diff --git a/include/boost/thread/locks.hpp b/include/boost/thread/locks.hpp
index 6e4341ad..abbfd75b 100644
--- a/include/boost/thread/locks.hpp
+++ b/include/boost/thread/locks.hpp
@@ -234,6 +234,12 @@ namespace boost
         {
             try_lock();
         }
+        template<typename TimeDuration>
+        unique_lock(Mutex& m_,TimeDuration const& target_time):
+            m(&m_),is_locked(false)
+        {
+            timed_lock(target_time);
+        }
         unique_lock(Mutex& m_,system_time const& target_time):
             m(&m_),is_locked(false)
         {
diff --git a/test/test_mutex.cpp b/test/test_mutex.cpp
index 2640aca7..8725a8fd 100644
--- a/test/test_mutex.cpp
+++ b/test/test_mutex.cpp
@@ -97,6 +97,86 @@ struct test_trylock
     }
 };
 
+template<typename Mutex>
+struct test_lock_times_out_if_other_thread_has_lock
+{
+    typedef boost::unique_lock<Mutex> Lock;
+    
+    Mutex m;
+    boost::mutex done_mutex;
+    bool done;
+    bool locked;
+    boost::condition_variable done_cond;
+    
+    test_lock_times_out_if_other_thread_has_lock():
+        done(false),locked(false)
+    {}
+
+    void locking_thread()
+    {
+        Lock lock(m,boost::defer_lock);
+        lock.timed_lock(boost::posix_time::milliseconds(50));
+
+        boost::lock_guard<boost::mutex> lk(done_mutex);
+        locked=lock.owns_lock();
+        done=true;
+        done_cond.notify_one();
+    }
+
+    void locking_thread_through_constructor()
+    {
+        Lock lock(m,boost::posix_time::milliseconds(50));
+
+        boost::lock_guard<boost::mutex> lk(done_mutex);
+        locked=lock.owns_lock();
+        done=true;
+        done_cond.notify_one();
+    }
+
+    bool is_done() const
+    {
+        return done;
+    }
+
+    typedef test_lock_times_out_if_other_thread_has_lock<Mutex> this_type;
+    
+    void do_test(void (this_type::*test_func)())
+    {
+        Lock lock(m);
+
+        locked=false;
+        done=false;
+        
+        boost::thread t(test_func,this);
+
+        try
+        {
+            {
+                boost::mutex::scoped_lock lk(done_mutex);
+                BOOST_CHECK(done_cond.timed_wait(lk,boost::posix_time::seconds(2),
+                                                 boost::bind(&this_type::is_done,this)));
+                BOOST_CHECK(!locked);
+            }
+            
+            lock.unlock();
+            t.join();
+        }
+        catch(...)
+        {
+            lock.unlock();
+            t.join();
+            throw;
+        }
+    }
+    
+
+    void operator()()
+    {
+        do_test(&this_type::locking_thread);
+        do_test(&this_type::locking_thread_through_constructor);
+    }
+};
+
 template <typename M>
 struct test_timedlock
 {
@@ -181,66 +261,6 @@ struct test_recursive_lock
     }
 };
 
-template<typename Mutex>
-struct test_lock_times_out_if_other_thread_has_lock
-{
-    typedef boost::unique_lock<Mutex> Lock;
-    
-    Mutex m;
-    boost::mutex done_mutex;
-    bool done;
-    bool locked;
-    boost::condition_variable done_cond;
-    
-    test_lock_times_out_if_other_thread_has_lock():
-        done(false),locked(false)
-    {}
-
-    void locking_thread()
-    {
-        Lock lock(m,boost::defer_lock);
-        lock.timed_lock(boost::posix_time::milliseconds(50));
-
-        boost::lock_guard<boost::mutex> lk(done_mutex);
-        locked=lock.owns_lock();
-        done=true;
-        done_cond.notify_one();
-    }
-
-    bool is_done() const
-    {
-        return done;
-    }
-    
-
-    void operator()()
-    {
-        Lock lock(m);
-
-        typedef test_lock_times_out_if_other_thread_has_lock<Mutex> this_type;
-
-        boost::thread t(&this_type::locking_thread,this);
-
-        try
-        {
-            {
-                boost::mutex::scoped_lock lk(done_mutex);
-                BOOST_CHECK(done_cond.timed_wait(lk,boost::posix_time::seconds(2),
-                                                 boost::bind(&this_type::is_done,this)));
-                BOOST_CHECK(!locked);
-            }
-            
-            lock.unlock();
-            t.join();
-        }
-        catch(...)
-        {
-            lock.unlock();
-            t.join();
-            throw;
-        }
-    }
-};
 
 void do_test_mutex()
 {