From 28faff1eb2af8c9db8b39a74c4ee9d7f49f6f9b4 Mon Sep 17 00:00:00 2001
From: Mayel de Borniol <git@mayel.space>
Date: Thu, 26 Dec 2024 15:05:36 +0000
Subject: [PATCH] WIP for https://github.com/elixir-lang/ex_doc/pull/1976

---
 lib/ex_doc.ex                                 |   1 +
 lib/ex_doc/cli.ex                             |   2 +-
 .../html/templates/footer_template.eex        |   6 +
 .../html/templates/module_template.eex        |   8 +
 lib/ex_doc/formatter/markdown.ex              |  49 +++--
 lib/ex_doc/formatter/markdown/assets.ex       |   2 +-
 lib/ex_doc/formatter/markdown/templates.ex    |  77 +++-----
 .../templates/nav_grouped_item_template.eex   |   8 +
 .../markdown/templates/nav_item_template.eex  |   6 +
 .../markdown/templates/nav_template.eex       |   9 +
 .../formatter/markdown/templates_test.exs     | 157 ++++++++++++++++
 test/ex_doc/formatter/markdown_test.exs       | 173 ++++++++++++++++++
 12 files changed, 425 insertions(+), 73 deletions(-)
 create mode 100644 lib/ex_doc/formatter/markdown/templates/nav_grouped_item_template.eex
 create mode 100644 lib/ex_doc/formatter/markdown/templates/nav_item_template.eex
 create mode 100644 lib/ex_doc/formatter/markdown/templates/nav_template.eex
 create mode 100644 test/ex_doc/formatter/markdown/templates_test.exs
 create mode 100644 test/ex_doc/formatter/markdown_test.exs

diff --git a/lib/ex_doc.ex b/lib/ex_doc.ex
index c108c3560..4fdf725a3 100644
--- a/lib/ex_doc.ex
+++ b/lib/ex_doc.ex
@@ -44,6 +44,7 @@ defmodule ExDoc do
     if Code.ensure_loaded?(modname) do
       modname
     else
+      IO.inspect(modname)
       raise "formatter module #{inspect(argname)} not found"
     end
   end
diff --git a/lib/ex_doc/cli.ex b/lib/ex_doc/cli.ex
index 5573ede94..2d8e14ef1 100644
--- a/lib/ex_doc/cli.ex
+++ b/lib/ex_doc/cli.ex
@@ -103,7 +103,7 @@ defmodule ExDoc.CLI do
   defp normalize_formatters(opts) do
     formatters =
       case Keyword.get_values(opts, :formatter) do
-        [] -> opts[:formatters] || ["html", "epub", "markdown"]
+        [] -> opts[:formatters] || ["html", "epub"]
         values -> values
       end
 
diff --git a/lib/ex_doc/formatter/html/templates/footer_template.eex b/lib/ex_doc/formatter/html/templates/footer_template.eex
index 5488a0212..2f0042019 100644
--- a/lib/ex_doc/formatter/html/templates/footer_template.eex
+++ b/lib/ex_doc/formatter/html/templates/footer_template.eex
@@ -22,6 +22,12 @@
               Download ePub version
             </a>
           <% end %>
+
+          <%= if "markdown" in config.formatters do %>
+            <a href="<%= config.project %>-markdown.zip" title="Markdown version">
+              Download Markdown version
+            </a>
+          <% end %>
         </span>
       </p>
 
