Add Tomcat X-Forwarded-For header tests

Update Abstract & Tomcat EmbeddedServletContainerFactoryTests to check
that X-Forwarded-For headers work as expected.

See gh-4018

spring-boot/src/test/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactoryTests.java

@@ -638,8 +638,9 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 		return "http://localhost:" + port + resourcePath;
 	}
 
-	protected String getResponse(String url) throws IOException, URISyntaxException {
-		ClientHttpResponse response = getClientResponse(url);
+	protected String getResponse(String url, String... headers) throws IOException,
+			URISyntaxException {
+		ClientHttpResponse response = getClientResponse(url, headers);
 		try {
 			return StreamUtils.copyToString(response.getBody(), Charset.forName("UTF-8"));
 		}
@@ -649,9 +650,9 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 	}
 
 	protected String getResponse(String url,
-			HttpComponentsClientHttpRequestFactory requestFactory) throws IOException,
-			URISyntaxException {
-		ClientHttpResponse response = getClientResponse(url, requestFactory);
+			HttpComponentsClientHttpRequestFactory requestFactory, String... headers)
+			throws IOException, URISyntaxException {
+		ClientHttpResponse response = getClientResponse(url, requestFactory, headers);
 		try {
 			return StreamUtils.copyToString(response.getBody(), Charset.forName("UTF-8"));
 		}
@@ -660,8 +661,8 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 		}
 	}
 
-	protected ClientHttpResponse getClientResponse(String url) throws IOException,
-			URISyntaxException {
+	protected ClientHttpResponse getClientResponse(String url, String... headers)
+			throws IOException, URISyntaxException {
 		return getClientResponse(url, new HttpComponentsClientHttpRequestFactory() {
 
 			@Override
@@ -669,19 +670,32 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 				return AbstractEmbeddedServletContainerFactoryTests.this.httpClientContext;
 			}
 
-		});
+		}, headers);
 	}
 
 	protected ClientHttpResponse getClientResponse(String url,
-			HttpComponentsClientHttpRequestFactory requestFactory) throws IOException,
-			URISyntaxException {
+			HttpComponentsClientHttpRequestFactory requestFactory, String... headers)
+			throws IOException, URISyntaxException {
 		ClientHttpRequest request = requestFactory.createRequest(new URI(url),
 				HttpMethod.GET);
 		request.getHeaders().add("Cookie", "JSESSIONID=" + "123");
+		for (String header : headers) {
+			String[] parts = header.split(":");
+			request.getHeaders().add(parts[0], parts[1]);
+		}
 		ClientHttpResponse response = request.execute();
 		return response;
 	}
 
+	protected void assertForwardHeaderIsUsed(EmbeddedServletContainerFactory factory)
+			throws IOException, URISyntaxException {
+		this.container = factory.getEmbeddedServletContainer(new ServletRegistrationBean(
+				new ExampleServlet(true), "/hello"));
+		this.container.start();
+		assertThat(getResponse(getLocalUrl("/hello"), "X-Forwarded-For:140.211.11.130"),
+				containsString("remoteaddr=140.211.11.130"));
+	}
+
 	protected abstract AbstractEmbeddedServletContainerFactory getFactory();
 
 	protected abstract Object getJspServlet();

spring-boot/src/test/java/org/springframework/boot/context/embedded/ExampleServlet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -47,6 +47,7 @@ public class ExampleServlet extends GenericServlet {
 		String content = "Hello World";
 		if (this.echoRequestInfo) {
 			content += " scheme=" + request.getScheme();
+			content += " remoteaddr=" + request.getRemoteAddr();
 		}
 		response.getWriter().write(content);
 	}

spring-boot/src/test/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactoryTests.java

@@ -35,6 +35,7 @@ import org.apache.catalina.Valve;
 import org.apache.catalina.Wrapper;
 import org.apache.catalina.connector.Connector;
 import org.apache.catalina.startup.Tomcat;
+import org.apache.catalina.valves.RemoteIpValve;
 import org.apache.coyote.http11.AbstractHttp11JsseProtocol;
 import org.junit.Test;
 import org.mockito.InOrder;
@@ -333,6 +334,13 @@ public class TomcatEmbeddedServletContainerFactoryTests extends
 		assertThat(jspServlet.findInitParameter("a"), is(equalTo("alpha")));
 	}
 
+	@Test
+	public void useForwardHeaders() throws Exception {
+		TomcatEmbeddedServletContainerFactory factory = getFactory();
+		factory.addContextValves(new RemoteIpValve());
+		assertForwardHeaderIsUsed(factory);
+	}
+
 	@Override
 	protected Wrapper getJspServlet() {
 		Container context = ((TomcatEmbeddedServletContainer) this.container).getTomcat()