Issue #18174: Fix fd leaks in tests.
diff --git a/Lib/test/test_openpty.py b/Lib/test/test_openpty.py
index 20c4fe2..4b34b3a 100644
--- a/Lib/test/test_openpty.py
+++ b/Lib/test/test_openpty.py
@@ -10,6 +10,8 @@
 class OpenptyTest(unittest.TestCase):
     def test(self):
         master, slave = os.openpty()
+        self.addCleanup(os.close, master)
+        self.addCleanup(os.close, slave)
         if not os.isatty(slave):
             self.fail("Slave-end of pty is not a terminal.")