Issue #7086 - add test for failures from WebSocketCoreSession.demand()

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>

jetty-websocket/websocket-core-tests/src/test/java/org/eclipse/jetty/websocket/core/DemandTest.java

@@ -0,0 +1,148 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2021 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.websocket.core;
+
+import java.net.URI;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.FutureCallback;
+import org.eclipse.jetty.websocket.core.client.WebSocketCoreClient;
+import org.eclipse.jetty.websocket.core.server.WebSocketNegotiator;
+import org.eclipse.jetty.websocket.core.server.WebSocketUpgradeHandler;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class DemandTest
+{
+    Server _server;
+    ServerConnector _connector;
+    WebSocketCoreClient _client;
+
+    @BeforeEach
+    public void before() throws Exception
+    {
+        _server = new Server();
+        _connector = new ServerConnector(_server);
+        _server.addConnector(_connector);
+
+        WebSocketUpgradeHandler upgradeHandler = new WebSocketUpgradeHandler();
+        _server.setHandler(upgradeHandler);
+        upgradeHandler.addMapping("/", WebSocketNegotiator.from((neg) -> new EchoFrameHandler()));
+        _server.start();
+
+        _client = new WebSocketCoreClient();
+        _client.start();
+    }
+
+    @AfterEach
+    public void after() throws Exception
+    {
+        _client.stop();
+        _server.stop();
+    }
+
+    public static class AbstractFrameHandler implements FrameHandler
+    {
+        protected CoreSession _coreSession;
+
+        @Override
+        public void onOpen(CoreSession coreSession, Callback callback)
+        {
+            _coreSession = coreSession;
+            callback.succeeded();
+            coreSession.demand(1);
+        }
+
+        @Override
+        public void onFrame(Frame frame, Callback callback)
+        {
+            callback.succeeded();
+            _coreSession.demand(1);
+        }
+
+        @Override
+        public void onError(Throwable cause, Callback callback)
+        {
+            callback.succeeded();
+            _coreSession.demand(1);
+        }
+
+        @Override
+        public void onClosed(CloseStatus closeStatus, Callback callback)
+        {
+            callback.succeeded();
+        }
+
+        @Override
+        public boolean isDemanding()
+        {
+            return true;
+        }
+    }
+
+    @Test
+    public void testDemandAfterClose() throws Exception
+    {
+        CountDownLatch closed = new CountDownLatch(1);
+        CompletableFuture<Throwable> errorFuture = new CompletableFuture<>();
+        AbstractFrameHandler frameHandler = new AbstractFrameHandler()
+        {
+            @Override
+            public void onFrame(Frame frame, Callback callback)
+            {
+                try
+                {
+                    // Fail the core session so it is completely closed.
+                    FutureCallback futureCallback = new FutureCallback();
+                    _coreSession.close(CloseStatus.BAD_PAYLOAD, "bad data", futureCallback);
+                    futureCallback.block();
+                    _coreSession.abort();
+
+                    // Demand should not throw even if closed.
+                    _coreSession.demand(1);
+                    errorFuture.complete(null);
+                }
+                catch (Throwable t)
+                {
+                    errorFuture.complete(t);
+                }
+            }
+
+            @Override
+            public void onClosed(CloseStatus closeStatus, Callback callback)
+            {
+                super.onClosed(closeStatus, callback);
+                closed.countDown();
+            }
+        };
+
+        URI uri = URI.create("ws://localhost:" + _connector.getLocalPort());
+        CoreSession coreSession = _client.connect(frameHandler, uri).get(5, TimeUnit.SECONDS);
+        coreSession.sendFrame(new Frame(OpCode.TEXT, "hello world"), Callback.NOOP, false);
+        assertTrue(closed.await(5, TimeUnit.SECONDS));
+
+        // There should be no error from the frame handler.
+        Throwable error = errorFuture.get(5, TimeUnit.SECONDS);
+        assertNull(error);
+    }
+}