code: def test_as_teardown(dag_maker, setup_type, work_type, teardown_type):
      """
      Check that as_teardown works properly as implemented in PlainXComArg
  
      It should mark the teardown as teardown, and if a task is provided, it should mark that as setup
      and set it as a direct upstream.
      """
      with dag_maker() as dag:
          s1 = make_task(name="s1", type_=setup_type)
          w1 = make_task(name="w1", type_=work_type)
          t1 = make_task(name="t1", type_=teardown_type)
      # initial conditions
      assert cleared_tasks(dag, "w1") == {"w1"}
  
      # after setting deps, still none are setup / teardown
      # verify relationships
      s1 >> w1 >> t1
      assert cleared_tasks(dag, "w1") == {"w1", "t1"}
      assert get_task_attr(t1, "is_teardown") is False
      assert get_task_attr(s1, "is_setup") is False
      assert get_task_attr(t1, "upstream_task_ids") == {"w1"}
  
      # now when we use as_teardown, s1 should be setup, t1 should be teardown, and we should have s1 >> t1
      t1.as_teardown(setups=s1)
      assert cleared_tasks(dag, "w1") == {"s1", "w1", "t1"}
      assert get_task_attr(t1, "is_teardown") is True
      assert get_task_attr(s1, "is_setup") is True
      assert get_task_attr(t1, "upstream_task_ids") == {"w1", "s1"}
  
file_path: airflow/tests/models/test_taskmixin.py
imports: from __future__ import annotations
  import itertools
  import pytest
  from airflow.decorators import setup, task, teardown
  from airflow.models.baseoperator import BaseOperator
label_desc: Use image node_id 4 for calling a global function with example usage: test_as_teardown(dag_maker, setup_type, work_type, teardown_type) without return types