Completely custom timeout approach as suggested by dsaff in #727

src/main/java/org/junit/internal/runners/statements/FailOnTimeout.java

@@ -2,7 +2,8 @@
 
 import java.lang.management.ManagementFactory;
 import java.lang.management.ThreadMXBean;
-import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.FutureTask;
@@ -66,30 +67,48 @@ private Throwable getResult(FutureTask<Throwable> task, Thread thread) {
         }
     }
 
-    private Exception createTimeoutException(Thread thread) {
+    protected Throwable createTimeoutException(Thread thread) {
+        List<Throwable> exceptions = new ArrayList<Throwable>();
+
+        exceptions.add(createCurrentThreadException(thread));
+        exceptions.addAll(createAdditionalTimeoutExceptions(thread));
+
+        return exceptions.size() == 1 ? exceptions.get(0) :  new MultipleFailureException(exceptions);
+    }
+
+    private Throwable createCurrentThreadException(Thread thread) {
         StackTraceElement[] stackTrace = thread.getStackTrace();
-        final Thread stuckThread = fLookForStuckThread ? getStuckThread(thread) : null;
         Exception currThreadException = new TestTimedOutException(fTimeout, fTimeUnit);
         if (stackTrace != null) {
             currThreadException.setStackTrace(stackTrace);
             thread.interrupt();
         }
+        return currThreadException;
+    }
+
+    /**
+     * Returns list of optional exceptions with additional timeout failure context like stuck
+     * thread (if there is one detected and detection is enabled); can be overridden to add custom
+     * timeout failure context.
+     */
+    protected List<Throwable> createAdditionalTimeoutExceptions(Thread thread) {
+        List<Throwable> exceptions = new ArrayList<Throwable>();
+
+        final Thread stuckThread = fLookForStuckThread ? getStuckThread(thread) : null;
         if (stuckThread != null) {
-            Exception stuckThreadException = 
-                new Exception ("Appears to be stuck in thread " +
-                               stuckThread.getName());
+            Exception stuckThreadException =
+                    new Exception ("Appears to be stuck in thread " +
+                            stuckThread.getName());
             stuckThreadException.setStackTrace(getStackTrace(stuckThread));
-            return new MultipleFailureException    
-                (Arrays.<Throwable>asList(currThreadException, stuckThreadException));
-        } else {
-            return currThreadException;
+            exceptions.add(stuckThreadException);
         }
+        return exceptions;
     }
 
     /**
      * Retrieves the stack trace for a given thread.
      * @param thread The thread whose stack is to be retrieved.
-     * @return The stack trace; returns a zero-length array if the thread has 
+     * @return The stack trace; returns a zero-length array if the thread has
      * terminated or the stack cannot be retrieved for some other reason.
      */
     private StackTraceElement[] getStackTrace(Thread thread) {
@@ -107,18 +126,18 @@ private StackTraceElement[] getStackTrace(Thread thread) {
      * @param mainThread The main thread created by {@code evaluate()}
      * @return The thread which appears to be causing the problem, if different from
      * {@code mainThread}, or {@code null} if the main thread appears to be the
-     * problem or if the thread cannot be determined.  The return value is never equal 
+     * problem or if the thread cannot be determined.  The return value is never equal
      * to {@code mainThread}.
      */
     private Thread getStuckThread (Thread mainThread) {
-        if (fThreadGroup == null) 
+        if (fThreadGroup == null)
             return null;
         Thread[] threadsInGroup = getThreadArray(fThreadGroup);
-        if (threadsInGroup == null) 
+        if (threadsInGroup == null)
             return null;
-        
+
         // Now that we have all the threads in the test's thread group: Assume that
-        // any thread we're "stuck" in is RUNNABLE.  Look for all RUNNABLE threads. 
+        // any thread we're "stuck" in is RUNNABLE.  Look for all RUNNABLE threads.
         // If just one, we return that (unless it equals threadMain).  If there's more
         // than one, pick the one that's using the most CPU time, if this feature is
         // supported.
@@ -131,13 +150,13 @@ private Thread getStuckThread (Thread mainThread) {
                     stuckThread = thread;
                     maxCpuTime = threadCpuTime;
                 }
-            }               
+            }
         }
         return (stuckThread == mainThread) ? null : stuckThread;
     }
 
