Cross-repo recipe package system.

third_party/recipe_engine/expect_tests/main.py

 # 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.
 
 import argparse
 import multiprocessing
 import sys
 
 from .cover import CoverageContext
 
@@ skipping 33 matching lines @@
         handler=handle_list.ListHandler,
         test_glob=[prefix],
         jobs=1,
     )
     ctx = CoverageContext('', [], False, False)
     result_loop(self._gen, ctx.create_subprocess_context(), options)
     return handle_list.ListHandler.COMPLETION_LIST
 
 
 def _parse_args(args, test_gen):
-  args = args or sys.argv[1:]
+  if args is None:
+    args = sys.argv[1:]
 
   # Set the default mode if not specified and not passing --help
   search_names = set(HANDLERS.keys() + ['-h', '--help'])
   if not any(arg in search_names for arg in args):
     args.insert(0, 'test')
 
   parser = argparse.ArgumentParser()
   subparsers = parser.add_subparsers(
       title='Mode (default "test")', dest='mode',
       help='See `[mode] --help` for more options.')
@@ skipping 89 matching lines @@
         test_gen, cover_ctx.create_subprocess_context(), opts)
 
     cover_ctx.cleanup()
     if not killed and not opts.test_glob:
       if not cover_ctx.report(verbose=opts.verbose, omit=cover_omit):
         sys.exit(2)
 
     sys.exit(error or killed)
   except KeyboardInterrupt:
     pass