diff -r 4de4b5a4e405 Lib/test/test_selectors.py
--- a/Lib/test/test_selectors.py	Sun Dec 08 10:58:28 2013 -0800
+++ b/Lib/test/test_selectors.py	Sun Dec 08 13:18:49 2013 -0800
@@ -109,7 +109,6 @@
         s.unregister(r)
         s.unregister(w)
 
-    @unittest.skipUnless(os.name == 'posix', "requires posix")
     def test_unregister_after_fd_close_and_reuse(self):
         s = self.SELECTOR()
         self.addCleanup(s.close)
@@ -117,11 +116,12 @@
         r, w = rd.fileno(), wr.fileno()
         s.register(r, selectors.EVENT_READ)
         s.register(w, selectors.EVENT_WRITE)
-        rd2, wr2 = self.make_socketpair()
         rd.close()
         wr.close()
-        os.dup2(rd2.fileno(), r)
-        os.dup2(wr2.fileno(), w)
+        rd2, wr2 = self.make_socketpair()
+        # The test expects that the new socketpair reuses the same FDs.
+        assert rd2.fileno() == r
+        assert wr2.fileno() == w
         self.addCleanup(os.close, r)
         self.addCleanup(os.close, w)
         s.unregister(r)