text: import pytest
  from importlib import import_module, reload
  from turbulette.conf.exceptions import ImproperlyConfigured
  from turbulette import turbulette_starlette
  
  
  @pytest.mark.usefixtures("reload_resources")
  def test_missing_db_settings(settings):
      settings_module = import_module(settings)
      settings_module.DATABASE_SETTINGS = None
      with pytest.raises(ImproperlyConfigured):
          turbulette_starlette(settings)
      reload(settings_module)
      settings_module.DATABASE_SETTINGS = {"useless_key": "useless"}
      with pytest.raises(ImproperlyConfigured):
          turbulette_starlette(settings)
      reload(settings_module)
      settings_module.DB_DSN = {}
      with pytest.raises(ImproperlyConfigured):
          turbulette_starlette(settings)
      reload(settings_module)
  