diff --git a/test/readers_writers/sample_html_writer.lua b/test/readers_writers/sample_html_writer.lua
deleted file mode 100644
index 655ae45..0000000
--- a/test/readers_writers/sample_html_writer.lua
+++ /dev/null
@@ -1,371 +0,0 @@
--- EXAMPLE from https://pandoc.org/custom-writers.html
--- This is a sample custom writer for pandoc.  It produces output
--- that is very similar to that of pandoc's HTML writer.
--- There is one new feature: code blocks marked with class 'dot'
--- are piped through graphviz and images are included in the HTML
--- output using 'data:' URLs. The image format can be controlled
--- via the `image_format` metadata field.
---
--- Invoke with: pandoc -t sample.lua
---
--- Note:  you need not have lua installed on your system to use this
--- custom writer.  However, if you do have lua installed, you can
--- use it to test changes to the script.  'lua sample.lua' will
--- produce informative error messages if your code contains
--- syntax errors.
-
-local pipe = pandoc.pipe
-local stringify = (require 'pandoc.utils').stringify
-
--- The global variable PANDOC_DOCUMENT contains the full AST of
--- the document which is going to be written. It can be used to
--- configure the writer.
-local meta = PANDOC_DOCUMENT.meta
-
--- Choose the image format based on the value of the
--- `image_format` meta value.
-local image_format = meta.image_format
-  and stringify(meta.image_format)
-  or 'png'
-local image_mime_type = ({
-    jpeg = 'image/jpeg',
-    jpg = 'image/jpeg',
-    gif = 'image/gif',
-    png = 'image/png',
-    svg = 'image/svg+xml',
-  })[image_format]
-  or error('unsupported image format `' .. image_format .. '`')
-
--- Character escaping
-local function escape(s, in_attribute)
-  return s:gsub('[<>&"\']',
-    function(x)
-      if x == '<' then
-        return '&lt;'
-      elseif x == '>' then
-        return '&gt;'
-      elseif x == '&' then
-        return '&amp;'
-      elseif in_attribute and x == '"' then
-        return '&quot;'
-      elseif in_attribute and x == "'" then
-        return '&#39;'
-      else
-        return x
-      end
-    end)
-end
-
--- Helper function to convert an attributes table into
--- a string that can be put into HTML tags.
-local function attributes(attr)
-  local attr_table = {}
-  for x,y in pairs(attr) do
-    if y and y ~= '' then
-      table.insert(attr_table, ' ' .. x .. '="' .. escape(y,true) .. '"')
-    end
-  end
-  return table.concat(attr_table)
-end
-
--- Table to store footnotes, so they can be included at the end.
-local notes = {}
-
--- Blocksep is used to separate block elements.
-function Blocksep()
-  return '\n\n'
-end
-
--- This function is called once for the whole document. Parameters:
--- body is a string, metadata is a table, variables is a table.
--- This gives you a fragment.  You could use the metadata table to
--- fill variables in a custom lua template.  Or, pass `--template=...`
--- to pandoc, and pandoc will do the template processing as usual.
-function Doc(body, metadata, variables)
-  local buffer = {}
-  local function add(s)
-    table.insert(buffer, s)
-  end
-  add(body)
-  if #notes > 0 then
-    add('<ol class="footnotes">')
-    for _,note in pairs(notes) do
-      add(note)
-    end
-    add('</ol>')
-  end
-  return table.concat(buffer,'\n') .. '\n'
-end
-
--- The functions that follow render corresponding pandoc elements.
--- s is always a string, attr is always a table of attributes, and
--- items is always an array of strings (the items in a list).
--- Comments indicate the types of other variables.
