code: def test_local_clusters():
      """
      This tests the various behaviors of connecting to local clusters:
  
      * Using `ray.client("local").connect() ` should always create a new
        cluster.
      * Using `ray.cleint().connectIO` should create a new cluster if it doesn't
        connect to an existing one.
      * Using `ray.client().connect()` should only connect to a cluster if it
        was created with `ray start --head`, not from a python program.
  
      It does tests if two calls are in the same cluster by trying to create an
      actor with the same name in the same namespace, which will error and cause
      the script have a non-zero exit, which throws an exception.
      """
      driver_template = """
  import ray
  info = ray.client({address}).namespace("").connect()
  
  @ray.remote
  class Foo:
      def ping(self):
          return "pong"
  
  a = Foo.options(name="abc", lifetime="detached").remote()
  ray.get(a.ping.remote())
  
  import time
  while True:
      time.sleep(30)
  
  """
      blocking_local_script = driver_template.format(
          address="'local'", blocking=True
      )
      blocking_noaddr_script = driver_template.format(
          address="", blocking=True
      )
  
      # This should start a cluster.
      p1 = run_string_as_driver_nonblocking(blocking_local_script)
      # ray.client("local").connect() should start a second cluster.
      p2 = run_string_as_driver_nonblocking(blocking_local_script)
      # ray.client().connect() shouldn't connect to a cluster started by
      # ray.client("local").connect() so it should create a third one.
      p3 = run_string_as_driver_nonblocking(blocking_noaddr_script)
      # ray.client().connect() shouldn't connect to a cluster started by
      # ray.client().connect() so it should create a fourth one.
      p4 = run_string_as_driver_nonblocking(blocking_noaddr_script)
  
      wait_for_condition(
          lambda: len(ray._private.services.find_gcs_addresses()) == 4,
          retry_interval_ms=1000,
      )
  
      p1.kill()
      p2.kill()
      p3.kill()
      p4.kill()
      # Prevent flakiness since fatesharing takes some time.
      subprocess.check_output("ray stop --force", shell=True)
  
      # Since there's a cluster started with `ray start --head`
      # we should connect to it instead.
      subprocess.check_output("ray start --head", shell=True)
      # The assertion in the driver should cause the script to fail if we start
      # a new cluster instead of connecting.
      run_string_as_driver(
          """
  import ray
  ray.client().connect()
  assert len(ray._private.services.find_gcs_addresses()) == 1
      """
      )
      # ray.client("local").connect() should always create a new cluster even if
      # there's one running.
      p1 = run_string_as_driver_nonblocking(blocking_local_script)
      wait_for_condition(
          lambda: len(ray._private.services.find_gcs_addresses()) == 2,
          retry_interval_ms=1000,
      )
      p1.kill()
      subprocess.check_output("ray stop --force", shell=True)
  
imports: import os
  import subprocess
  import sys
  import warnings
  from unittest.mock import Mock, patch
  import pytest
  import ray
  import ray.client_builder
  import ray.util.client.server.server
  from ray._private.test_utils import run_string_as_driver, run_string_as_driver_nonblocking, wait_for_condition, skip_flaky_core_test_premerge
  from ray.util.state import list_workers
label_desc: Use image node_id 5 for calling a global function with example usage: test_local_clusters() without return types