code: def test_jsonsink_input():
      ds = nio.JSONFileSink()
      assert ds.inputs._outputs == {}
  
      ds = nio.JSONFileSink(in_dict={"foo": "var"})
      assert ds.inputs.in_dict == {"foo": "var"}
  
      ds = nio.JSONFileSink(infields=["test"])
      assert "test" in ds.inputs.copyable_trait_names()
  
imports: import os
  import copy
  import simplejson
  import glob
  import os.path
  from subprocess import Popen
  import hashlib
  from collections import namedtuple
  import pytest
  import nipype
  import nipype.interfaces.io
  from nipype.interfaces.base.traits_extension import isdefined
  from nipype.interfaces.base import Undefined, TraitError
  from nipype.utils.filemanip import dist_is_editable
  from subprocess import check_call, CalledProcessError
label_desc: Use image node_id 20 for calling a global function with example usage: test_jsonsink_input() without return types