     /**
-     * Returns all active threads belonging to a thread group.  
+     * Returns all active threads belonging to a thread group.
      * @param group The thread group.
      * @return The active threads in the thread group.  The result should be a
      * complete list of the active threads at some point in time.  Returns {@code null}
@@ -158,16 +177,16 @@ private Thread[] getThreadArray(ThreadGroup group) {
             // is >= the array's length; therefore we can't trust that it returned all
             // the threads.  Try again.
             enumSize += 100;
-            if (++loopCount >= 5) 
+            if (++loopCount >= 5)
                 return null;
-            // threads are proliferating too fast for us.  Bail before we get into 
+            // threads are proliferating too fast for us.  Bail before we get into
             // trouble.
         }
         return copyThreads(threads, enumCount);
     }
 
     /**
-     * Returns an array of the first {@code count} Threads in {@code threads}. 
+     * Returns an array of the first {@code count} Threads in {@code threads}.
      * (Use instead of Arrays.copyOf to maintain compatibility with Java 1.5.)
      * @param threads The source array.
      * @param count The maximum length of the result array.

src/main/java/org/junit/rules/Timeout.java

@@ -100,6 +100,18 @@ public static Timeout seconds(long seconds) {
         return new Timeout(seconds, TimeUnit.SECONDS);
     }
 
+    protected final long getTimeout() {
+        return fTimeout;
+    }
+
+    protected final TimeUnit getTimeUnit() {
+        return fTimeUnit;
+    }
+
+    protected final boolean isLookForStuckThread() {
+        return fLookForStuckThread;
+    }
+
     /**
      * Specifies whether to look for a stuck thread.  If a timeout occurs and this
      * feature is enabled, the test will look for a thread that appears to be stuck

src/test/java/org/junit/tests/AllTests.java

@@ -91,6 +91,7 @@
 import org.junit.tests.running.core.JUnitCoreReturnsCorrectExitCodeTest;
 import org.junit.tests.running.core.SystemExitTest;
 import org.junit.tests.running.methods.AnnotationTest;
+import org.junit.tests.running.methods.CustomTimeoutTest;
 import org.junit.tests.running.methods.ExpectedTest;
 import org.junit.tests.running.methods.InheritedTestTest;
 import org.junit.tests.running.methods.ParameterizedTestMethodTest;
@@ -130,6 +131,7 @@
         TestMethodTest.class,
         TextListenerTest.class,
         TimeoutTest.class,
+        CustomTimeoutTest.class,
         EnclosedTest.class,
         ParameterizedTestMethodTest.class,
         InitializationErrorForwardCompatibilityTest.class,

