new_contents: import json
  import unittest
  import webtest
  
  from datamodel import Library, Version
  
  from google.appengine.ext import ndb
  
  from test_base import TestBase
  
  class LibraryTests(TestBase):
    def test_versions_for_key(self):
      library_key = ndb.Key(Library, 'a/b')
      Version(id='v2.0.0', sha='x', parent=library_key).put()
      Version(id='v1.0.0', sha='x', parent=library_key).put()
      Version(id='v3.0.0', sha='x', parent=library_key).put()
      Version(id='v3.0.X', sha='x', parent=library_key).put()
      Version(id='xxx', sha='x', parent=library_key).put()
      versions = Library.versions_for_key_async(library_key).get_result()
      self.assertEqual(versions, ['v1.0.0', 'v2.0.0', 'v3.0.0'])
  
  
subject: Add test for versions_for_key_async