diff --git a/lib/ex_doc/formatter/html/templates/module_template.eex b/lib/ex_doc/formatter/html/templates/module_template.eex
index 4f2824c16..bdb31d715 100644
--- a/lib/ex_doc/formatter/html/templates/module_template.eex
+++ b/lib/ex_doc/formatter/html/templates/module_template.eex
@@ -9,6 +9,14 @@
         <span class="sr-only">View Source</span>
       </a>
     <% end %>
+    <%= if "markdown" in config.formatters do %>
+      <a href="<%= config.project %>-markdown.zip" title="Markdown version">
+        <%= IO.inspect(module).title %>
+        <i class="ri-markdown-line" aria-hidden="true"></i>
+        <span class="sr-only">Download Markdown version</span>
+      </a>
+    <% end %>
+
     <span translate="no"><%= module.title %></span> <%= module_type(module) %>
     <small class="app-vsn" translate="no">(<%= config.project %> v<%= config.version %>)</small>
     <%= for annotation <- module.annotations do %>
diff --git a/lib/ex_doc/formatter/markdown.ex b/lib/ex_doc/formatter/markdown.ex
index 381b42041..ca0e49178 100644
--- a/lib/ex_doc/formatter/markdown.ex
+++ b/lib/ex_doc/formatter/markdown.ex
@@ -1,7 +1,6 @@
-defmodule ExDoc.Formatter.Markdown do
+defmodule ExDoc.Formatter.MARKDOWN do
   @moduledoc false
 
-  @mimetype "text/markdown"
   @assets_dir "MD/assets"
   alias __MODULE__.{Assets, Templates}
   alias ExDoc.Formatter.HTML
@@ -28,24 +27,24 @@ defmodule ExDoc.Formatter.Markdown do
 
     extras =
       config
-      |> HTML.build_extras(".xhtml")
+      |> HTML.build_extras(".md")
       |> Enum.chunk_by(& &1.group)
       |> Enum.map(&{hd(&1).group, &1})
 
     config = %{config | extras: extras}
 
-    static_files = HTML.generate_assets("MD", default_assets(config), config)
-    HTML.generate_logo(@assets_dir, config)
-    HTML.generate_cover(@assets_dir, config)
-
-    # generate_nav(config, nodes_map)
+    generate_nav(config, nodes_map) 
     generate_extras(config)
     generate_list(config, nodes_map.modules)
     generate_list(config, nodes_map.tasks)
 
-    {:ok, epub} = generate_zip(config.output)
-    File.rm_rf!(config.output)
-    Path.relative_to_cwd(epub)
+    # if config[:generate_zip] do # TODO: add a command line flag?
+    #   {:ok, zip} = generate_zip(config.output)
+    #   File.rm_rf!(config.output)
+    #   Path.relative_to_cwd(zip)
+    # else
+      config.output |> Path.join("index.md") |> Path.relative_to_cwd()
+    # end
   end
 
   defp normalize_config(config) do
@@ -57,6 +56,23 @@ defmodule ExDoc.Formatter.Markdown do
     %{config | output: output}
   end
 
+  defp normalize_output(output) do
+    output
+    |> String.replace(~r/\r\n|\r|\n/, "\n")
+    |> String.replace(~r/\n{2,}/, "\n") 
+  end
+
+  defp generate_nav(config, nodes) do
+    nodes =
+      Map.update!(nodes, :modules, fn modules ->
+        modules |> Enum.chunk_by(& &1.group) |> Enum.map(&{hd(&1).group, &1})
+      end)
+
+    content = Templates.nav_template(config, nodes)
+    |> normalize_output()
+    File.write("#{config.output}/MD/index.md", content)
+  end
+
   defp generate_extras(config) do
     for {_title, extras} <- config.extras do
       Enum.each(extras, fn %{id: id, title: title, title_content: _title_content, source: content} ->
@@ -66,6 +82,7 @@ defmodule ExDoc.Formatter.Markdown do
 
         #{content}
         """
+        |> normalize_output()
 
         if File.regular?(output) do
           Utils.warn("file #{Path.relative_to_cwd(output)} already exists", [])
@@ -77,8 +94,6 @@ defmodule ExDoc.Formatter.Markdown do
   end
 
 
-
-
   defp generate_list(config, nodes) do
     nodes
     |> Task.async_stream(&generate_module_page(&1, config), timeout: :infinity)
@@ -99,13 +114,6 @@ defmodule ExDoc.Formatter.Markdown do
 
