Issue #3444 - Adding testcase about reported issue

+ Works with simple HttpField, but not PreEncodedHttpField

Signed-off-by: Joakim Erdfelt <joakim.erdfelt@gmail.com>

jetty-server/src/test/java/org/eclipse/jetty/server/HttpConfigurationCustomizerTest.java

@@ -0,0 +1,105 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2019 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.server;
+
+import java.io.IOException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.eclipse.jetty.http.HttpField;
+import org.eclipse.jetty.http.HttpScheme;
+import org.eclipse.jetty.http.HttpTester;
+import org.eclipse.jetty.server.handler.AbstractHandler;
+import org.eclipse.jetty.server.handler.ContextHandler;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
+
+public class HttpConfigurationCustomizerTest
+{
+    private Server server;
+    private LocalConnector localConnector;
+
+    @BeforeEach
+    public void startServer() throws Exception
+    {
+        server = new Server();
+
+        HttpConnectionFactory http = new HttpConnectionFactory();
+        http.getHttpConfiguration().setSecurePort(9999);
+        http.getHttpConfiguration().setSecureScheme("https");
+
+        HttpConnectionFactory https = new HttpConnectionFactory(http.getHttpConfiguration());
+        https.getHttpConfiguration().addCustomizer((connector, channelConfig, request) -> {
+            // INVALID: final PreEncodedHttpField X_XSS_PROTECTION_FIELD = new PreEncodedHttpField("X-XSS-Protection", "1; mode=block");
+            final HttpField X_XSS_PROTECTION_FIELD = new HttpField("X-XSS-Protection", "1; mode=block");
+            request.setScheme(HttpScheme.HTTPS.asString());
+            request.setSecure(true);
+            request.getResponse().getHttpFields().add(X_XSS_PROTECTION_FIELD); // test response header
+        });
+
+        localConnector = new LocalConnector(server, https);
+        server.addConnector(localConnector);
+
+        ContextHandler context = new ContextHandler();
+        context.setContextPath("/ctx");
+
+        context.setHandler(new AbstractHandler()
+        {
+            @Override
+            public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException
+            {
+                response.setStatus(200);
+                response.getWriter().print("Success");
+                baseRequest.setHandled(true);
+            }
+        });
+
+        server.setHandler(context);
+        server.start();
+    }
+
+    @AfterEach
+    public void stopServer() throws Exception
+    {
+        server.stop();
+    }
+
+    @Test
+    public void testCustomizer() throws Exception
+    {
+        String request = "GET /ctx/ HTTP/1.1\r\n" +
+                "Host: local\r\n" +
+                "Connection: close\r\n" +
+                "\r\n";
+
+        String rawResponse = localConnector.getResponse(request);
+        System.out.println(rawResponse);
+        HttpTester.Response response = HttpTester.parseResponse(rawResponse);
+        assertThat("Response status", response.getStatus(), is(200));
+        assertThat("Response body", response.getContent(), containsString("Success"));
+
+        String value = response.get("X-XSS-Protection");
+        assertThat("X-XSS-Protection value", value, is("1; mode=block"));
+    }
+}