]> git.madduck.net Git - etc/neomutt.git/blobdiff - .config/neomutt/buildmimetree.py

madduck's git repository

Every one of the projects in this repository is available at the canonical URL git://git.madduck.net/madduck/pub/<projectpath> — see each project's metadata for the exact URL.

All patches and comments are welcome. Please squash your changes to logical commits before using git-format-patch and git-send-email to patches@git.madduck.net. If you'd read over the Git project's submission guidelines and adhered to them, I'd be especially grateful.

SSH access, as well as push access can be individually arranged.

If you use my repositories frequently, consider adding the following snippet to ~/.gitconfig and using the third clone URL listed for each project:

[url "git://git.madduck.net/madduck/"]
  insteadOf = madduck:

buildmimetree.py: make Multipart nodes hashable
[etc/neomutt.git] / .config / neomutt / buildmimetree.py
index 83cbe4d204beb515ae6018716b093c0e408ca794..97ada97a0fe1170686b634d9a25a1e28a89c8d40 100755 (executable)
@@ -6,8 +6,10 @@
 #
 # Configuration:
 #   neomuttrc (needs to be a single line):
 #
 # Configuration:
 #   neomuttrc (needs to be a single line):
+#     set my_mdwn_extensions="extra,admonition,codehilite,sane_lists,smarty"
 #     macro compose B "\
 #     macro compose B "\
-#       <enter-command> source '$my_confdir/buildmimetree.py setup|'<enter>\
+#       <enter-command> source '$my_confdir/buildmimetree.py \
+#       --tempdir $tempdir --extensions $my_mdwn_extensions|'<enter>\
 #       <enter-command> sourc e \$my_mdwn_postprocess_cmd_file<enter>\
 #     " "Convert message into a modern MIME tree with inline images"
 #
 #       <enter-command> sourc e \$my_mdwn_postprocess_cmd_file<enter>\
 #     " "Convert message into a modern MIME tree with inline images"
 #
@@ -21,8 +23,8 @@
 #   - python3-markdown
 # Optional:
 #   - pytest
 #   - python3-markdown
 # Optional:
 #   - pytest
-#   - Pynliner
-#   - Pygments, if installed, then syntax highlighting is enabled
+#   - Pynliner, provides --css-file and thus inline styling of HTML output
+#   - Pygments, then syntax highlighting for fenced code is enabled
 #
 # Latest version:
 #   https://git.madduck.net/etc/neomutt.git/blob_plain/HEAD:/.config/neomutt/buildmimetree.py
 #
 # Latest version:
 #   https://git.madduck.net/etc/neomutt.git/blob_plain/HEAD:/.config/neomutt/buildmimetree.py
@@ -36,7 +38,13 @@ import pathlib
 import markdown
 import tempfile
 import argparse
 import markdown
 import tempfile
 import argparse
-from collections import namedtuple
+import re
+import mimetypes
+from collections import namedtuple, OrderedDict
+from markdown.extensions import Extension
+from markdown.inlinepatterns import ImageInlineProcessor, IMAGE_LINK_RE
+from email.utils import make_msgid
+from urllib import request
 
 
 def parse_cli_args(*args, **kwargs):
 
 
 def parse_cli_args(*args, **kwargs):
@@ -47,59 +55,66 @@ def parse_cli_args(*args, **kwargs):
         )
     )
     parser.epilog = (
         )
     )
     parser.epilog = (
-        "Copyright © 2022 martin f. krafft <madduck@madduck.net>.\n"
+        "Copyright © 2023 martin f. krafft <madduck@madduck.net>.\n"
         "Released under the MIT licence"
     )
 
         "Released under the MIT licence"
     )
 
-    subp = parser.add_subparsers(help="Sub-command parsers", dest="mode")
-    parser_setup = subp.add_parser("setup", help="Setup phase")
-    parser_massage = subp.add_parser("massage", help="Massaging phase")
+    parser.add_argument(
+        "--extensions",
+        type=str,
+        default="",
+        help="Markdown extension to use (comma-separated list)",
+    )
 
