diff --git a/Lib/test/test_epoll.py b/Lib/test/test_epoll.py
index 8ac0f31..10f148f 100644
--- a/Lib/test/test_epoll.py
+++ b/Lib/test/test_epoll.py
@@ -225,7 +225,10 @@
         self.assertFalse(then - now > 0.01)
 
         server.close()
-        ep.unregister(fd)
+
+        with self.assertRaises(OSError) as cm:
+            ep.unregister(fd)
+        self.assertEqual(cm.exception.errno, errno.EBADF)
 
     def test_close(self):
         open_file = open(__file__, "rb")