code: def test_discovery() -> None:
      # Tests that this plugin can be discovered via the plugins subsystem when looking for Launchers
      assert RayLauncher.__name__ in [
          x.__name__ for x in Plugins.instance().discover(Launcher)
      ]
  
file_path: hydra/plugins/hydra_ray_launcher/tests/test_ray_launcher.py
imports: import sys
  from hydra.core.plugins import Plugins
  from hydra.plugins.launcher import Launcher
  from hydra.test_utils.launcher_common_tests import IntegrationTestSuite, LauncherTestSuite
  from hydra.test_utils.test_utils import chdir_plugin_root
  from pytest import mark
  from hydra_plugins.hydra_ray_launcher.ray_launcher import RayLauncher
label_desc: Use image node_id 1 for calling a global function with example usage: test_discovery() without return types