Move the parser creation code in its own function to enable unit testing.

Unit test follow in next CL.

R=dpranke@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/7766005

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@98480 0039d316-1c4b-4281-b951-d872f2087c98

gclient.py

@@ -1229,24 +1229,8 @@ def GenUsage(parser, command):
   parser.epilog = getattr(obj, 'epilog', None)
 
 
-def Main(argv):
-  """Doesn't parse the arguments here, just find the right subcommand to
-  execute."""
-  if sys.hexversion < 0x02050000:
-    print >> sys.stderr, (
-        '\nYour python version is unsupported, please upgrade.\n')
-  try:
-    # Make stdout auto-flush so buildbot doesn't kill us during lengthy
-    # operations. Python as a strong tendency to buffer sys.stdout.
-    sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
-    # Make stdout annotated with the thread ids.
-    sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout)
-    # Do it late so all commands are listed.
-    # Unused variable 'usage'
-    # pylint: disable=W0612
-    CMDhelp.usage = ('\n\nCommands are:\n' + '\n'.join([
-        '  %-10s %s' % (fn[3:], Command(fn[3:]).__doc__.split('\n')[0].strip())
-        for fn in dir(sys.modules[__name__]) if fn.startswith('CMD')]))
+def Parser():
+  """Returns the default parser."""
   parser = optparse.OptionParser(version='%prog ' + __version__)
   parser.add_option('-j', '--jobs', default=1, type='int',
                     help='Specify how many SCM commands can run in parallel; '
@@ -1290,6 +1274,28 @@ def Main(argv):
   parser.parse_args = Parse
   # We don't want wordwrapping in epilog (usually examples)
   parser.format_epilog = lambda _: parser.epilog or ''
+  return parser
+
+
+def Main(argv):
+  """Doesn't parse the arguments here, just find the right subcommand to
+  execute."""
+  if sys.hexversion < 0x02050000:
+    print >> sys.stderr, (
+        '\nYour python version is unsupported, please upgrade.\n')
+  try:
+    # Make stdout auto-flush so buildbot doesn't kill us during lengthy
+    # operations. Python as a strong tendency to buffer sys.stdout.
+    sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
+    # Make stdout annotated with the thread ids.
+    sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout)
+    # Do it late so all commands are listed.
+    # Unused variable 'usage'
+    # pylint: disable=W0612
+    CMDhelp.usage = ('\n\nCommands are:\n' + '\n'.join([
+        '  %-10s %s' % (fn[3:], Command(fn[3:]).__doc__.split('\n')[0].strip())
+        for fn in dir(sys.modules[__name__]) if fn.startswith('CMD')]))
+    parser = Parser()
     if argv:
       command = Command(argv[0])
       if command: