diff -r 19c4528f53b0 Lib/test/test_threading.py
--- a/Lib/test/test_threading.py	Wed Feb 01 04:42:48 2017 +0300
+++ b/Lib/test/test_threading.py	Fri Feb 03 22:51:00 2017 +0800
@@ -170,6 +170,9 @@
         mutex.acquire()
         self.assertIn(tid, threading._active)
         self.assertIsInstance(threading._active[tid], threading._DummyThread)
+        #Issue 29376
+        self.assertTrue(threading._active[tid].is_alive())
+        self.assertRegex(repr(threading._active[tid]), '_DummyThread')
         del threading._active[tid]
 
     # PyThreadState_SetAsyncExc() is a CPython-only gimmick, not (currently)
diff -r 19c4528f53b0 Lib/threading.py
--- a/Lib/threading.py	Wed Feb 01 04:42:48 2017 +0300
+++ b/Lib/threading.py	Fri Feb 03 22:51:00 2017 +0800
@@ -1217,6 +1217,10 @@
     def _stop(self):
         pass
 
+    def is_alive(self):
+        assert not self._is_stopped and self._started.is_set()
+        return True
+
     def join(self, timeout=None):
         assert False, "cannot join a dummy thread"