 
-    parser_setup.add_argument(
-        "--debug-commands",
+    if _PYNLINER:
+        parser.add_argument(
+            "--css-file",
+            type=str,
+            default="",
+            help="CSS file to merge with the final HTML",
+        )
+    else:
+        parser.set_defaults(css_file=None)
+
+    parser.add_argument(
+        "--only-build",
         action="store_true",
         action="store_true",
-        help="Turn on debug logging of commands generated to stderr",
+        help="Only build, don't send the message",
     )
 
     )
 
-    parser_setup.add_argument(
-        "--extension",
-        "-x",
-        metavar="EXTENSION",
-        dest="extensions",
-        nargs="?",
-        default=[],
-        action="append",
-        help="Markdown extension to add to the list of extensions use",
+    parser.add_argument(
+        "--tempdir",
+        default=None,
+        help="Specify temporary directory to use for attachments",
     )
 
     )
 
-    parser_massage.add_argument(
+    parser.add_argument(
         "--debug-commands",
         action="store_true",
         help="Turn on debug logging of commands generated to stderr",
     )
 
         "--debug-commands",
         action="store_true",
         help="Turn on debug logging of commands generated to stderr",
     )
 
-    parser_massage.add_argument(
-        "--debug-walk",
-        action="store_true",
-        help="Turn on debugging to stderr of the MIME tree walk",
-    )
-
-    parser_massage.add_argument(
-        "--extensions",
-        metavar="EXTENSIONS",
-        type=str,
-        default="",
-        help="Markdown extension to use (comma-separated list)",
+    subp = parser.add_subparsers(help="Sub-command parsers", dest="mode")
+    massage_p = subp.add_parser(
+        "massage", help="Massaging phase (internal use)"
     )
 
     )
 
-    parser_massage.add_argument(
+    massage_p.add_argument(
         "--write-commands-to",
         "--write-commands-to",
+        "-o",
         metavar="PATH",
         dest="cmdpath",
         metavar="PATH",
         dest="cmdpath",
+        required=True,
         help="Temporary file path to write commands to",
     )
 
         help="Temporary file path to write commands to",
     )
 
-    parser_massage.add_argument(
+    massage_p.add_argument(
+        "--debug-walk",
+        action="store_true",
+        help="Turn on debugging to stderr of the MIME tree walk",
+    )
+
+    massage_p.add_argument(
         "MAILDRAFT",
         nargs="?",
         help="If provided, the script is invoked as editor on the mail draft",
         "MAILDRAFT",
         nargs="?",
         help="If provided, the script is invoked as editor on the mail draft",
@@ -108,6 +123,110 @@ def parse_cli_args(*args, **kwargs):
     return parser.parse_args(*args, **kwargs)
 
 
     return parser.parse_args(*args, **kwargs)
 
