Tests try to write to /tmp (sandbox).
http://code.google.com/p/python-gflags/issues/detail?id=13

From 4a430830e75bfe2228e9d953b12f74a20ec2cb8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= <mgorny@gentoo.org>
Date: Sun, 16 Dec 2012 16:53:24 +0100
Subject: [PATCH] Use tempfile.mkdtemp() to create temporary directory.

This creates an unique directory, and respects TMPDIR.
---
 tests/gflags_unittest.py | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tests/gflags_unittest.py b/tests/gflags_unittest.py
index 8e948bf..fcddb7b 100755
--- a/tests/gflags_unittest.py
+++ b/tests/gflags_unittest.py
@@ -38,6 +38,7 @@ import cStringIO
 import sys
 import os
 import shutil
+import tempfile
 
 import gflags
 from flags_modules_for_testing import module_foo
@@ -907,17 +908,16 @@ class LoadFromFlagFileTest(googletest.TestCase):
                       flag_values=self.flag_values)
     self.files_to_delete = []
 
+    # Figure out where to create temporary files
+    self.tmp_path = tempfile.mkdtemp(prefix='gflags_unittest')
+
   def tearDown(self):
     self._RemoveTestFiles()
 
   def _SetupTestFiles(self):
     """ Creates and sets up some dummy flagfile files with bogus flags"""
 
-    # Figure out where to create temporary files
-    tmp_path = '/tmp/flags_unittest'
-    if os.path.exists(tmp_path):
-      shutil.rmtree(tmp_path)
-    os.makedirs(tmp_path)
+    tmp_path = self.tmp_path
 
     try:
       tmp_flag_file_1 = open(tmp_path + '/UnitTestFile1.tst', 'w')
@@ -973,6 +973,7 @@ class LoadFromFlagFileTest(googletest.TestCase):
         os.remove(file_name)
       except OSError, e_msg:
         print '%s\n, Problem deleting test file' % e_msg
+    shutil.rmtree(self.tmp_path)
   #end RemoveTestFiles def
 
   def _ReadFlagsFromFiles(self, argv, force_gnu):
-- 
1.8.0.2