diff --git a/modules/beast_core/thread/beast_CallQueue.cpp b/modules/beast_core/thread/beast_CallQueue.cpp
index 438c6beec..98ddfcd33 100644
--- a/modules/beast_core/thread/beast_CallQueue.cpp
+++ b/modules/beast_core/thread/beast_CallQueue.cpp
@@ -151,3 +151,155 @@ bool CallQueue::doSynchronize ()
 
     return did_something;
 }
+
+//------------------------------------------------------------------------------
+
+class CallQueueTests : public UnitTest
+{
+public:
+    enum
+    {
+        callsPerThread = 50000
+    };
+
+    struct TestQueue : CallQueue
+    {
+        explicit TestQueue (Thread& thread)
+            : CallQueue (thread.getThreadName())
+            , m_thread (thread)
+        {
+        }
+        
+        void synchronize ()
+        {
+            CallQueue::synchronize();
+        }
+
+        void signal ()
+        {
+            m_thread.notify ();
+        }
+
+        void reset ()
+        {
+        }
+
+        void close ()
+        {
+            CallQueue::close();
+        }
+
+        Thread& m_thread;
+    };
+
+    struct TestThread : Thread
+    {
+        explicit TestThread (int id)
+            : Thread ("#" + String::fromNumber (id))
+            , m_queue (*this)
+        {
+            startThread ();
+        }
+
+        void stop ()
+        {
+            m_queue.call (&TestThread::doStop, this);
+            m_queue.close ();
+        }
+
+        void doStop ()
+        {
+            signalThreadShouldExit ();
+            notify ();
+        }
+
+        void func1 ()
+        {
+            m_string = m_string + String::fromNumber (m_random.nextInt(10));
+            if (m_string.length() > 100)
+                m_string = String::empty;
+        }
+
+        void func2 ()
+        {
+            m_string = m_string + String::fromNumber (m_random.nextInt());
+            if (m_string.length() > 100)
+                m_string = String::empty;
+        }
+
+        void func3 ()
+        {
+            m_string = m_string + m_string;
+            if (m_string.length() > 100)
+                m_string = m_string.substring (m_random.nextInt (30));
+        }
+
+        void run ()
+        {
+            while (! threadShouldExit ())
+            {
+                wait ();
+
+                m_queue.synchronize();
+            }
+        }
+
+        Random m_random;
+        TestQueue m_queue;
+        String m_string;
+    };
+
+    void testThreads (std::size_t nThreads)
+    {
+        beginTestCase (String::fromNumber (nThreads) + " threads");
+
+        OwnedArray <TestThread> threads;
+        threads.ensureStorageAllocated (nThreads);
+
+        for (std::size_t i = 0; i < nThreads; ++i)
+            threads.add (new TestThread (i + 1));
+
+        Time const startTime (Time::getCurrentTime());
+        
+        for (std::size_t i = 0; i < callsPerThread * nThreads; ++i)
+        {
+            int const n (random().nextInt (threads.size()));
+            int const f (random().nextInt (3));
+            switch (f)
+            {
+            default:
+                bassertfalse;
+            case 0: threads[n]->m_queue.call (&TestThread::func1, threads[n]); break;
+            case 1: threads[n]->m_queue.call (&TestThread::func2, threads[n]); break;
+            case 2: threads[n]->m_queue.call (&TestThread::func3, threads[n]); break;
+            };
+        }
+
+        for (std::size_t i = 0; i < threads.size(); ++i)
+            threads[i]->stop ();
+        
+        for (std::size_t i = 0; i < threads.size(); ++i)
+            threads[i]->waitForThreadToExit();
+
+        double const secondsElapsed ((Time::getCurrentTime() - startTime).inSeconds ());
+
+        pass ();
+
+        std::size_t const totalCalls (callsPerThread * nThreads);
+        double const callsPerSecond = (totalCalls / secondsElapsed);
+        logMessage (String::fromNumber (callsPerSecond + 0.5, 0) + " calls/second (in " +
+            String::fromNumber (secondsElapsed, 1) + " seconds)");
+    }
+
+    void runTest ()
+    {
+        testThreads (8);
+        testThreads (64);
+    }
+
+    CallQueueTests () : UnitTest ("CallQueue", "beast")
+    {
+    }
+};
+
+static CallQueueTests callQueueTests;
diff --git a/modules/beast_core/thread/beast_ThreadWithCallQueue.cpp b/modules/beast_core/thread/beast_ThreadWithCallQueue.cpp
index be9ccbe60..20dcc0ce3 100644
--- a/modules/beast_core/thread/beast_ThreadWithCallQueue.cpp
+++ b/modules/beast_core/thread/beast_ThreadWithCallQueue.cpp
@@ -165,10 +165,13 @@ public:
     {
         explicit TestThread (int id)
             : ThreadWithCallQueue ("#" + String::fromNumber (id))
+            , interruptedOnce (false)
         {
             start (this);
         }
 
+        bool interruptedOnce;
+
         void threadInit ()
         {
         }
@@ -187,7 +190,10 @@ public:
             {
                 interrupted = interruptionPoint ();
                 if (interrupted)
+                {
+                    interruptedOnce = true;
                     break;
+                }
 
                 s = s + String::fromNumber (m_random.nextInt ());
 
@@ -195,6 +201,8 @@ public:
                     s = String::empty;
             }
 
+            bassert (interrupted);
+
             return interrupted;
         }
 
@@ -243,6 +251,11 @@ public:
             };
         }
 
+        for (int i = 0; i < threads.size(); ++i)
+        {
+            expect (threads[i]->interruptedOnce);
+        }
+
         for (int i = 0; i < threads.size(); ++i)
             threads[i]->stop (false);
         for (int i = 0; i < threads.size(); ++i)