code: def test_get_hostname_unset(self, mock_getfqdn):
      assert "first" == net.get_hostname()
  
file_path: airflow/tests/utils/test_net.py
imports: from __future__ import annotations
  import re
  from unittest import mock
  import pytest
  from airflow.exceptions import AirflowConfigException
  from airflow.utils import net
  from tests.test_utils.config import conf_vars
label_desc: Use image node_id 1 for calling the TestGetHostname obj's underlying member method code with example usage: obj.test_get_hostname_unset(mock_getfqdn) without return types