7 +33,6 @@
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TestName;
-
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.messaging.Message;
@@ -49,7 +48,9 @@
 import org.springframework.util.Assert;
 import org.springframework.util.SocketUtils;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
 
 /**
  * Integration tests for {@link StompBrokerRelayMessageHandler} running against ActiveMQ.
@@ -229,25 +230,6 @@ public void relayReconnectsIfBrokerComesBackUp() throws Exception {
 		this.eventPublisher.expectBrokerAvailabilityEvent(true);
 	}
 
-	@Test
-	public void disconnectClosesRelaySessionCleanly() throws Exception {
-
-		logger.debug("Starting test disconnectClosesRelaySessionCleanly()");
-
-		MessageExchange connect = MessageExchangeBuilder.connect("sess1").build();
-		this.relay.handleMessage(connect.message);
-		this.responseHandler.expectMessages(connect);
-
-		StompHeaderAccessor headers = StompHeaderAccessor.create(StompCommand.DISCONNECT);
-		headers.setSessionId("sess1");
-		this.relay.handleMessage(MessageBuilder.createMessage(new byte[0], headers.getMessageHeaders()));
-
-		Thread.sleep(2000);
-
-		// Check that we have not received an ERROR as a result of the connection closing
-		assertTrue("Unexpected messages: " + this.responseHandler.queue, this.responseHandler.queue.isEmpty());
-	}
-
 	@Test
 	public void disconnectWithReceipt() throws Exception {