class_docstr: Test server
class_docstr_tok: ["Test","server"]
code: def test_no_input(self):
      service = api_service.APIService(desc="test")
  
      @service.api(path="/no_input")
      def test():
          return "No input"
  
      server = HTTPServer(service)
      client = TestClient(server.app)
      response = client.post("/no_input")
      self.assertEqual(from_json(response.content), "No input")
  
file_path: towhee/tests/unittests/serve/http/test_http.py
imports: import unittest
  import typing
  from pydantic import BaseModel
  import numpy
  from towhee.utils.thirdparty.fastapi_utils import fastapi
  from fastapi.testclient import TestClient
  from towhee import api_service, pipe
  from towhee.serve.http.server import HTTPServer
  from towhee.serve.io import JSON, NDARRAY, BYTES
  from towhee.utils.serializer import to_json, from_json
label_desc: Use image node_id 7 for calling the TestHTTPServer obj's underlying member method code with example usage: obj.test_no_input() and returns: str