Propagate name of system service account to the bot.

appengine/swarming/swarming_bot/bot_code/bot_main_test.py

 #!/usr/bin/env python
 # Copyright 2013 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 import copy
 import json
 import logging
 import os
 import sys
@@ skipping 736 matching lines @@
         self.assertEqual(False, failure)
         self.assertEqual(False, internal_failure)
         self.assertEqual({'os': 'Amiga', 'pool': 'default'}, dimensions)
         self.assertEqual(result, summary)
     self.mock(bot_main, '_call_hook', call_hook)
     result = self._mock_popen(
         url='https://localhost:3',
         expected_auth_params_json={
           'swarming_http_headers': {'A': 'a'},
           'swarming_http_headers_exp': int(time.time() + 3600),
-          'task_service_account': 'bot', # as in task manifest
+          'system_service_account': 'robot@example.com',  # as in task manifest
+          'task_service_account': 'bot',
         })
 
     manifest = {
       'command': ['echo', 'hi'],
       'dimensions': {'os': 'Amiga', 'pool': 'default'},
       'grace_period': 30,
       'hard_timeout': 60,
       'host': 'https://localhost:3',
-      'service_account': 'bot',
+      'service_accounts': {
+        'system': {'service_account': 'robot@example.com'},
+        'task': {'service_account': 'bot'},
+      },
       'task_id': '24',
     }
     self.assertEqual(self.root_dir, self.bot.base_dir)
     bot_main._run_manifest(self.bot, manifest, time.time())
 
   def test_run_manifest_task_failure(self):
     self.mock(bot_main, '_post_error_task', self.print_err_and_fail)
     def call_hook(_botobj, name, *args):
       if name == 'on_after_task':
         failure, internal_failure, dimensions, summary = args
@@ skipping 145 matching lines @@
     self.assertEqual([[bot_main.THIS_FILE, 'start_slave', '--survive']], calls)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   if '-v' in sys.argv:
     TestBotMain.maxDiff = None
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.CRITICAL)
   unittest.main()