class_docstr: GRPCServer test
class_docstr_tok: ["GRPCServer","test"]
code: def test_default(self):
      self.server = GRPCServer(
          api_service.build_service(
              [(lambda x: x, "/echo"), (lambda x: x + 1, "/add_one")]
          )
      )
      self.server.start("localhost", 50001)
  
      client = Client("localhost", 50001)
  
      response = client("/echo", 1)
      self.assertEqual(from_json(response.content), 1)
  
      response = client("/add_one", 1)
      self.assertEqual(from_json(response.content), 2)
      client.close()
  
      async def run_async():
          async with AsyncClient("localhost", 50001) as aclient:
              response = await aclient("/add_one", 1)
              self.assertEqual(from_json(response.content), 2)
  
      asyncio.run(run_async())
  
imports: import unittest
  import typing
  import asyncio
  from pydantic import BaseModel
  import numpy
  from towhee import api_service, pipe
  from towhee.serve.grpc.server import GRPCServer
  from towhee.serve.grpc.client import Client, AsyncClient
  from towhee.serve.io import JSON, NDARRAY, BYTES
  from towhee.utils.serializer import from_json
label_desc: Use image node_id 2 for calling the TestGRPC obj's underlying member method code with example usage: obj.test_default() without return types