Append suffx to user dest in SimpMessagingTemplate

Isssue: SPR-11868

spring-messaging/src/test/java/org/springframework/messaging/simp/SimpMessagingTemplateTests.java

@@ -118,6 +118,25 @@ public class SimpMessagingTemplateTests {
 		assertNull(headerAccessor.getNativeHeader("key"));
 	}
 
+	// SPR-11868
+
+	@Test
+	public void convertAndSendWithCustomDestinationPrefix() {
+		this.messagingTemplate.setUserDestinationPrefix("/prefix");
+		this.messagingTemplate.convertAndSendToUser("joe", "/queue/foo", "data");
+		List<Message<byte[]>> messages = this.messageChannel.getMessages();
+
+		assertEquals(1, messages.size());
+
+		Message<byte[]> message = messages.get(0);
+		SimpMessageHeaderAccessor headerAccessor =
+				MessageHeaderAccessor.getAccessor(message, SimpMessageHeaderAccessor.class);
+
+		assertNotNull(headerAccessor);
+		assertEquals(SimpMessageType.MESSAGE, headerAccessor.getMessageType());
+		assertEquals("/prefix/joe/queue/foo", headerAccessor.getDestination());
+	}
+
 	@Test
 	public void convertAndSendWithMutableSimpMessageHeaders() {
 		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.create();