tryserver recipe_module: Add get_tags.

tests/git_footers_test.py

 #!/usr/bin/env python
 
 """Tests for git_footers."""
 
 import os
+import mock
+import StringIO
 import sys
 import unittest
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
+from testing_support.auto_stub import TestCase
+
 import git_footers
 
-class GitFootersTest(unittest.TestCase):
+class GitFootersTest(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
@@ skipping 73 matching lines @@
 
     self.assertEqual(
         git_footers.add_footer_change_id('header\n\nBUG: yy\n\nPos: 1', 'Ixxx'),
         'header\n\nBUG: yy\n\nChange-Id: Ixxx\nPos: 1')
 
     # Special case: first line is never a footer, even if it looks line one.
     self.assertEqual(
         git_footers.add_footer_change_id('header: like footer', 'Ixxx'),
         'header: like footer\n\nChange-Id: Ixxx')
 
+  def testReadStdin(self):
+    self.mock(git_footers.sys, 'stdin', StringIO.StringIO(
+        'line\r\notherline\r\n\r\n\r\nFoo: baz'))
+
+    stdout = StringIO.StringIO()
+    self.mock(git_footers.sys, 'stdout', stdout)
+
+    self.assertEqual(git_footers.main([]), 0)
+    self.assertEqual(stdout.getvalue(), "Foo: ['baz']\n")
+
+
 
 if __name__ == '__main__':
   unittest.main()