Added git footers tool to parse conventional metadata from git commits

tests/git_footers_test.py

+#!/usr/bin/env python
+
+"""Tests for git_footers."""
+
+import os
+import sys
+import unittest
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+import git_footers
+
+class GitFootersTest(unittest.TestCase):
+  _message = """
+This is my commit message. There are many like it, but this one is mine.
+
+My commit message is my best friend. It is my life. I must master it.
+
+"""
+
+  _position = 'refs/heads/master@{#292272}'
+
+  _position_footer = 'Cr-Commit-Position: %s\n' % _position
+
+  _git_svn_id = ('svn://svn.chromium.org/chrome/trunk/src@290386'
+                 ' 0039d316-1c4b-4281-b951-d872f2087c98')
+
+  _git_svn_id_footer = 'git-svn-id: %s\n' % _git_svn_id
+
+  _git_svn_id_branch = (
+      'svn://svn.chromium.org/chrome/branches/blabble/src@177288')
+
+  _git_svn_id_footer_branch = 'git-svn-id: %s\n' % _git_svn_id_branch
+
+
+  def testFootersBasic(self):
+    self.assertEqual(
+        git_footers.parse_footers(self._message), {})
+    self.assertEqual(
+        git_footers.parse_footers(self._message + self._position_footer),
+        { 'Cr-Commit-Position': [ self._position ] })
+    self.assertEqual(
+        git_footers.parse_footers(self._message + self._git_svn_id_footer),
+        { 'Git-Svn-Id': [ self._git_svn_id ] })
+    self.assertEqual(
+        git_footers.parse_footers(self._message + self._position_footer
+                                                + self._position_footer),
+        { 'Cr-Commit-Position': [ self._position, self._position ] })
+
+  def testTrunkHeuristic(self):
+    footers = git_footers.parse_footers(self._message + self._git_svn_id_footer)
+    self.assertEqual(
+        footers,
+        { 'Git-Svn-Id': [ self._git_svn_id ] })
+    self.assertEqual(
+        git_footers.get_position(footers),
+        ('refs/heads/master', '290386'))
+
+  def testBranchHeuristic(self):
+    footers = git_footers.parse_footers(self._message +
+                                        self._git_svn_id_footer_branch)
+    self.assertEqual(
+        footers,
+        { 'Git-Svn-Id': [ self._git_svn_id_branch ] })
+    self.assertEqual(
+        git_footers.get_position(footers),
+        ('refs/branch-heads/blabble', None))
+
+if __name__ == '__main__':
+  unittest.main()