code: def test_html_diff(self):
      # Check SF patch 914575 for generating HTML differences
      f1a = (patch914575_from1 + "123\n" * 10) * 3
      t1a = (patch914575_to1 + "123\n" * 10) * 3
      f1b = "456\n" * 10 + f1a
      t1b = "456\n" * 10 + t1a
      f1a = f1a.splitlines()
      t1a = t1a.splitlines()
      f1b = f1b.splitlines()
      t1b = t1b.splitlines()
      f2 = patch914575_from2.splitlines()
      t2 = patch914575_to2.splitlines()
      f3 = patch914575_from3
      t3 = patch914575_to3
      i = difflib.HtmlDiff()
      j = difflib.HtmlDiff(tabsize=2)
      k = difflib.HtmlDiff(wrapcolumn=14)
  
      full = i.make_file(
          f1a, t1a, "from", "to", context=False, numlines=5
      )
      tables = "\n".join(
          [
              "<h2>Context (first diff within numlines=5(default))</h2>",
              i.make_table(f1a, t1a, "from", "to", context=True),
              "<h2>Context (first diff after numlines=5(default))</h2>",
              i.make_table(f1b, t1b, "from", "to", context=True),
              "<h2>Context (numlines=6)</h2>",
              i.make_table(
                  f1a, t1a, "from", "to", context=True, numlines=6
              ),
              "<h2>Context (numlines=0)</h2>",
              i.make_table(
                  f1a, t1a, "from", "to", context=True, numlines=0
              ),
              "<h2>Same Context</h2>",
              i.make_table(f1a, f1a, "from", "to", context=True),
              "<h2>Same Full</h2>",
              i.make_table(f1a, f1a, "from", "to", context=False),
              "<h2>Empty Context</h2>",
              i.make_table([], [], "from", "to", context=True),
              "<h2>Empty Full</h2>",
              i.make_table([], [], "from", "to", context=False),
              "<h2>tabsize=2</h2>",
              j.make_table(f2, t2),
              "<h2>tabsize=default</h2>",
              i.make_table(f2, t2),
              "<h2>Context (wrapcolumn=14,numlines=0)</h2>",
              k.make_table(
                  f3.splitlines(),
                  t3.splitlines(),
                  context=True,
                  numlines=0,
              ),
              "<h2>wrapcolumn=14,splitlines()</h2>",
              k.make_table(f3.splitlines(), t3.splitlines()),
              "<h2>wrapcolumn=14,splitlines(True)</h2>",
              k.make_table(f3.splitlines(True), t3.splitlines(True)),
          ]
      )
      actual = full.replace("</body>", "\n%s\n</body>" % tables)
  
      # temporarily uncomment next two lines to baseline this test
      # with open('test_difflib_expect.html','w') as fp:
      #    fp.write(actual)
  
      with open(
          findfile("test_difflib_expect.html"), encoding="utf-8"
      ) as fp:
          self.assertEqual(actual, fp.read())
  
imports: import difflib
  from test.support import findfile
  import unittest
  import doctest
  import sys
label_desc: Use image node_id 1 for calling the TestSFpatches obj's underlying member method code with example usage: obj.test_html_diff() without return types