-
-function Str(s)
-  return escape(s)
-end
-
-function Space()
-  return ' '
-end
-
-function SoftBreak()
-  return '\n'
-end
-
-function LineBreak()
-  return '<br/>'
-end
-
-function Emph(s)
-  return '<em>' .. s .. '</em>'
-end
-
-function Strong(s)
-  return '<strong>' .. s .. '</strong>'
-end
-
-function Subscript(s)
-  return '<sub>' .. s .. '</sub>'
-end
-
-function Superscript(s)
-  return '<sup>' .. s .. '</sup>'
-end
-
-function SmallCaps(s)
-  return '<span style="font-variant: small-caps;">' .. s .. '</span>'
-end
-
-function Strikeout(s)
-  return '<del>' .. s .. '</del>'
-end
-
-function Link(s, tgt, tit, attr)
-  return '<a href="' .. escape(tgt,true) .. '" title="' ..
-         escape(tit,true) .. '"' .. attributes(attr) .. '>' .. s .. '</a>'
-end
-
-function Image(s, src, tit, attr)
-  return '<img src="' .. escape(src,true) .. '" title="' ..
-         escape(tit,true) .. '"/>'
-end
-
-function Code(s, attr)
-  return '<code' .. attributes(attr) .. '>' .. escape(s) .. '</code>'
-end
-
-function InlineMath(s)
-  return '\\(' .. escape(s) .. '\\)'
-end
-
-function DisplayMath(s)
-  return '\\[' .. escape(s) .. '\\]'
-end
-
-function SingleQuoted(s)
-  return '&lsquo;' .. s .. '&rsquo;'
-end
-
-function DoubleQuoted(s)
-  return '&ldquo;' .. s .. '&rdquo;'
-end
-
-function Note(s)
-  local num = #notes + 1
-  -- insert the back reference right before the final closing tag.
-  s = string.gsub(s,
-          '(.*)</', '%1 <a href="#fnref' .. num ..  '">&#8617;</a></')
-  -- add a list item with the note to the note table.
-  table.insert(notes, '<li id="fn' .. num .. '">' .. s .. '</li>')
-  -- return the footnote reference, linked to the note.
-  return '<a id="fnref' .. num .. '" href="#fn' .. num ..
-            '"><sup>' .. num .. '</sup></a>'
-end
-
-function Span(s, attr)
-  return '<span' .. attributes(attr) .. '>' .. s .. '</span>'
-end
-
-function RawInline(format, str)
-  if format == 'html' then
-    return str
-  else
-    return ''
-  end
-end
-
-function Cite(s, cs)
-  local ids = {}
-  for _,cit in ipairs(cs) do
-    table.insert(ids, cit.citationId)
-  end
-  return '<span class="cite" data-citation-ids="' .. table.concat(ids, ',') ..
-    '">' .. s .. '</span>'
-end
-
-function Plain(s)
-  return s
-end
-
-function Para(s)
-  return '<p>' .. s .. '</p>'
-end
-
--- lev is an integer, the header level.
-function Header(lev, s, attr)
-  return '<h' .. lev .. attributes(attr) ..  '>' .. s .. '</h' .. lev .. '>'
-end
-
-function BlockQuote(s)
-  return '<blockquote>\n' .. s .. '\n</blockquote>'
-end
-
-function HorizontalRule()
-  return "<hr/>"
-end
-
-function LineBlock(ls)
-  return '<div style="white-space: pre-line;">' .. table.concat(ls, '\n') ..
-         '</div>'
-end
-
-function CodeBlock(s, attr)
-  -- If code block has class 'dot', pipe the contents through dot
-  -- and base64, and include the base64-encoded png as a data: URL.
-  if attr.class and string.match(' ' .. attr.class .. ' ',' dot ') then
-    local img = pipe('base64', {}, pipe('dot', {'-T' .. image_format}, s))
-    return '<img src="data:' .. image_mime_type .. ';base64,' .. img .. '"/>'
-  -- otherwise treat as code (one could pipe through a highlighter)
-  else
-    return '<pre><code' .. attributes(attr) .. '>' .. escape(s) ..
