added test for @Payload annotation with SpEL on a Gateway

spring-integration-core/src/test/java/org/springframework/integration/gateway/GatewayWithPayloadExpressionTests-context.xml

@@ -12,6 +12,10 @@
 		<int:method name="send2" request-channel="input" payload-expression="@testBean.sum(#args[0])"/>
 	</int:gateway>
 
+	<int:gateway id="annotatedGateway"
+				 service-interface="org.springframework.integration.gateway.GatewayWithPayloadExpressionTests.SampleAnnotatedGateway"
+				 default-request-channel="input"/>
+
 	<int:channel id="input">
 		<int:queue/>
 	</int:channel>

spring-integration-core/src/test/java/org/springframework/integration/gateway/GatewayWithPayloadExpressionTests.java

@@ -23,6 +23,7 @@ import org.junit.runner.RunWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.integration.Message;
+import org.springframework.integration.annotation.Payload;
 import org.springframework.integration.core.PollableChannel;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -38,6 +39,9 @@ public class GatewayWithPayloadExpressionTests {
 	@Autowired
 	private SampleGateway gateway;
 
+	@Autowired
+	private SampleAnnotatedGateway annotatedGateway;
+
 	@Autowired
 	private PollableChannel input;
 
@@ -56,6 +60,13 @@ public class GatewayWithPayloadExpressionTests {
 		assertEquals(324, result.getPayload());
 	}
 
+	@Test
+	public void payloadAnnotationExpression() throws Exception {
+		annotatedGateway.send("foo", "bar");
+		Message<?> result = input.receive(0);
+		assertEquals("foobar", result.getPayload());
+	}
+
 
 	public static interface SampleGateway {
 
@@ -65,6 +76,14 @@ public class GatewayWithPayloadExpressionTests {
 	}
 
 
+	public static interface SampleAnnotatedGateway {
+
+		@Payload("#args[0] + #args[1]")
+		void send(String value1, String value2);
+
+	}
+
+
 	public static class TestBean {
 
 		public int sum(String s) {