Unit tests for @MessageExceptionHandler cause and error resolution

Issue: SPR-16912

spring-messaging/src/test/java/org/springframework/messaging/handler/annotation/support/AnnotationExceptionHandlerMethodResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -86,6 +86,12 @@ public class AnnotationExceptionHandlerMethodResolverTests {
 		assertEquals("handleIOException", this.resolver.resolveMethod(exception).getName());
 	}
 
+	@Test
+	public void resolveMethodAgainstCause() {
+		IllegalStateException exception = new IllegalStateException(new IOException());
+		assertEquals("handleIOException", this.resolver.resolveMethod(exception).getName());
+	}
+
 	@Test(expected = IllegalStateException.class)
 	public void ambiguousExceptionMapping() {
 		new AnnotationExceptionHandlerMethodResolver(AmbiguousController.class);

spring-messaging/src/test/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -75,7 +75,6 @@ import static org.mockito.BDDMockito.*;
  * @author Brian Clozel
  * @author Sebastien Deleuze
  */
-@SuppressWarnings("unused")
 public class SimpAnnotationMethodMessageHandlerTests {
 
 	private static final String TEST_INVALID_VALUE = "invalidValue";
@@ -201,6 +200,30 @@ public class SimpAnnotationMethodMessageHandlerTests {
 		assertEquals("illegalState", handlerMethod.getMethod().getName());
 	}
 
+	@Test
+	public void exceptionAsCause() {
+		Message<?> message = createMessage("/pre/illegalStateCause");
+		this.messageHandler.registerHandler(this.testController);
+		this.messageHandler.handleMessage(message);
+
+		assertEquals("handleExceptionWithHandlerMethodArg", this.testController.method);
+		HandlerMethod handlerMethod = (HandlerMethod) this.testController.arguments.get("handlerMethod");
+		assertNotNull(handlerMethod);
+		assertEquals("illegalStateCause", handlerMethod.getMethod().getName());
+	}
+
+	@Test
+	public void errorAsMessageHandlingException() {
+		Message<?> message = createMessage("/pre/error");
+		this.messageHandler.registerHandler(this.testController);
+		this.messageHandler.handleMessage(message);
+
+		assertEquals("handleErrorWithHandlerMethodArg", this.testController.method);
+		HandlerMethod handlerMethod = (HandlerMethod) this.testController.arguments.get("handlerMethod");
+		assertNotNull(handlerMethod);
+		assertEquals("errorAsThrowable", handlerMethod.getMethod().getName());
+	}
+
 	@Test
 	public void simpScope() {
 		Map<String, Object> sessionAttributes = new ConcurrentHashMap<>();
@@ -412,7 +435,17 @@ public class SimpAnnotationMethodMessageHandlerTests {
 
 		@MessageMapping("/illegalState")
 		public void illegalState() {
-			throw new IllegalStateException();
+			throw new IllegalStateException("my cause");
+		}
+
+		@MessageMapping("/illegalStateCause")
+		public void illegalStateCause() {
+			throw new RuntimeException(new IllegalStateException("my cause"));
+		}
+
+		@MessageMapping("/error")
+		public void errorAsThrowable() {
+			throw new Error("my cause");
 		}
 
 		@MessageExceptionHandler(MethodArgumentNotValidException.class)
@@ -420,10 +453,18 @@ public class SimpAnnotationMethodMessageHandlerTests {
 			this.method = "handleValidationException";
 		}
 
-		@MessageExceptionHandler(IllegalStateException.class)
-		public void handleExceptionWithHandlerMethodArg(HandlerMethod handlerMethod) {
+		@MessageExceptionHandler
+		public void handleExceptionWithHandlerMethodArg(IllegalStateException ex, HandlerMethod handlerMethod) {
 			this.method = "handleExceptionWithHandlerMethodArg";
 			this.arguments.put("handlerMethod", handlerMethod);
+			assertEquals("my cause", ex.getMessage());
+		}
+
+		@MessageExceptionHandler
+		public void handleErrorWithHandlerMethodArg(Error ex, HandlerMethod handlerMethod) {
+			this.method = "handleErrorWithHandlerMethodArg";
+			this.arguments.put("handlerMethod", handlerMethod);
+			assertEquals("my cause", ex.getMessage());
 		}
 
 		@MessageMapping("/scope")
@@ -446,7 +487,6 @@ public class SimpAnnotationMethodMessageHandlerTests {
 
 		private String method;
 
-
 		@MessageMapping("foo")
 		public void handleFoo() {
 			this.method = "handleFoo";