-           '</code></pre>'
-  end
-end
-
-function BulletList(items)
-  local buffer = {}
-  for _, item in pairs(items) do
-    table.insert(buffer, '<li>' .. item .. '</li>')
-  end
-  return '<ul>\n' .. table.concat(buffer, '\n') .. '\n</ul>'
-end
-
-function OrderedList(items)
-  local buffer = {}
-  for _, item in pairs(items) do
-    table.insert(buffer, '<li>' .. item .. '</li>')
-  end
-  return '<ol>\n' .. table.concat(buffer, '\n') .. '\n</ol>'
-end
-
-function DefinitionList(items)
-  local buffer = {}
-  for _,item in pairs(items) do
-    local k, v = next(item)
-    table.insert(buffer, '<dt>' .. k .. '</dt>\n<dd>' ..
-                   table.concat(v, '</dd>\n<dd>') .. '</dd>')
-  end
-  return '<dl>\n' .. table.concat(buffer, '\n') .. '\n</dl>'
-end
-
--- Convert pandoc alignment to something HTML can use.
--- align is AlignLeft, AlignRight, AlignCenter, or AlignDefault.
-local function html_align(align)
-  if align == 'AlignLeft' then
-    return 'left'
-  elseif align == 'AlignRight' then
-    return 'right'
-  elseif align == 'AlignCenter' then
-    return 'center'
-  else
-    return 'left'
-  end
-end
-
-function CaptionedImage(src, tit, caption, attr)
-  if #caption == 0 then
-    return '<p><img src="' .. escape(src,true) .. '" id="' .. attr.id ..
-      '"/></p>'
-  else
-    local ecaption = escape(caption)
-    return '<figure>\n<img src="' .. escape(src,true) ..
-        '" id="' .. attr.id .. '" alt="' .. ecaption  .. '"/>' ..
-        '<figcaption>' .. ecaption .. '</figcaption>\n</figure>'
-  end
-end
-
--- Caption is a string, aligns is an array of strings,
--- widths is an array of floats, headers is an array of
--- strings, rows is an array of arrays of strings.
-function Table(caption, aligns, widths, headers, rows)
-  local buffer = {}
-  local function add(s)
-    table.insert(buffer, s)
-  end
-  add('<table>')
-  if caption ~= '' then
-    add('<caption>' .. escape(caption) .. '</caption>')
-  end
-  if widths and widths[1] ~= 0 then
-    for _, w in pairs(widths) do
-      add('<col width="' .. string.format('%.0f%%', w * 100) .. '" />')
-    end
-  end
-  local header_row = {}
-  local empty_header = true
-  for i, h in pairs(headers) do
-    local align = html_align(aligns[i])
-    table.insert(header_row,'<th align="' .. align .. '">' .. h .. '</th>')
-    empty_header = empty_header and h == ''
-  end
-  if not empty_header then
-    add('<tr class="header">')
-    for _,h in pairs(header_row) do
-      add(h)
-    end
-    add('</tr>')
-  end
-  local class = 'even'
-  for _, row in pairs(rows) do
-    class = (class == 'even' and 'odd') or 'even'
-    add('<tr class="' .. class .. '">')
-    for i,c in pairs(row) do
-      add('<td align="' .. html_align(aligns[i]) .. '">' .. c .. '</td>')
-    end
-    add('</tr>')
-  end
-  add('</table>')
-  return table.concat(buffer,'\n')
-end
-
-function RawBlock(format, str)
-  if format == 'html' then
-    return str
-  else
-    return ''
-  end
-end
-
-function Div(s, attr)
-  return '<div' .. attributes(attr) .. '>\n' .. s .. '</div>'
-end
-
-function Writer (doc, opts)
-  PANDOC_DOCUMENT = doc
-  PANDOC_WRITER_OPTIONS = opts
-  loadfile(PANDOC_SCRIPT_FILE)()
-  return pandoc.write_classic(doc, opts)
-end
-
--- The following code will produce runtime warnings when you haven't defined
--- all of the functions you need for the custom writer, so it's useful
--- to include when you're working on a writer.
-local meta = {}
-meta.__index =
-  function(_, key)
-    io.stderr:write(string.format("WARNING: Undefined function '%s'\n",key))
-    return function() return '' end
-  end
-setmetatable(_G, meta)