code: def test_docs(req):
      request = DataRequest(request=req)
      docs = request.docs
      assert isinstance(docs, DocumentArray)
      assert len(docs) == 1
  
imports: import copy
  import pytest
  from docarray import Document, DocumentArray
  from google.protobuf.json_format import MessageToDict, MessageToJson
  from jina.excepts import BadRequestType
  from jina.helper import random_identity
  from jina.proto import jina_pb2
  from jina.proto.serializer import DataRequestProto
  from jina.types.request.data import DataRequest, Response
label_desc: Use image node_id 4 for calling a global function with example usage: test_docs(req) without return types