diff --git a/Lib/test/test_grp.py b/Lib/test/test_grp.py
index b4701d5..e9e1758 100644
--- a/Lib/test/test_grp.py
+++ b/Lib/test/test_grp.py
@@ -33,12 +33,16 @@
             e2 = grp.getgrgid(e.gr_gid)
             self.check_value(e2)
             self.assertEqual(e2.gr_gid, e.gr_gid)
-            e2 = grp.getgrnam(e.gr_name)
+            name = e.gr_name
+            if name.startswith('+') or name.startswith('-'):
+                # NIS-related entry
+                continue
+            e2 = grp.getgrnam(name)
             self.check_value(e2)
             # There are instances where getgrall() returns group names in
             # lowercase while getgrgid() returns proper casing.
             # Discovered on Ubuntu 5.04 (custom).
-            self.assertEqual(e2.gr_name.lower(), e.gr_name.lower())
+            self.assertEqual(e2.gr_name.lower(), name.lower())
 
     def test_errors(self):
         self.assertRaises(TypeError, grp.getgrgid)