code: def test_datafinder_unpack(tmpdir):
      outdir = tmpdir.strpath
      single_res = os.path.join(outdir, "findme.txt")
      open(single_res, "a").close()
      open(os.path.join(outdir, "dontfindme"), "a").close()
  
      df = nio.DataFinder()
      df.inputs.root_paths = outdir
      df.inputs.match_regex = r".+/(?P<basename>.+)\.txt"
      df.inputs.unpack_single = True
      result = df.run()
      print(result.outputs.out_paths)
      assert result.outputs.out_paths == single_res
  
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 17 for calling a global function with example usage: test_datafinder_unpack(tmpdir) without return types