Use os.geteuid() for checking whether we are root, as suggested by

Michael Hudson.

Lib/test/test_shutil.py

@@ -19,7 +19,7 @@ class TestShutil(unittest.TestCase):
     # See bug #1071513 for why we don't run this on cygwin
     # and bug #1076467 for why we don't run this as root.
     if (hasattr(os, 'chmod') and sys.platform[:6] != 'cygwin'
-        and os.getenv('USER') != 'root'):
+        and not (hasattr(os, 'geteuid') and os.geteuid() == 0)):
         def test_on_error(self):
             self.errorState = 0
             os.mkdir(TESTFN)