   ## Helpers
 
-  defp default_assets(config) do
-    [
-      {Assets.dist(config.proglang), "MD/dist"},
-      {Assets.metainfo(), "META-INF"}
-    ]
-  end
-
   defp files_to_add(path) do
     Enum.reduce(Path.wildcard(Path.join(path, "**/*")), [], fn file, acc ->
       case File.read(file) do
@@ -120,6 +128,7 @@ defmodule ExDoc.Formatter.Markdown do
 
   defp generate_module_page(module_node, config) do
     content = Templates.module_page(config, module_node)
+    |> normalize_output()
     File.write("#{config.output}/MD/#{module_node.id}.md", content)
   end
 
diff --git a/lib/ex_doc/formatter/markdown/assets.ex b/lib/ex_doc/formatter/markdown/assets.ex
index 2a3041226..5001fae5b 100644
--- a/lib/ex_doc/formatter/markdown/assets.ex
+++ b/lib/ex_doc/formatter/markdown/assets.ex
@@ -1,4 +1,4 @@
-defmodule ExDoc.Formatter.Markdown.Assets do
+defmodule ExDoc.Formatter.MARKDOWN.Assets do
   @moduledoc false
 
   defmacrop embed_pattern(pattern) do
diff --git a/lib/ex_doc/formatter/markdown/templates.ex b/lib/ex_doc/formatter/markdown/templates.ex
index ab9c5b498..da57e5341 100644
--- a/lib/ex_doc/formatter/markdown/templates.ex
+++ b/lib/ex_doc/formatter/markdown/templates.ex
@@ -1,10 +1,10 @@
-defmodule ExDoc.Formatter.Markdown.Templates do
+defmodule ExDoc.Formatter.MARKDOWN.Templates do
   @moduledoc false
 
   require EEx
 
   import ExDoc.Utils,
-    only: [before_closing_body_tag: 2, before_closing_head_tag: 2, h: 1, text_to_id: 1]
+    only: [before_closing_body_tag: 2, h: 1, text_to_id: 1]
 
   alias ExDoc.Formatter.HTML.Templates, as: H
 
@@ -119,48 +119,34 @@ defmodule ExDoc.Formatter.Markdown.Templates do
     trim: true
   )
 
-  # @doc """
-  # Creates the table of contents.
-
-  # This template follows the EPUB Navigation Document Definition.
-
-  # See http://www.idpf.org/epub/30/spec/epub30-contentdocs.html#sec-xhtml-nav.
-  # """
-  # EEx.function_from_file(
-  #   :def,
-  #   :nav_template,
-  #   Path.expand("templates/nav_template.eex", __DIR__),
-  #   [:config, :nodes],
-  #   trim: true
-  # )
+  @doc """
+  Creates the table of contents.
 
-  # @doc """
-  # Creates a new chapter when the user provides additional files.
-  # """
-  # EEx.function_from_file(
-  #   :def,
-  #   :extra_template,
-  #   Path.expand("templates/extra_template.eex", __DIR__),
-  #   [:config, :title, :title_content, :content],
-  #   trim: true
-  # )
+  """
+  EEx.function_from_file(
+    :def,
+    :nav_template,
+    Path.expand("templates/nav_template.eex", __DIR__),
+    [:config, :nodes],
+    trim: true
+  )
 
 
-  # EEx.function_from_file(
-  #   :defp,
-  #   :nav_item_template,
-  #   Path.expand("templates/nav_item_template.eex", __DIR__),
-  #   [:name, :nodes],
-  #   trim: true
-  # )
+  EEx.function_from_file(
+    :defp,
+    :nav_item_template,
+    Path.expand("templates/nav_item_template.eex", __DIR__),
+    [:name, :nodes],
+    trim: true
+  )
 
