Make sure Servlet 3 bridge is compatible with Servlet 4

[flowersinthesand]

I guess Servlet 4 didn't break backward compatibility so that Servlet 3 bridge should be compatible with Servlet 4. Just to be safe, let's make sure it works.

[flowersinthesand]

I tested this with Undertow 2 and confirmed it works. Here's a diff FYI:

Index: bridge-servlet3/src/test/java/io/cettia/asity/bridge/servlet3/ServletServerHttpExchangeTest.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- bridge-servlet3/src/test/java/io/cettia/asity/bridge/servlet3/ServletServerHttpExchangeTest.java	(date 1528558909000)
+++ bridge-servlet3/src/test/java/io/cettia/asity/bridge/servlet3/ServletServerHttpExchangeTest.java	(date 1528563140075)
@@ -18,18 +18,16 @@
 import io.cettia.asity.action.Action;
 import io.cettia.asity.http.ServerHttpExchange;
 import io.cettia.asity.test.ServerHttpExchangeTestBase;
+import io.undertow.Handlers;
+import io.undertow.Undertow;
+import io.undertow.server.handlers.PathHandler;
+import io.undertow.servlet.Servlets;
+import io.undertow.servlet.api.DeploymentInfo;
+import io.undertow.servlet.api.DeploymentManager;
 import org.eclipse.jetty.client.api.Response;
-import org.eclipse.jetty.server.Server;
-import org.eclipse.jetty.server.ServerConnector;
-import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.junit.Ignore;
 import org.junit.Test;
 
-import javax.servlet.Servlet;
-import javax.servlet.ServletContext;
-import javax.servlet.ServletContextEvent;
-import javax.servlet.ServletContextListener;
-import javax.servlet.ServletRegistration;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -38,36 +36,38 @@
  */
 public class ServletServerHttpExchangeTest extends ServerHttpExchangeTestBase {
 
-  private Server server;
+  private static Action<ServerHttpExchange> requestAction;
 
+  private Undertow server;
+
   @Override
-  protected void startServer(int port, final Action<ServerHttpExchange> requestAction) throws
-    Exception {
-    server = new Server();
-    ServerConnector connector = new ServerConnector(server);
-    connector.setPort(port);
-    server.addConnector(connector);
-    ServletContextHandler handler = new ServletContextHandler();
-    handler.addEventListener(new ServletContextListener() {
-      @Override
-      public void contextInitialized(ServletContextEvent event) {
-        ServletContext context = event.getServletContext();
-        Servlet servlet = new AsityServlet().onhttp(requestAction);
-        ServletRegistration.Dynamic reg = context.addServlet(AsityServlet.class.getName(), servlet);
-        reg.setAsyncSupported(true);
-        reg.addMapping(TEST_URI);
-      }
+  protected void startServer(int port, Action<ServerHttpExchange> requestAction) throws Exception {
+    ServletServerHttpExchangeTest.requestAction = requestAction;
+    DeploymentInfo servletBuilder = Servlets.deployment()
+      .setClassLoader(ServletServerHttpExchangeTest.class.getClassLoader())
+      .setContextPath("/")
+      .setDeploymentName("test.war")
+      .addServlets(Servlets.servlet(UndertowAsityServlet.class.getName(), UndertowAsityServlet.class).addMapping(TEST_URI).setAsyncSupported(true));
 
-      @Override
-      public void contextDestroyed(ServletContextEvent sce) {
-      }
-    });
-    server.setHandler(handler);
+    DeploymentManager manager = Servlets.defaultContainer().addDeployment(servletBuilder);
+    manager.deploy();
+    PathHandler path = Handlers.path(manager.start());
+
+    server = Undertow.builder()
+      .addHttpListener(port, "localhost")
+      .setHandler(path)
+      .build();
     server.start();
   }
 
+  private static class UndertowAsityServlet extends AsityServlet {
+    public UndertowAsityServlet() {
+      onhttp(requestAction);
+    }
+  }
+
   @Override
-  protected void stopServer() throws Exception {
+  protected void stopServer() {
     server.stop();
   }
 
Index: bridge-servlet3/pom.xml
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- bridge-servlet3/pom.xml	(date 1528558909000)
+++ bridge-servlet3/pom.xml	(date 1528562704863)
@@ -51,6 +51,7 @@
     <dependency>
       <groupId>javax.servlet</groupId>
       <artifactId>javax.servlet-api</artifactId>
+      <version>4.0.1</version>
     </dependency>
     <dependency>
       <groupId>org.eclipse.jetty</groupId>
@@ -59,6 +60,16 @@
     <dependency>
       <groupId>org.eclipse.jetty.websocket</groupId>
       <artifactId>javax-websocket-server-impl</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>io.undertow</groupId>
+      <artifactId>undertow-core</artifactId>
+      <version>2.0.1.Final</version>
+    </dependency>
+    <dependency>
+      <groupId>io.undertow</groupId>
+      <artifactId>undertow-servlet</artifactId>
+      <version>2.0.1.Final</version>
     </dependency>
   </dependencies>
 </project>