Add TimedOutTestsListener to print the full thread dump on test timeout

pom.xml

@@ -72,6 +72,12 @@
       <artifactId>checkstyle</artifactId>
       <version>5.6</version>
     </dependency>
+
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.12</version>
+    </dependency>
   </dependencies>
 
   <build>

src/main/java/io/netty/build/junit/TimedOutTestsListener.java

@@ -0,0 +1,192 @@
+/*
+ * Copyright 2016 The Netty Project
+ *
+ * The Netty Project 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.
+ */
+/**
+ * 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 io.netty.build.junit;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.lang.management.LockInfo;
+import java.lang.management.ManagementFactory;
+import java.lang.management.MonitorInfo;
+import java.lang.management.ThreadInfo;
+import java.lang.management.ThreadMXBean;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.Map;
+
+import org.junit.runner.notification.Failure;
+import org.junit.runner.notification.RunListener;
+
+/**
+ * JUnit run listener which prints full thread dump into System.err
+ * in case a test is failed due to timeout.
+ */
+public class TimedOutTestsListener extends RunListener {
+
+    private static final String TEST_TIMED_OUT_PREFIX = "test timed out after";
+
+    private static final String INDENT = "\t";
+
+    private final PrintWriter output;
+
+    public TimedOutTestsListener() {
+        this.output = new PrintWriter(System.err);
+    }
+
+    public TimedOutTestsListener(PrintWriter output) {
+        this.output = output;
+    }
+
+    @Override
+    public void testFailure(Failure failure) throws Exception {
+        if (failure != null && failure.getMessage() != null
+                && failure.getMessage().startsWith(TEST_TIMED_OUT_PREFIX)) {
+            output.println("====> TEST TIMED OUT. PRINTING THREAD DUMP. <====");
+            output.println();
+            output.print(buildThreadDiagnosticString());
+            output.flush();
+        }
+    }
+
+    public static String buildThreadDiagnosticString() {
+        StringWriter sw = new StringWriter();
+        PrintWriter output = new PrintWriter(sw);
+
+        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss,SSS", Locale.US);
+        output.println(String.format("Timestamp: %s", dateFormat.format(new Date())));
+        output.println();
+        output.println(buildThreadDump());
+
+        String deadlocksInfo = buildDeadlockInfo();
+        if (deadlocksInfo != null) {
+            output.println("====> DEADLOCKS DETECTED <====");
+            output.println();
+            output.println(deadlocksInfo);
+        }
+
+        return sw.toString();
+    }
+
+    static String buildThreadDump() {
+        StringBuilder dump = new StringBuilder();
+        Map<Thread, StackTraceElement[]> stackTraces = Thread.getAllStackTraces();
+        for (Map.Entry<Thread, StackTraceElement[]> e : stackTraces.entrySet()) {
+            Thread thread = e.getKey();
+            dump.append(String.format(
+                    "\"%s\" %s prio=%d tid=%d %s\njava.lang.Thread.State: %s",
+                    thread.getName(),
+                    thread.isDaemon() ? "daemon" : "",
+                    thread.getPriority(),
+                    thread.getId(),
+                    Thread.State.WAITING.equals(thread.getState()) ?
+                            "in Object.wait()" :
+                            (thread.getState().name() == null ? "" : thread.getState().name().toLowerCase()),
+                    Thread.State.WAITING.equals(thread.getState()) ?
+                            "WAITING (on object monitor)" : thread.getState()));
+            for (StackTraceElement stackTraceElement : e.getValue()) {
+                dump.append("\n\tat ");
+                dump.append(stackTraceElement);
+            }
+            dump.append('\n');
+        }
+        return dump.toString();
+    }
+
+    static String buildDeadlockInfo() {
+        ThreadMXBean threadBean = ManagementFactory.getThreadMXBean();
+        long[] threadIds = threadBean.findMonitorDeadlockedThreads();
+        if (threadIds == null || threadIds.length == 0) {
+            return null;
+        }
+        StringWriter stringWriter = new StringWriter();
+        PrintWriter out = new PrintWriter(stringWriter);
+
+        ThreadInfo[] infos = threadBean.getThreadInfo(threadIds, true, true);
+        for (ThreadInfo ti : infos) {
+            printThreadInfo(ti, out);
+            printLockInfo(ti.getLockedSynchronizers(), out);
+            out.println();
+        }
+
+        out.close();
+        return stringWriter.toString();
+    }
+
+    private static void printThreadInfo(ThreadInfo ti, PrintWriter out) {
+        // print thread information
+        printThread(ti, out);
+
+        // print stack trace with locks
+        StackTraceElement[] stacktrace = ti.getStackTrace();
+        MonitorInfo[] monitors = ti.getLockedMonitors();
+        for (int i = 0; i < stacktrace.length; i++) {
+            StackTraceElement ste = stacktrace[i];
+            out.println(INDENT + "at " + ste.toString());
+            for (MonitorInfo mi : monitors) {
+                if (mi.getLockedStackDepth() == i) {
+                    out.println(INDENT + "  - locked " + mi);
+                }
+            }
+        }
+        out.println();
+    }
+
+    private static void printThread(ThreadInfo ti, PrintWriter out) {
+        out.print("\"" + ti.getThreadName() + "\"" + " Id="
+                + ti.getThreadId() + " in " + ti.getThreadState());
+        if (ti.getLockName() != null) {
+            out.print(" on lock=" + ti.getLockName());
+        }
+        if (ti.isSuspended()) {
+            out.print(" (suspended)");
+        }
+        if (ti.isInNative()) {
+            out.print(" (running in native)");
+        }
+        out.println();
+        if (ti.getLockOwnerName() != null) {
+            out.println(INDENT + " owned by " + ti.getLockOwnerName() + " Id="
+                    + ti.getLockOwnerId());
+        }
+    }
+
+    private static void printLockInfo(LockInfo[] locks, PrintWriter out) {
+        out.println(INDENT + "Locked synchronizers: count = " + locks.length);
+        for (LockInfo li : locks) {
+            out.println(INDENT + "  - " + li);
+        }
+        out.println();
+    }
+
+}