-  # EEx.function_from_file(
-  #   :defp,
-  #   :nav_grouped_item_template,
-  #   Path.expand("templates/nav_grouped_item_template.eex", __DIR__),
-  #   [:nodes],
-  #   trim: true
-  # )
+  EEx.function_from_file(
+    :defp,
+    :nav_grouped_item_template,
+    Path.expand("templates/nav_grouped_item_template.eex", __DIR__),
+    [:nodes],
+    trim: true
+  )
 
   # EEx.function_from_file(
   #   :defp,
@@ -170,17 +156,6 @@ defmodule ExDoc.Formatter.Markdown.Templates do
   #   trim: true
   # )
 
-  # "templates/media-types.txt"
-  # |> Path.expand(__DIR__)
-  # |> File.read!()
-  # |> String.split("\n", trim: true)
-  # |> Enum.each(fn line ->
-  #   [extension, media] = String.split(line, ",")
-
-  #   def media_type("." <> unquote(extension)) do
-  #     unquote(media)
-  #   end
-  # end)
 
   # def media_type(_arg), do: nil
 
diff --git a/lib/ex_doc/formatter/markdown/templates/nav_grouped_item_template.eex b/lib/ex_doc/formatter/markdown/templates/nav_grouped_item_template.eex
new file mode 100644
index 000000000..874ebdbfd
--- /dev/null
+++ b/lib/ex_doc/formatter/markdown/templates/nav_grouped_item_template.eex
@@ -0,0 +1,8 @@
+<%= for {title, nodes} <- nodes do %>
+<%= if title do %>
+- <%=h to_string(title) %>
+<% end %>
+<%= for node <- nodes do %>
+  - [<%=h node.title %>](<%= URI.encode node.id %>.md)
+<% end %>
+<% end %>
diff --git a/lib/ex_doc/formatter/markdown/templates/nav_item_template.eex b/lib/ex_doc/formatter/markdown/templates/nav_item_template.eex
new file mode 100644
index 000000000..aaa568662
--- /dev/null
+++ b/lib/ex_doc/formatter/markdown/templates/nav_item_template.eex
@@ -0,0 +1,6 @@
+<%= unless Enum.empty?(nodes) do %>
+- <%= name %>
+<%= for node <- nodes do %>
+1. [<%=h node.title %>](<%= URI.encode node.id %>.md)
+<% end %>
+<% end %>
diff --git a/lib/ex_doc/formatter/markdown/templates/nav_template.eex b/lib/ex_doc/formatter/markdown/templates/nav_template.eex
new file mode 100644
index 000000000..aa35d02df
--- /dev/null
+++ b/lib/ex_doc/formatter/markdown/templates/nav_template.eex
@@ -0,0 +1,9 @@
+# Table of contents
+
+<%= nav_grouped_item_template config.extras  %>
+<%= unless Enum.empty?(nodes.modules) do %>
+## Modules
+<%= nav_grouped_item_template nodes.modules  %>    
+<% end %>
+<%= nav_item_template "Mix Tasks", nodes.tasks %>
+<%= before_closing_body_tag(config, :markdown) %>
diff --git a/test/ex_doc/formatter/markdown/templates_test.exs b/test/ex_doc/formatter/markdown/templates_test.exs
new file mode 100644
index 000000000..69c3cbc97
--- /dev/null
+++ b/test/ex_doc/formatter/markdown/templates_test.exs
@@ -0,0 +1,157 @@
+defmodule ExDoc.Formatter.MARKDOWN.TemplatesTest do
+  use ExUnit.Case, async: true
+
+  alias ExDoc.Formatter.HTML
+  alias ExDoc.Formatter.MARKDOWN.Templates
+
+  defp source_url do
+    "https://github.com/elixir-lang/elixir"
+  end
+
+  defp homepage_url do
+    "https://elixir-lang.org"
+  end
+
+  defp doc_config(config \\ []) do
+    default = %ExDoc.Config{
+      project: "Elixir",
+      version: "1.0.1",
+      source_url_pattern: "#{source_url()}/blob/master/%{path}#L%{line}",
+      homepage_url: homepage_url(),
+      source_url: source_url(),
+      output: "test/tmp/markdown_templates"
