code: def test_should_return_correct_path_name(self):
      from airflow import plugins_manager
  
      source = plugins_manager.PluginsDirectorySource(__file__)
      assert "test_plugins_manager.py" == source.path
      assert "$PLUGINS_FOLDER/test_plugins_manager.py" == str(source)
      assert (
          "<em>$PLUGINS_FOLDER/</em>test_plugins_manager.py"
          == source.__html__()
      )
  
imports: from __future__ import annotations
  import importlib
  import inspect
  import logging
  import os
  import sys
  from pathlib import Path
  from unittest import mock
  import pytest
  from airflow.hooks.base import BaseHook
  from airflow.listeners.listener import get_listener_manager
  from airflow.plugins_manager import AirflowPlugin
  from airflow.utils.module_loading import qualname
  from airflow.www import app
  from tests.test_utils.config import conf_vars
  from tests.test_utils.mock_plugins import mock_plugin_manager
label_desc: Use image node_id 1 for calling the TestPluginsDirectorySource obj's underlying member method code with example usage: obj.test_should_return_correct_path_name() without return types