diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 195df26..fb830ae 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -315,11 +315,11 @@
             # This test needs 'id -G'
             return
 
-        # The order of groups isn't important, hence the calls
-        # to sorted.
+        # 'id -G' and 'os.getgroups()' should return the same
+        # groups, ignoring order and duplicates.
         self.assertEqual(
-                list(sorted([int(x) for x in groups.split()])),
-                list(sorted(posix.getgroups())))
+                set([int(x) for x in groups.split()]),
+                set(posix.getgroups()))
 
 class PosixGroupsTester(unittest.TestCase):
     if posix.getuid() == 0 and hasattr(posix, 'getgroups') and sys.platform != 'darwin':