+    }
+
+    struct(default, config)
+  end
+
+  defp get_module_page(names, config \\ []) do
+    config = doc_config(config)
+    {mods, []} = ExDoc.Retriever.docs_from_modules(names, config)
+    [mod | _] = HTML.render_all(mods, [], ".md", config, highlight_tag: "samp")
+    Templates.module_page(config, mod)
+  end
+
+  setup_all do
+    # File.mkdir_p!("test/tmp/markdown_templates")
+    # File.cp_r!("formatters/markdown", "test/tmp/markdown_templates")
+    :ok
+  end
+
+  describe "content_template/5" do
+    test "includes logo as a resource if specified in the config" do
+      nodes = %{modules: [], tasks: []}
+
+      content =
+        [logo: "my_logo.png"]
+        |> doc_config()
+        |> Templates.content_template(nodes, "uuid", "datetime", _static_files = [])
+
+      assert content =~ ~S|<item id="logo" href="assets/logo.png" media-type="image/png"/>|
+    end
+
+
+    test "includes modules as a resource" do
+      module_node = %ExDoc.ModuleNode{
+        module: XPTOModule,
+        doc: nil,
+        id: "XPTOModule",
+        title: "XPTOModule"
+      }
+
+      nodes = %{modules: [module_node], tasks: []}
+
+      content =
+        Templates.content_template(doc_config(), nodes, "uuid", "datetime", _static_files = [])
+
+      assert content =~
+               ~S|<item id="XPTOModule" href="XPTOModule.md" media-type="application/md+xml" properties="scripted"/>|
+
+      assert content =~ ~S|<itemref idref="XPTOModule"/>|
+    end
+  end
+
+  describe "module_page/2" do
+    test "generates only the module name when there's no more info" do
+      module_node = %ExDoc.ModuleNode{
+        module: XPTOModule,
+        doc: nil,
+        id: "XPTOModule",
+        title: "XPTOModule"
+      }
+
+      content = Templates.module_page(doc_config(), module_node)
+
+      assert content =~ ~r{#\s*XPTOModule\s*}
+    end
+
+    test "outputs the functions and docstrings" do
+      content = get_module_page([CompiledWithDocs])
+
+      assert content =~ ~r{#\s*CompiledWithDocs\s*}
+
+      assert content =~ ~s{# Summary</h1>}
+
+      assert content =~
+               ~r{## .*Example.*}ms
+
+      assert content =~
+               ~r{### .*Example H3 heading.*}ms
+
+      assert content =~
+               ~r{moduledoc.*Example.*<samp class="nc">CompiledWithDocs</samp><samp class="o">\.</samp><samp class="n">example</samp>.*}ms
+
+      assert content =~ ~r{example/2.*Some example}ms
+      assert content =~ ~r{example_without_docs/0.*}ms
+      assert content =~ ~r{example_1/0.*> \(macro\)}ms
+
+      assert content =~ ~s{example(foo, bar \\\\ Baz)}
+    end
+
+    test "outputs function groups" do
+      content =
+        get_module_page([CompiledWithDocs],
+          groups_for_docs: [
+            "Example functions": &(&1[:purpose] == :example),
+            Legacy: &is_binary(&1[:deprecated])
+          ]
+        )
+
+      assert content =~ ~r{.*Example functions}ms
+      assert content =~ ~r{.*Legacy}ms
+    end
+
+
+    ## BEHAVIOURS
+
+    test "outputs behavior and callbacks" do
+      content = get_module_page([CustomBehaviourOne])
+
+      assert content =~
+               ~r{# \s*CustomBehaviourOne\s*behaviour\s*}m
