[BattOr] Add real device smoke test

common/battor/battor/battor_wrapper.py

Index: common/battor/battor/battor_wrapper.py
diff --git a/common/battor/battor/battor_wrapper.py b/common/battor/battor/battor_wrapper.py
index e2966eb3c54e52e0232890b8d93dc03255580f7a..483dc9ee1d6dcea197c5fb8bc8d8cfd00b6688b3 100644
--- a/common/battor/battor/battor_wrapper.py
+++ b/common/battor/battor/battor_wrapper.py
@@ -14,6 +14,11 @@ import dependency_manager
 from devil.utils import battor_device_mapping
 from devil.utils import find_usb_devices
 
+sys.path.insert(

[charliea (OOO until 10-5), 2016/04/29 15:11:07]

I think that this should be added here:

https://cs.corp.google.com/github/catapult-project/catapult/telemetry/telemet...

That way, you can just say 'import serial'

[rnephew (Reviews Here), 2016/04/29 17:05:57]

Will that work, this being part of common? Or do you mean add it to __init__.py
in common/battor/battor?

Adding there as I assume thats what was intended. 

[charliea (OOO until 10-5), 2016/04/29 17:18:17]

Uhhh... sure, let's pretend like I was smart enough to suggest that :)

+    1, os.path.join(os.path.dirname(__file__), '..', '..', '..', 'telemetry',
+                    'third_party', 'pyserial'))
+import serial
+from serial.tools import list_ports
 
 class BattorWrapper(object):
   """A class for communicating with a BattOr in python."""
@@ -128,9 +133,11 @@ class BattorWrapper(object):
       raise battor_error.BattorError(
           '%s is an unsupported platform.' % target_platform)
     if target_platform in ['win']:
-      # TODO: We need a way to automatically detect correct port.
-      # crbug.com/60397
-      return 'COM3'
+      for (port, desc, _) in serial.tools.list_ports.comports():
+        if 'USB Serial Port' in desc:

[charliea (OOO until 10-5), 2016/04/29 15:11:07]

Can you add a comment describing why this is necessary? Something like:

Right now, the BattOr agent binary isn't able to automatically detect the BattOr
port on Windows. To get around this, we know that the BattOr shows up with a
name of 'USB Serial Port', so use the COM port that corresponds to a device with
that name.

[rnephew (Reviews Here), 2016/04/29 17:05:57]

Done.

+          return port
+      raise battor_error.BattorError(
+          'Could not find BattOr attached to machine.')
     device_tree = find_usb_devices.GetBusNumberToDeviceTreeMap(fast=True)
     if battor_path:
       if not isinstance(battor_path, basestring):