code: def _init_modules_stub(self, **_):
          
          from google.appengine.api import request_info
          # edit all_versions per modules & versions thereof needing tests
          all_versions = {}  # {'default': [1], 'andsome': [2], 'others': [1]}
          def_versions = {}  # {m: all_versions[m][0] for m in all_versions}
          m2h = {}  # {m: {def_versions[m]: 'localhost:8080'} for m in def_versions}
          for module in self.configuration.modules:
              module_name = module._module_name or 'default'
              module_version = module._version or '1'
              all_versions[module_name] = [module_version]
              def_versions[module_name] = module_version
              m2h[module_name] = {module_version: 'localhost:8080'}
  
          request_info._local_dispatcher = request_info._LocalFakeDispatcher(
              module_names=list(all_versions),
              module_name_to_versions=all_versions,
              module_name_to_default_versions=def_versions,
              module_name_to_version_to_hostname=m2h)
          self.testbed.init_modules_stub()
docs: Initializes the modules stub based off of your current yaml files
  
          Implements solution from
          http://stackoverflow.com/questions/28166558/invalidmoduleerror-when-using-testbed-to-unit-test-google-app-engine