Python 3 compatibility

pylib/gyp/generator/msvs_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """ Unit tests for the msvs.py file. """
 
 import gyp.generator.msvs as msvs
 import unittest
-import StringIO
+try:
+  from StringIO import StringIO
+except ImportError:
+  from io import StringIO
 
 
 class TestSequenceFunctions(unittest.TestCase):
 
   def setUp(self):
-    self.stderr = StringIO.StringIO()
+    self.stderr = StringIO()
 
   def test_GetLibraries(self):
     self.assertEqual(
       msvs._GetLibraries({}),
       [])
     self.assertEqual(
       msvs._GetLibraries({'libraries': []}),
       [])
     self.assertEqual(
       msvs._GetLibraries({'other':'foo', 'libraries': ['a.lib']}),
       ['a.lib'])
     self.assertEqual(
       msvs._GetLibraries({'libraries': ['-la']}),
       ['a.lib'])
     self.assertEqual(
       msvs._GetLibraries({'libraries': ['a.lib', 'b.lib', 'c.lib', '-lb.lib',
                                    '-lb.lib', 'd.lib', 'a.lib']}),
       ['c.lib', 'b.lib', 'd.lib', 'a.lib'])
 
 if __name__ == '__main__':
   unittest.main()