class_docstr: Unit tests for Visualizer.
class_docstr_tok: ["Unit","tests","for","Visualizer","."]
code: def test_result(self):
      p = (
          pipe.input("a")
          .map("a", "b", lambda x: x + 1)
          .output("a", "b")
      )
  
      v = p.debug(1, tracer=True)
      res = v.result.get()
  
      self.assertIsInstance(v.result, DataQueue)
      self.assertEqual(res[0], 1)
      self.assertEqual(res[1], 2)
  
file_path: towhee/tests/unittests/tools/test_visualizer.py
imports: import unittest
  from towhee import pipe
  from towhee.tools import visualizer
  from towhee.tools.visualizer import Visualizer
  from towhee.runtime.data_queue import DataQueue
label_desc: Use image node_id 5 for calling the TestVisualizer obj's underlying member method code with example usage: obj.test_result() without return types