os.popen().close() returns None on success, not 0...
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 5ed2a0f..21473fc 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -630,7 +630,7 @@
             groups = idg.read().strip()
             ret = idg.close()
 
-        if ret != 0 or not groups:
+        if ret != None or not groups:
             raise unittest.SkipTest("need working 'id -G'")
 
         self.assertEqual(
@@ -644,7 +644,7 @@
             groups = idg.read().strip()
             ret = idg.close()
 
-        if ret != 0 or not groups:
+        if ret != None or not groups:
             raise unittest.SkipTest("need working 'id -G'")
 
         # 'id -G' and 'os.getgroups()' should return the same