princ_mappings = []

      for p in options.edit_krb:

          old, new = p.split('=', 1)

      for a in options.add_krb:

          princ_mappings.append({'old': None, 'new': arg_filter(a)})

      for r in options.remove_krb:

          # Finally, assert that things were called as we expected.

          activate_session_mock.assert_called_once_with(session, options)

          session.editUser.assert_called_once_with(user, rename,

                                                    {'new': 'addedkrb', 'old': None},

                                                    {'new': None, 'old': 'removedkrb'}])

          self.assertEqual(rv, None)