+
+      assert content =~ ~r{Callbacks}
+
+      content = get_module_page([CustomBehaviourTwo])
+
+      assert content =~
+               ~r{# \s*CustomBehaviourTwo\s*behaviour\s*}m
+
+      assert content =~ ~r{Callbacks}
+    end
+
+    ## PROTOCOLS
+
+    test "outputs the protocol type" do
+      content = get_module_page([CustomProtocol])
+      assert content =~ ~r{# \s*CustomProtocol\s*protocol\s*}m
+    end
+
+    ## TASKS
+
+    test "outputs the task type" do
+      content = get_module_page([Mix.Tasks.TaskWithDocs])
+      assert content =~ ~r{# \s*mix task_with_docs\s*}m
+    end
+  end
+end
diff --git a/test/ex_doc/formatter/markdown_test.exs b/test/ex_doc/formatter/markdown_test.exs
new file mode 100644
index 000000000..9af39ecf6
--- /dev/null
+++ b/test/ex_doc/formatter/markdown_test.exs
@@ -0,0 +1,173 @@
+defmodule ExDoc.Formatter.MARKDOWNTest do
+  use ExUnit.Case, async: false
+
+  import ExUnit.CaptureIO
+
+  alias ExDoc.Utils
+
+  @moduletag :tmp_dir
+
+  @before_closing_body_tag_content_md "UNIQUE:<dont-escape>&copy;BEFORE-CLOSING-BODY-TAG-HTML</dont-escape>"
+
+  defp before_closing_body_tag(:markdown), do: @before_closing_body_tag_content_md
+
+  def before_closing_body_tag(:markdown, name), do: "#{name}"
+
+  defp doc_config(%{tmp_dir: tmp_dir} = _context) do
+    [
+      app: :elixir,
+      project: "Elixir",
+      version: "1.0.1",
+      formatter: "markdown",
+      output: tmp_dir <> "/markdown",
+      source_beam: "test/tmp/beam",
+      extras: ["test/fixtures/README.md"],
+      skip_undefined_reference_warnings_on: ["Warnings"]
+    ]
+  end
+
+  defp doc_config(context, config) when is_map(context) and is_list(config) do
+    Keyword.merge(doc_config(context), config)
+  end
+
+  defp generate_docs(config) do
+    ExDoc.generate_docs(config[:project], config[:version], config)
+  end
+
+  defp generate_docs(_context, config) do
+    generate_docs(config)
+  end
+
+
+  test "generates a markdown nav file in the default directory", %{tmp_dir: tmp_dir} = context do
+    generate_docs(doc_config(context))
+    assert File.regular?(tmp_dir <> "/markdown/Elixir/MD/nav.md")
+  end
+
+  test "generates a markdown file with erlang as proglang", %{tmp_dir: tmp_dir} = context do
+    config =
+      context
+      |> doc_config()
+      |> Keyword.put(:proglang, :erlang)
+      |> Keyword.update!(:skip_undefined_reference_warnings_on, &["test/fixtures/README.md" | &1])
+
+    generate_docs(config)
+    assert File.regular?(tmp_dir <> "/markdown/Elixir/MD/nav.md")
+  end
+
+  test "generates a markdown file in specified output directory", %{tmp_dir: tmp_dir} = context do
+    config = doc_config(context, output: tmp_dir <> "/markdown/another_dir", main: "RandomError")
+    generate_docs(config)
+
+    assert File.regular?(tmp_dir <> "/markdown/another_dir/nav.md")
+  end
+
+
+  test "generates the readme file", %{tmp_dir: tmp_dir} = context do
+    config = doc_config(context, main: "README")
+    generate_docs(context, config)
+
+    content = File.read!(tmp_dir <> "/markdown/Elixir/MD/readme.md")
+    assert content =~ ~r{<title>README [^<]*</title>}
+    assert content =~ ~r{<a href="RandomError.xhtml"><code(\sclass="inline")?>RandomError</code>}
