[PowerProfiler] Make sure correct version of pySerial is imported with monsoon profiler.

tools/telemetry/telemetry/core/util_unittest.py

 # Copyright 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 import os
 import unittest
 import shutil
 import tempfile
 
 from telemetry.core import util
 
@@ skipping 44 matching lines @@
       with open(
           os.path.join(self.test_directory, 'test_%03d.json' % i), 'w') as _:
         pass
     next_json_test_file_path = util.GetSequentialFileName(
         os.path.join(self.test_directory, 'test'))
     self.assertEquals(os.path.join(self.test_directory, 'test_003'),
                       next_json_test_file_path)
 
   def tearDown(self):
     shutil.rmtree(self.test_directory)
+
+class PySerialVersionTest(unittest.TestCase):

[qsr, 2014/06/11 12:24:21]

Don't you need to call AddDirToPythonPath? Is it only working because something
else has been doing this before you?

[vivekg, 2014/06/11 12:41:41]

Yes you are right. We should call AddDirToPythonPath for the completeness of the
test. I will change it.

The reason its working is because of telemetry/core/platform/profiler/monsoon.py
is calling this function at the import statement. 

[qsr, 2014/06/11 13:23:38]

 If your test was not failing, it is probably not the right one. Moreover, it
will break when we update pyserial for no good reason.

 What about creating 2 directories with 2 stupid module with the same name and a
variable with 2 different values, and checking that the order of import matters.

+  def testPySerialVersion(self):
+    import serial
+    self.assertEqual(serial.VERSION, '2.7')