code: def test_tooltip_render(ttips, styler):
      # GH 21266
      result = styler.set_tooltips(ttips).to_html()
  
      # test tooltip table level class
      assert "#T_ .pd-t {\n  visibility: hidden;\n" in result
  
      # test 'Min' tooltip added
      assert (
          "#T_ #T__row0_col0:hover .pd-t {\n  visibility: visible;\n}"
          in result
      )
      assert (
          '#T_ #T__row0_col0 .pd-t::after {\n  content: "Min";\n}'
          in result
      )
      assert (
          'class="data row0 col0" >0<span class="pd-t"></span></td>'
          in result
      )
  
      # test 'Max' tooltip added
      assert (
          "#T_ #T__row0_col2:hover .pd-t {\n  visibility: visible;\n}"
          in result
      )
      assert (
          '#T_ #T__row0_col2 .pd-t::after {\n  content: "Max";\n}'
          in result
      )
      assert (
          'class="data row0 col2" >2<span class="pd-t"></span></td>'
          in result
      )
  
      # test Nan, empty string and bad column ignored
      assert (
          "#T_ #T__row1_col0:hover .pd-t {\n  visibility: visible;\n}"
          not in result
      )
      assert (
          "#T_ #T__row1_col1:hover .pd-t {\n  visibility: visible;\n}"
          not in result
      )
      assert (
          "#T_ #T__row0_col1:hover .pd-t {\n  visibility: visible;\n}"
          not in result
      )
      assert (
          "#T_ #T__row1_col2:hover .pd-t {\n  visibility: visible;\n}"
          not in result
      )
      assert "Bad-Col" not in result
  
file_path: pandas/pandas/tests/io/formats/style/test_tooltip.py
imports: import numpy
  import pytest
  from pandas import DataFrame
  from pandas.io.formats.style import Styler
label_desc: Use image node_id 3 for calling a global function with example usage: test_tooltip_render(ttips, styler) without return types