src/test/java/org/junit/tests/running/methods/CustomTimeoutTest.java

@@ -0,0 +1,144 @@
+package org.junit.tests.running.methods;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.io.Writer;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.internal.runners.statements.FailOnTimeout;
+import org.junit.rules.TestRule;
+import org.junit.rules.Timeout;
+import org.junit.runner.Description;
+import org.junit.runner.JUnitCore;
+import org.junit.runner.Result;
+import org.junit.runners.model.Statement;
+import org.junit.tests.running.methods.TimeoutTest.InfiniteLoopMultithreaded;
+
+public class CustomTimeoutTest {
+
+    public static class CustomTimeoutHandler {
+
+        public Exception handleTimeout(Thread thread) {
+        	String prefix = "[" + getClass().getSimpleName() + "] ";
+            return new Exception(prefix + "Appears to be stuck due to running into timeout. Here could be some more custom failure context...");
+        }
+
+    }
+
+
+    public static class CustomFailOnTimeout extends FailOnTimeout {
+
+        private CustomTimeoutHandler handler = new CustomTimeoutHandler();
+
+        public CustomFailOnTimeout(Statement base, long timeout,
+                TimeUnit unit, boolean lookForStuckThread) {
+            super(base, timeout, unit, lookForStuckThread);
+        }
+
+        @Override
+        protected List<Throwable> createAdditionalTimeoutExceptions(
+                Thread thread) {
+            List<Throwable> exceptions = super.createAdditionalTimeoutExceptions(thread);
+            Throwable handleTimeout = handler.handleTimeout(thread);
+            exceptions.add(handleTimeout);
+            return exceptions;
+        }
+
+    }
+
+    public static class CustomTimeout extends Timeout {
+
+        public CustomTimeout(int timeout, TimeUnit unit) {
+            this(timeout, unit, false);
+        }
+
+        public CustomTimeout(int timeout, TimeUnit unit, boolean lookForStuckThread) {
+            super (new Timeout(timeout, unit), lookForStuckThread);
+        }
+
+        @Override
+        public Statement apply(Statement base, Description description) {
+            return new CustomFailOnTimeout(base, getTimeout(), getTimeUnit(), isLookForStuckThread());
+        }
+    }
+
+
+    public static class InfiniteLoopTest {
+
+        @Rule
+        public TestRule globalTimeout = new CustomTimeout(100, TimeUnit.MILLISECONDS);
+
+        @Test
+        public void failure() {
+            infiniteLoop();
+        }
+
+        private void infiniteLoop() {
+            for (; ; ) {
+                try {
+                    Thread.sleep(10);
+                } catch (InterruptedException e) {
+                }
+            }
+        }
+    }
+
+    @Test
+    public void infiniteLoop() throws Exception {
+        JUnitCore core = new JUnitCore();
+        Result result = core.run(InfiniteLoopTest.class);
+        assertEquals(1, result.getRunCount());
+        assertEquals(2, result.getFailureCount());
+        Throwable exception[] = new Throwable[2];
+        for (int i = 0; i < 2; i++)
+            exception[i] = result.getFailures().get(i).getException();
+        assertThat(exception[0].getMessage(), containsString("test timed out after 100 milliseconds"));
+        assertThat(exception[1].getMessage(), containsString("[CustomTimeoutHandler] Appears to be stuck due to running into timeout. Here could be some more custom failure context..."));
+    }
+
+
+    // --------------------------------------------------------------------------------------------------
+    // Below is the additional code for test scenario when the timeout is also looking for stuck threads:
+
+    public static class InfiniteLoopWithLookForStuckThreadTest {
+
+        @Rule
+        public TestRule globalTimeout = new CustomTimeout(100, TimeUnit.MILLISECONDS, true);
+
+        @Test
+        public void failure() throws Exception {
+            (new InfiniteLoopMultithreaded()).failure(false);
+        }
+
+    }
+
+    @Test
+    public void infiniteLoopWithLookForStuckThread() throws Exception {
+        JUnitCore core = new JUnitCore();
+        Result result = core.run(InfiniteLoopWithLookForStuckThreadTest.class);
+        assertEquals(1, result.getRunCount());
+        assertEquals(3, result.getFailureCount());
+        Throwable exception[] = new Throwable[3];
+        for (int i = 0; i < 3; i++)
+            exception[i] = result.getFailures().get(i).getException();
+        assertThat(exception[0].getMessage(), containsString("test timed out after 100 milliseconds"));
+        assertThat(stackForException(exception[0]), containsString("Thread.join"));
+        assertThat(exception[1].getMessage(), containsString("Appears to be stuck in thread timeout-thr2"));
+        assertThat(exception[2].getMessage(), containsString("[CustomTimeoutHandler] Appears to be stuck due to running into timeout. Here could be some more custom failure context..."));
+    }
+
+    private String stackForException(Throwable exception) {
+        Writer buffer = new StringWriter();
+        PrintWriter writer = new PrintWriter(buffer);
+        exception.printStackTrace(writer);
+        return buffer.toString();
+    }
+
+}