[test_runner] support relative paths on argument --shared-prefs-file

build/android/test_runner.py

 #!/usr/bin/env python
 #
 # Copyright 2013 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.
 
 """Runs all types of tests from one unified interface."""
 
 import argparse
 import collections
@@ skipping 402 matching lines @@
   parser.add_argument(
       '--runtime-deps-path',
       dest='runtime_deps_path', type=os.path.realpath,
       help='Runtime data dependency file from GN.')
   parser.add_argument(
       '--screenshot-directory',
       dest='screenshot_dir', type=os.path.realpath,
       help='Capture screenshots of test failures')
   parser.add_argument(
       '--shared-prefs-file',
-      dest='shared_prefs_file', type=os.path.realpath,
+      dest='shared_prefs_file', type=os.path.abspath,

[shenghuazhang, 2017/07/25 20:44:45]

Type realpath changes value "//home/..." to "/home/...", so set it to abspath
here, and handle the realpath below.

[jbudorick, 2017/07/25 21:07:46]

I think you're on the right track here, but you can do this more concisely by
taking advantage of the fact that what we pass to type doesn't have to be an
actual type -- it can be a function (as abspath and realpath are). If you write
a function that takes a string, does the same manipulation you've got in the if
block below, and then returns the result, you should be able to use that here
and reuse it later for other path arguments.

[shenghuazhang, 2017/07/25 21:28:10]

Thanks for this suggestion! This should be much more clean and reusable.

       help='The relative path to a file containing JSON list of shared '
            'preference files to edit and how to do so. Example list: '
            '[{'
            '  "package": "com.package.example",'
            '  "filename": "ExampleSettings.xml",'
            '  "set": {'
            '    "boolean_key_in_xml": true,'
            '    "string_key_in_xml": "string_value"'
            '  },'
            '  "remove": ['
@@ skipping 526 matching lines @@
       parser.error('unrecognized arguments: %s' % ' '.join(unknown_args))
 
   # --replace-system-package has the potential to cause issues if
   # --enable-concurrent-adb is set, so disallow that combination
   if (hasattr(args, 'replace_system_package') and
       hasattr(args, 'enable_concurrent_adb') and args.replace_system_package and
       args.enable_concurrent_adb):
     parser.error('--replace-system-package and --enable-concurrent-adb cannot '
                  'be used together')
 
+  if hasattr(args, 'shared_prefs_file') and args.shared_prefs_file:
+    if args.shared_prefs_file.startswith('//'):
+      args.shared_prefs_file = os.path.abspath(
+          os.path.join(host_paths.DIR_SOURCE_ROOT,
+                       args.shared_prefs_file[2:].replace('/', os.sep)))
+    args.shared_prefs_file = os.path.realpath(args.shared_prefs_file)
+
   try:
     return RunTestsCommand(args)
   except base_error.BaseError as e:
     logging.exception('Error occurred.')
     if e.is_infra_error:
       return constants.INFRA_EXIT_CODE
     return constants.ERROR_EXIT_CODE
   except: # pylint: disable=W0702
     logging.exception('Unrecognized error occurred.')
     return constants.ERROR_EXIT_CODE
 
 
 if __name__ == '__main__':
   sys.exit(main())