code: def test_local(self):
      @ray.remote
      class TestRay:
          def hostname(self):
              import socket
  
              return socket.gethostname()
  
      sc = init_spark_on_local(cores=8)
      config = {
          "object_spilling_config": '{"type":"filesystem",'
          '"params":{"directory_path":"/tmp/spill"}}'
      }
      ray_ctx = OrcaRayContext(
          sc=sc,
          object_store_memory="1g",
          ray_node_cpu_cores=4,
          system_config=config,
      )
      address_info = ray_ctx.init()
      assert "object_store_address" in address_info
      actors = [TestRay.remote() for i in range(0, 4)]
      print(ray.get([actor.hostname.remote() for actor in actors]))
      ray_ctx.stop()
      sc.stop()
  
imports: from unittest import TestCase
  import pytest
  import ray
  from bigdl.dllib.nncontext import init_spark_on_local
  from bigdl.orca.ray import OrcaRayContext
label_desc: Use image node_id 1 for calling the TestRayLocal obj's underlying member method code with example usage: obj.test_local() and returns: socket