+
+    assert content =~
+             ~r{<a href="CustomBehaviourImpl.xhtml#hello/1"><code(\sclass="inline")?>CustomBehaviourImpl.hello/1</code>}
+
+    assert content =~
+             ~r{<a href="TypesAndSpecs.Sub.xhtml"><code(\sclass="inline")?>TypesAndSpecs.Sub</code></a>}
+
+    content = File.read!(tmp_dir <> "/markdown/Elixir/MD/nav.md")
+    assert content =~ ~r{<li><a href="readme.xhtml">README</a></li>}
+  end
+
+  test "uses samp as highlight tag for markdown", %{tmp_dir: tmp_dir} = context do
+    generate_docs(context, doc_config(context))
+
+    assert File.read!(tmp_dir <> "/markdown/Elixir/MD/CompiledWithDocs.md") =~
+             "<samp class=\"nc\">CompiledWithDocs<\/samp>"
+  end
+
+  @example_basenames [
+    # "structural" pages
+    "nav.md",
+    "readme.md",
+    # "module pages"
+    "CompiledWithDocs.md",
+    "CompiledWithDocs.Nested.md"
+  ]
+
+  test "before_closing_*_tags required by the user are in the right place",
+       %{tmp_dir: tmp_dir} = context do
+    generate_docs(
+      context,
+      doc_config(context,
+        before_closing_body_tag: &before_closing_body_tag/1
+      )
+    )
+
+    dir = tmp_dir <> "/markdown/Elixir/MD"
+
+    for basename <- @example_basenames do
+      content = File.read!(Path.join(dir, basename))
+      assert content =~ ~r[#{@before_closing_body_tag_content_md}\s]
+    end
+  end
+
+  test "before_closing_*_tags required by the user are in the right place using map",
+       %{tmp_dir: tmp_dir} = context do
+    generate_docs(
+      context,
+      doc_config(context,
+        before_closing_body_tag: %{markdown: "<p>StaticDemo</p>"}
+      )
+    )
+
+    dir = tmp_dir <> "/markdown/Elixir/MD"
+
+    for basename <- @example_basenames do
+      content = File.read!(Path.join(dir, basename))
+      assert content =~ ~r[<p>StaticDemo</p>\s]
+    end
+  end
+
+  test "before_closing_*_tags required by the user are in the right place using a MFA",
+       %{tmp_dir: tmp_dir} = context do
+    generate_docs(
+      context,
+      doc_config(context,
+        before_closing_body_tag: {__MODULE__, :before_closing_body_tag, ["Demo"]}
+      )
+    )
+
+    dir = tmp_dir <> "/markdown/Elixir/MD"
+
+    for basename <- @example_basenames do
+      content = File.read!(Path.join(dir, basename))
+      assert content =~ ~r[<p>Demo</p>\s]
+    end
+  end
+
+  test "assets required by the user end up in the right place", %{tmp_dir: tmp_dir} = context do
+    File.mkdir_p!("test/tmp/markdown_assets/hello")
+    File.touch!("test/tmp/markdown_assets/hello/world.png")
+    File.touch!("test/tmp/markdown_assets/hello/world.pdf")
+
+    generate_docs(
+      context,
+      doc_config(context,
+        assets: %{"test/tmp/markdown_assets" => "assets"},
+        logo: "test/fixtures/elixir.png",
+        cover: "test/fixtures/elixir.png"
+      )
+    )
+
+    assert File.regular?(tmp_dir <> "/markdown/assets/hello/world.png")
+    assert File.regular?(tmp_dir <> "/markdown/assets/hello/world.pdf")
+    assert File.regular?(tmp_dir <> "/markdown/assets/logo.png")
+    assert File.regular?(tmp_dir <> "/markdown/assets/cover.png")
+  after
+    File.rm_rf!("test/tmp/markdown_assets")
+  end
+
+end