code: def test_yaml_expand():
      with open(
          os.path.join(cur_dir, "yaml/test-expand.yml"),
          encoding="utf-8",
      ) as fp:
          a = JAML.load(fp)
      b = expand_dict(a)
      assert b["quote_dict"] == {}
      assert b["quote_string"].startswith("{")
      assert b["quote_string"].endswith("}")
      assert b["nest"]["quote_dict"] == {}
      assert b["nest"]["quote_string"].startswith("{")
      assert b["nest"]["quote_string"].endswith("}")
      assert b["exist_env"] != "$PATH"
      assert b["non_exist_env"] == "$JINA_WHATEVER_ENV"
  
imports: import os
  import pytest
  import yaml
  from jina import Deployment
  from jina.constants import __default_executor__
  from jina.helper import expand_dict, expand_env_var
  from jina.jaml import JAML
  from jina.serve.executors import BaseExecutor
  from jina.serve.runtimes.gateway.gateway import BaseGateway
  from jina.serve.runtimes.gateway.http import HTTPGateway
label_desc: Use image node_id 2 for calling a global function with example usage: test_yaml_expand() without return types