ACTIVEMQ6-55: add a test of the listener method throwing the NPE

activemq-protocols/activemq-proton-plug/src/main/java/org/proton/plug/context/AbstractConnectionContext.java

@@ -47,12 +47,13 @@ public abstract class AbstractConnectionContext extends ProtonInitializable impl
 
    private final Map<Session, AbstractProtonSessionContext> sessions = new ConcurrentHashMap<>();
 
+   protected LocalListener listener = new LocalListener();
 
    public AbstractConnectionContext(AMQPConnectionCallback connectionCallback)
    {
       this.connectionCallback = connectionCallback;
       connectionCallback.setConnection(this);
-      handler.addEventHandler(new LocalListener());
+      handler.addEventHandler(listener);
    }
 
    public SASLResult getSASLResult()

activemq-protocols/activemq-proton-plug/src/test/java/org/proton/plug/context/AbstractConnectionContextTest.java

@@ -0,0 +1,114 @@
+/**
+ * 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.proton.plug.context;
+
+import io.netty.buffer.ByteBuf;
+
+import org.apache.qpid.proton.engine.Connection;
+import org.apache.qpid.proton.engine.Link;
+import org.apache.qpid.proton.engine.Session;
+import org.junit.Test;
+import org.proton.plug.AMQPConnectionCallback;
+import org.proton.plug.AMQPConnectionContext;
+import org.proton.plug.AMQPSessionCallback;
+import org.proton.plug.ServerSASL;
+import org.proton.plug.exceptions.ActiveMQAMQPException;
+import org.proton.plug.handler.EventHandler;
+
+public class AbstractConnectionContextTest
+{
+
+   @Test
+   public void testListenerDoesntThrowNPEWhenClosingLinkWithNullContext() throws Exception
+   {
+      TestConnectionContext connectionContext = new TestConnectionContext(new TestConnectionCallback());
+      EventHandler listener = connectionContext.getListener();
+
+      Connection protonConnection = Connection.Factory.create();
+      Session protonSession = protonConnection.session();
+      Link link = protonSession.receiver("link");
+
+      link.setContext(null);
+
+      listener.onRemoteClose(link);
+   }
+
+   private class TestConnectionContext extends AbstractConnectionContext
+   {
+
+      public TestConnectionContext(AMQPConnectionCallback connectionCallback)
+      {
+         super(connectionCallback);
+      }
+
+      @Override
+      protected void remoteLinkOpened(Link link) throws Exception
+      {
+
+      }
+
+      @Override
+      protected AbstractProtonSessionContext newSessionExtension(Session realSession) throws ActiveMQAMQPException
+      {
+         return null;
+      }
+
+      public EventHandler getListener()
+      {
+         return listener;
+      }
+   }
+
+   private class TestConnectionCallback implements AMQPConnectionCallback
+   {
+      @Override
+      public void close()
+      {
+
+      }
+
+      @Override
+      public void onTransport(ByteBuf bytes, AMQPConnectionContext connection)
+      {
+
+      }
+
+      @Override
+      public AMQPSessionCallback createSessionCallback(AMQPConnectionContext connection)
+      {
+         return null;
+      }
+
+      @Override
+      public void setConnection(AMQPConnectionContext connection)
+      {
+
+      }
+
+      @Override
+      public AMQPConnectionContext getConnection()
+      {
+         return null;
+      }
+
+      @Override
+      public ServerSASL[] getSASLMechnisms()
+      {
+         return null;
+      }
+   }
+}