anchor.diff:                  {start_tag,<<"div">>,[{<<"class">>,<<"c">>}],false},
                   {end_tag,<<"div">>},
                   {end_tag,<<"div">>}],
  -    {<<"html">>, [],
  -     [{<<"head">>, [], []},
  -      {<<"body">>, [],
  -       [{<<"div">>, [{<<"class">>, <<"a">>}], [{<<"a">>, [{<<"name">>, <<"#anchor">>}], []}]},
  -        {<<"div">>, [{<<"class">>, <<"b">>}], [{<<"div">>, [{<<"class">>, <<"c">>}], []}]}
  -       ]}]} = parse_tokens(D4),
  +    ?assertEqual(
  +       {<<"html">>, [],
  +        [{<<"head">>, [], []},
  +         {<<"body">>, [],
  +          [{<<"div">>, [{<<"class">>, <<"a">>}], [{<<"a">>, [{<<"name">>, <<"#anchor">>}], []}]},
  +           {<<"div">>, [{<<"class">>, <<"b">>}], [{<<"div">>, [{<<"class">>, <<"c">>}], []}]}
  +          ]}]},
  +       parse_tokens(D4)),
       D5 = [{start_tag,<<"html">>,[],false},
             {data,<<"\n">>,true},
             {data,<<"boo">>,false},
             {data,<<"hoo">>,false},
             {data,<<"\n">>,true},
             {end_tag,<<"html">>}],
  -    {<<"html">>, [], [<<"\nboohoo\n">>]} = parse_tokens(D5),
  +    ?assertEqual(
  +       {<<"html">>, [], [<<"\nboohoo\n">>]},
  +       parse_tokens(D5)),
       D6 = [{start_tag,<<"html">>,[],false},
             {data,<<"\n">>,true},
             {data,<<"\n">>,true},
             {end_tag,<<"html">>}],
  -    {<<"html">>, [], []} = parse_tokens(D6),
  +    ?assertEqual(
  +       {<<"html">>, [], []},
  +       parse_tokens(D6)),
       D7 = [{start_tag,<<"html">>,[],false},
             {start_tag,<<"ul">>,[],false},
             {start_tag,<<"li">>,[],false},
  
positive.code: to_tokens(T={comment, _}) ->
      [T];
  to_tokens({Tag0, Acc}) ->
      to_tokens({Tag0, [], Acc});
  to_tokens({Tag0, Attrs, Acc}) ->
      Tag = to_tag(Tag0),
  
negative.code:           {data,<<"asdf">>,false},
            {end_tag,<<"ul">>},
            {end_tag,<<"html">>}],
      ?assertEqual(
         {<<"html">>, [],
          [{<<"ul">>, [],
            [{<<"li">>, [], [<<"word">>]},
             {<<"li">>, [], [<<"up">>]},
             {<<"li">>, [], [<<"fdsa">>,{<<"br">>, [], []}, <<"asdf">>]}]}]},
         parse_tokens(D7)),
      ok.
  
  destack_test() ->
  