INT-1382 added tests for DynamicExpression-based transformer, and the default bean name for the ExpressionSource instance is now defined in the XSD as 'expressionSource'

spring-integration-core/src/main/resources/org/springframework/integration/config/xml/spring-integration-2.0.xsd

@@ -2383,7 +2383,7 @@ Name of the header whose value to use.
 				</xsd:documentation>
 			</xsd:annotation>
 		</xsd:attribute>
-		<xsd:attribute name="source" type="xsd:string" use="required">
+		<xsd:attribute name="source" type="xsd:string" default="expressionSource">
 			<xsd:annotation>
 				<xsd:documentation>
 					The reference to an ExpressionSource.

spring-integration-core/src/test/java/org/springframework/integration/transformer/DynamicExpressionTransformerIntegrationTests-context.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans:beans xmlns="http://www.springframework.org/schema/integration"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:beans="http://www.springframework.org/schema/beans"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans
+			http://www.springframework.org/schema/beans/spring-beans.xsd
+			http://www.springframework.org/schema/integration
+			http://www.springframework.org/schema/integration/spring-integration.xsd">
+
+	<channel id="output">
+		<queue/>
+	</channel>
+
+	<transformer input-channel="input" output-channel="output">
+		<expression key="test.transform"/>
+	</transformer>
+
+	<beans:bean id="expressionSource" class="org.springframework.integration.expression.ReloadableResourceBundleExpressionSource">
+		<beans:property name="basename" value="org/springframework/integration/transformer/expressions"/>
+	</beans:bean>
+
+</beans:beans>

spring-integration-core/src/test/java/org/springframework/integration/transformer/DynamicExpressionTransformerIntegrationTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2002-2010 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.transformer;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.integration.Message;
+import org.springframework.integration.MessageChannel;
+import org.springframework.integration.core.PollableChannel;
+import org.springframework.integration.support.MessageBuilder;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+/**
+ * @author Mark Fisher
+ */
+@ContextConfiguration
+@RunWith(SpringJUnit4ClassRunner.class)
+public class DynamicExpressionTransformerIntegrationTests {
+
+	@Autowired
+	private MessageChannel input;
+
+	@Autowired
+	private PollableChannel output;
+
+
+	@Test
+	public void transformWithDynamicExpression() {
+		Message<?> message = MessageBuilder.withPayload(new TestBean()).setHeader("bar", 123).build();
+		this.input.send(message);
+		Message<?> result = output.receive(0);
+		assertEquals("test123", result.getPayload());
+	}
+
+
+	static class TestBean {
+
+		public String getFoo() {
+			return "test";
+		}
+	}
+
+}

spring-integration-core/src/test/java/org/springframework/integration/transformer/expressions.properties

@@ -0,0 +1 @@
+test.transform=payload.foo + headers.bar