'The persistence service will detect if an existing configuration
saved in a file is a previous version and perform a migration to
the latest version.'

def test_old_configuration_is_upgraded(self):

    path = FilePath(self.mktemp())
    path.makedirs()
    v1_config_file = path.child('current_configuration.v1.json')
    v1_config_file.setContent(V1_TEST_DEPLOYMENT_JSON)
    config_path = path.child('current_configuration.json')
    self.service(path)
    configuration = wire_decode(config_path.getContent())
    self.assertEqual(configuration.version, _CONFIG_VERSION)
