code: def test_init(self):
      node_num = 4
      address_info = self.ray_ctx.init()
      assert (
          OrcaRayContext._active_ray_context
      ), "OrcaRayContext has not been initialized"
      assert "object_store_address" in address_info
      actors = [TestRay.remote() for i in range(0, node_num)]
      print(ray.get([actor.hostname.remote() for actor in actors]))
  
file_path: BigDL/python/orca/test/bigdl/orca/ray/ray_cluster/test_rayctx_local.py
imports: from unittest import TestCase
  import pytest
  import ray
  from bigdl.orca import stop_orca_context
  from bigdl.orca.ray import OrcaRayContext
label_desc: Use image node_id 3 for calling the TestUtil obj's underlying member method code with example usage: obj.test_init() without return types