code: def test_html_cell(self):
      tc = new_text_cell("html", "hi", "hi")
      self.assertEqual(tc.source, "hi")
      self.assertEqual(tc.rendered, "hi")
  
imports: from __future__ import annotations
  from unittest import TestCase
  from nbformat.v2.nbbase import NotebookNode, new_author, new_code_cell, new_metadata, new_notebook, new_output, new_text_cell, new_worksheet
label_desc: Use image node_id 5 for calling the TestCell obj's underlying member method code with example usage: obj.test_html_cell() without return types