diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index b3f72f4..414da98 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -643,6 +643,7 @@
                     self.assertRaises(os.error, os.setreuid, 0, 0)
                 self.assertRaises(OverflowError, os.setreuid, 1<<32, 0)
                 self.assertRaises(OverflowError, os.setreuid, 0, 1<<32)
+                os.setreuid(-1, -1)  # Does nothing, but it needs to accept -1
 
         if hasattr(os, 'setregid'):
             def test_setregid(self):
@@ -650,6 +651,7 @@
                     self.assertRaises(os.error, os.setregid, 0, 0)
                 self.assertRaises(OverflowError, os.setregid, 1<<32, 0)
                 self.assertRaises(OverflowError, os.setregid, 0, 1<<32)
+                os.setregid(-1, -1)  # Does nothing, but it needs to accept -1
 else:
     class PosixUidGidTests(unittest.TestCase):
         pass