class_docstr: Test towhee.api_service.build_service
code: def test_default(self):
      service = api_service.build_service(
          [(lambda x: x, "/echo"), (lambda x: x + 1, "/add_one")]
      )
      self.assertEqual(len(service.routers), 2)
      self.assertEqual(service.routers[0].input_model, None)
      self.assertEqual(service.routers[0].output_model, None)
      self.assertEqual(service.routers[0].path, "/echo")
      self.assertEqual(service.routers[1].input_model, None)
      self.assertEqual(service.routers[1].output_model, None)
      self.assertEqual(service.routers[1].path, "/add_one")
  
file_path: towhee/tests/unittests/serve/test_api_service.py
imports: from typing import List
  import unittest
  from towhee import api_service
label_desc: Use image node_id 1 for calling the TestBuilder obj's underlying member method code with example usage: obj.test_default() without return types