MockHttpInputMessage respects getBody contract

Issue: SPR-16367

Author: rstoyanchev

spring-test/src/main/java/org/springframework/mock/http/MockHttpInputMessage.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -38,7 +38,7 @@ public class MockHttpInputMessage implements HttpInputMessage {
 
 
 	public MockHttpInputMessage(byte[] contents) {
-		this.body = (contents != null ? new ByteArrayInputStream(contents) : null);
+		this.body = new ByteArrayInputStream(contents != null ? contents : new byte[0]);
 	}
 
 	public MockHttpInputMessage(InputStream body) {

spring-test/src/main/java/org/springframework/mock/http/client/MockClientHttpResponse.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -72,10 +72,7 @@ public String getStatusText() throws IOException {
 	@Override
 	public void close() {
 		try {
-			InputStream body = getBody();
-			if (body != null) {
-				body.close();
-			}
+			getBody().close();
 		}
 		catch (IOException ex) {
 			// ignore