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

tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor_unittest.py

 # Copyright 2014 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 json
 import unittest
 
+from telemetry.core import util
 from telemetry.core.platform.power_monitor import monsoon_power_monitor
 
 
 class MonsoonPowerMonitorTest(unittest.TestCase):
   def testEnergyComsumption(self):
     data = {
       'duration_s': 3600.0,
       'samples': [(1.0,1.0), (2.0,2.0), (3.0,3.0), (4.0,4.0)]
     }
     results = monsoon_power_monitor.MonsoonPowerMonitor.ParseSamplingOutput(
         json.dumps(data))
     self.assertEqual(results['power_samples_mw'], [1000, 4000, 9000, 16000])
     self.assertEqual(results['energy_consumption_mwh'], 7500)
+
+  def testPySerialVersionNumber(self):

[tonyg, 2014/06/09 16:13:34]

I think a better test would be to just import monsoon and then check
monsoon.serial.VERSION.

My reasoning is that this test should be testing that the monsoon is working
correctly. Not that Add/InsertDirInPythonPath is working correctly. Tests for
those methods should be in util_unittest.py. And a test there would want to be
generic rather than dependent on pyserial.

+    util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'pyserial')
+    import serial
+    try:
+      import serial.tools
+      import serial.tools.list_ports
+      self.assertTrue(True)
+    except ImportError:
+      self.assertTrue(True)
+
+    util.InsertDirInPythonPath(
+        0, util.GetTelemetryDir(), 'third_party', 'pyserial')
+    import serial
+    self.assertEqual(serial.VERSION, '2.7')
+    try:
+      import serial.tools
+      import serial.tools.list_ports
+      self.assertTrue(True)
+    except ImportError:
+      self.assertTrue(False)