power_LoadTest: Add parameter for custom tasks

client/site_tests/hardware_Backlight/hardware_Backlight.py

 # Copyright (c) 2010 The Chromium OS 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 utils
 from autotest_lib.client.bin import test
 from autotest_lib.client.common_lib import error
 
 def backlight_tool(args):
     cmd = 'backlight-tool %s' % args
     return utils.system_output(cmd)
 
 class hardware_Backlight(test.test):
     version = 1
 
     def run_once(self):
         try:
             brightness = int(backlight_tool("--get_brightness").rstrip())
         except error.CmdError, e:
             raise error.TestFail('Cannot get brightness with backlight-tool')
         max_brightness = int(backlight_tool("--get_max_brightness").rstrip())
+        logging.debug("max_brightness = %d" % max_brightness)
         try:
             for i in range(max_brightness + 1):
                 backlight_tool("--set_brightness %d" % i)
                 result = int(backlight_tool("--get_brightness").rstrip())
+                logging.debug("result = %d" % result)
                 if i != result:
                     raise error.TestFail('Adjusting backlight should change ' \
                                          'actual brightness')
         finally:
             backlight_tool("--set_brightness %d" % brightness)