def METHOD_NAME(self):
    # test that per_dataset_config config load the default config, then the specialized config
    with tempfile.TemporaryDirectory() as tempdir:
        configfile = os.path.join(tempdir, "config.yaml")
        with open(configfile, "w") as fconfig:
            config = """
            server:
                multi_dataset:
                    dataroots:
                        test:
                            base_url: test
                            dataroot: fake_dataroot
            """
            fconfig.write(config)
        app_config = AppConfig(configfile)
        # test config from specialization
        self.assertEqual(app_config.server__multi_dataset__dataroots["test"]["base_url"], "test")