Add new method to disable android device charging.

build/android/pylib/device/device_utils_test.py

 #!/usr/bin/env python
 # 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.
 
 """
 Unit tests for the contents of device_utils.py (mostly DeviceUtils).
 """
 
 # pylint: disable=C0321
@@ skipping 1450 matching lines @@
   def testSetCharging_disabled(self):
     with self.assertCalls(
         (self.call.device.FileExists(mock.ANY), True),
         (self.call.device.RunShellCommand(mock.ANY, check_return=True), []),
         (self.call.device.GetCharging(), True),
         (self.call.device.RunShellCommand(mock.ANY, check_return=True), []),
         (self.call.device.GetCharging(), False)):
       self.device.SetCharging(False)
 
 
+class DeviceUtilsSetBatteryMeasurementTest(DeviceUtilsTest):
+
+  def testBatteryMeasurement(self):
+    with self.assertCalls(
+        (self.call.device.RunShellCommand(
+            mock.ANY, retries=0, single_line=True,

[perezju, 2015/03/13 10:19:07]

I'm never quite sure what is the "right" level of abstraction for these tests;
but maybe we could change some of these mock.ANY's to the actual commands?

[rnephew (Wrong account), 2015/03/16 16:33:40]

Done.

+            timeout=10, check_return=True), '22'),
+        (self.call.device.RunShellCommand(mock.ANY, check_return=True), []),
+        (self.call.device.RunShellCommand(mock.ANY, check_return=True), []),
+        (self.call.device.RunShellCommand(mock.ANY, check_return=True), []),
+        (self.call.device.GetCharging(), False),
+        (self.call.device.RunShellCommand(mock.ANY, check_return=True), []),
+        (self.call.device.GetCharging(), True)):
+      with self.device.BatteryMeasurement():
+        pass
+
 
 class DeviceUtilsStrTest(DeviceUtilsTest):
 
   def testStr_returnsSerial(self):
     with self.assertCalls(
         (self.call.adb.GetDeviceSerial(), '0123456789abcdef')):
       self.assertEqual('0123456789abcdef', str(self.device))
 
 
 class DeviceUtilsParallelTest(mock_calls.TestCase):
@@ skipping 14 matching lines @@
     with self.assertCall(
         mock.call.pylib.device.adb_wrapper.AdbWrapper.GetDevices(), []):
       with self.assertRaises(device_errors.NoDevicesError):
         device_utils.DeviceUtils.parallel()
 
 
 if __name__ == '__main__':
   logging.getLogger().setLevel(logging.DEBUG)
   unittest.main(verbosity=2)