Add TestAlpnFallback

Author: dsoumis

test/org/apache/tomcat/util/net/TestAlpnFallback.java

@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.tomcat.util.net;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import org.apache.catalina.Context;
+import org.apache.catalina.startup.Tomcat;
+import org.apache.coyote.http2.Http2TestBase;
+import org.apache.tomcat.util.buf.ByteChunk;
+
+public class TestAlpnFallback extends Http2TestBase {
+
+    @Test
+    public void testAlpnFallbackToHttp11() throws Exception {
+        TesterSupport.configureClientSsl();
+        //There's no ALPN negotiation without TLS
+        enableHttp2(true);
+
+        Tomcat tomcat = getTomcatInstance();
+
+        Context ctx = getProgrammaticRootContext();
+        Tomcat.addServlet(ctx, "snoop", new SnoopServlet());
+        ctx.addServletMappingDecoded("/", "snoop");
+
+        tomcat.start();
+
+        // HttpURLConnection does not support ALPN, so this request will connect over TLS without negotiating h2.
+        // The connector must fall back to HTTP/1.1 rather than dropping the connection.
+        ByteChunk res = new ByteChunk();
+        getUrl("https://localhost:" + getPort() + "/", res, null);
+        RequestDescriptor requestDesc = SnoopResult.parse(res.toString());
+        Assert.assertEquals("HTTP/1.1", requestDesc.getRequestInfo("REQUEST-PROTOCOL"));
+    }
+
+}

test/org/apache/tomcat/util/net/TesterSupport.java

@@ -128,7 +128,7 @@ public static boolean isTlsv13Available() {
     }
 
     public static void initSsl(Tomcat tomcat) {
-        // By default, use JSSE JSSE trust
+        // By default, use JSSE trust
         initSsl(tomcat, false);
     }