Revert of [autoroller] All commits in updates(), only roll interesting ones.

unittests/repo_test_util.py

 # Copyright 2016 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.
 
 """Utilities for testing with real repos (e.g. git)."""
 
 
 import contextlib
 import logging
 import os
@@ skipping 105 matching lines @@
           '#### PER-REPO CONFIGURATION (editable) ####',
           'REPO_ROOT = "."',
           'RECIPES_CFG = os.path.join("infra", "config", "recipes.cfg")',
           '#### END PER-REPO CONFIGURATION ####',
           'if sys.argv[1] != "fetch":',
           '  sys.exit(subprocess.call(',
           '      [sys.executable, %r, "--package", %r] + sys.argv[1:]))' % (
             self._recipe_tool,
             os.path.join(repo_dir, 'infra', 'config', 'recipes.cfg')),
         ]))
-      with open('some_file', 'w') as f:
-        print >> f, 'I\'m a file'
-      subprocess.check_output(['git', 'add', 'recipes.py', 'some_file'])
+      subprocess.check_output(['git', 'add', 'recipes.py'])
     rev = self.update_recipes_cfg(name, spec)
     return {
         'name': name,
         'root': repo_dir,
         'revision': rev,
         'spec': spec,
     }
 
   def repo_setup(self, repo_deps):
     """Creates a set of repos with recipes.cfg reflecting requested
@@ skipping 51 matching lines @@
 
   def commit_in_repo(self, repo, message='Empty commit',
                      author_name='John Doe',
                      author_email='john.doe@example.com'):
     """Creates a commit in given repo."""
     root = repo['root']
 
     env = dict(os.environ)
     env['GIT_AUTHOR_NAME'] = author_name
     env['GIT_AUTHOR_EMAIL'] = author_email
-    with open(os.path.join(root, 'some_file'), 'a') as f:
-      print >> f, message
     subprocess.check_output(
       ['git', '-C', root, 'commit',
-       '-a', '-m', message], env=env)
+       '-a', '--allow-empty',
+       '-m', message], env=env)
     rev = subprocess.check_output(
       ['git', '-C', root, 'rev-parse', 'HEAD']).strip()
     return {
         'root': repo['root'],
         'revision': rev,
         'spec': repo['spec'],
         'author_name': author_name,
         'author_email': author_email,
         'message_lines': message.splitlines(),
     }
@@ skipping 127 matching lines @@
         os.unlink(os.path.join(module_dir, 'example.py'))
 
       self.train_recipes(repo)
 
       subprocess.check_call(['git', 'add', module_dir])
       message = ' '.join(
         ['update %r recipe_module: ' % name] +
         ['%s(%s)' % t for t in methods.iteritems()]
       )
       return self.commit_in_repo(repo, message)