 
+# [ MARKDOWN WRAPPING ] #######################################################
+
+
+InlineImageInfo = namedtuple(
+    "InlineImageInfo", ["cid", "desc"], defaults=[None]
+)
+
+
+class InlineImageExtension(Extension):
+    class RelatedImageInlineProcessor(ImageInlineProcessor):
+        def __init__(self, re, md, ext):
+            super().__init__(re, md)
+            self._ext = ext
+
+        def handleMatch(self, m, data):
+            el, start, end = super().handleMatch(m, data)
+            if "src" in el.attrib:
+                src = el.attrib["src"]
+                if "://" not in src or src.startswith("file://"):
+                    # We only inline local content
+                    cid = self._ext.get_cid_for_image(el.attrib)
+                    el.attrib["src"] = f"cid:{cid}"
+            return el, start, end
+
+    def __init__(self):
+        super().__init__()
+        self._images = OrderedDict()
+
+    def extendMarkdown(self, md):
+        md.registerExtension(self)
+        inline_image_proc = self.RelatedImageInlineProcessor(
+            IMAGE_LINK_RE, md, self
+        )
+        md.inlinePatterns.register(inline_image_proc, "image_link", 150)
+
+    def get_cid_for_image(self, attrib):
+        msgid = make_msgid()[1:-1]
+        path = attrib["src"]
+        if path.startswith("/"):
+            path = f"file://{path}"
+        self._images[path] = InlineImageInfo(
+            msgid, attrib.get("title", attrib.get("alt"))
+        )
+        return msgid
+
+    def get_images(self):
+        return self._images
+
+
+def markdown_with_inline_image_support(
+    text, *, extensions=None, extension_configs=None
+):
+    inline_image_handler = InlineImageExtension()
+    extensions = extensions or []
+    extensions.append(inline_image_handler)
+    mdwn = markdown.Markdown(
+        extensions=extensions, extension_configs=extension_configs
+    )
+    htmltext = mdwn.convert(text)
+
+    images = inline_image_handler.get_images()
+
+    def replace_image_with_cid(matchobj):
+        for m in (matchobj.group(1), f"file://{matchobj.group(1)}"):
+            if m in images:
+                return f"(cid:{images[m].cid}"
+        return matchobj.group(0)
+
+    text = re.sub(r"\(([^)\s]+)", replace_image_with_cid, text)
+    return text, htmltext, images
+
+
+# [ CSS STYLING ] #############################################################
+
+try:
+    import pynliner
+
+    _PYNLINER = True
+
+except ImportError:
+    _PYNLINER = False
+
+try:
+    from pygments.formatters import get_formatter_by_name
+
+    _CODEHILITE_CLASS = "codehilite"
+
+    _PYGMENTS_CSS = get_formatter_by_name(
+        "html", style="default"
+    ).get_style_defs(f".{_CODEHILITE_CLASS}")
+
+except ImportError:
+    _PYGMENTS_CSS = None
+
+
+def apply_styling(html, css):
+    return (
+        pynliner.Pynliner()
+        .from_string(html)
+        .with_cssString("\n".join(s for s in [_PYGMENTS_CSS, css] if s))
+        .run()
+    )
+
+
 # [ PARTS GENERATION ] ########################################################
 
 
 # [ PARTS GENERATION ] ########################################################
 
 
@@ -133,47 +252,86 @@ class Multipart(
     def __str__(self):
         return f"<multipart/{self.subtype}> children={len(self.children)}"
 
     def __str__(self):
         return f"<multipart/{self.subtype}> children={len(self.children)}"
 
+    def __hash__(self):
+        return hash(str(self.subtype) + "".join(str(self.children)))
+
+
+def filewriter_fn(path, content, mode="w", **kwargs):
+    with open(path, mode, **kwargs) as out_f:
+        out_f.write(content)
+
+
+def collect_inline_images(
+    images, *, tempdir=None, filewriter_fn=filewriter_fn
+):
+    relparts = []
+    for path, info in images.items():
+        data = request.urlopen(path)
+
+        mimetype = data.headers["Content-Type"]
+        ext = mimetypes.guess_extension(mimetype)
+        tempfilename = tempfile.mkstemp(prefix="img", suffix=ext, dir=tempdir)
+        path = pathlib.Path(tempfilename[1])
+
+        filewriter_fn(path, data.read(), "w+b")
+
+        relparts.append(
+            Part(
+                *mimetype.split("/"),
+                path,
+                cid=info.cid,
+                desc=f"Image: {info.desc}",
+            )
+        )
+
+    return relparts
+
 
 
-def convert_markdown_to_html(maildraft, *, extensions=None):
-    draftpath = pathlib.Path(maildraft)
+def convert_markdown_to_html(
+    origtext,
+    draftpath,
+    *,
+    cssfile=None,
+    filewriter_fn=filewriter_fn,
+    tempdir=None,
+    extensions=None,
+    extension_configs=None,
+):
+    # TODO extension_configs need to be handled differently
+    extension_configs = extension_configs or {}
+    extension_configs.setdefault("pymdownx.highlight", {})
+    extension_configs["pymdownx.highlight"]["css_class"] = _CODEHILITE_CLASS
+
+    origtext, htmltext, images = markdown_with_inline_image_support(
+        origtext, extensions=extensions, extension_configs=extension_configs
+    )
+
+    filewriter_fn(draftpath, origtext, encoding="utf-8")
     textpart = Part(
         "text", "plain", draftpath, "Plain-text version", orig=True
     )
 
     textpart = Part(
         "text", "plain", draftpath, "Plain-text version", orig=True
     )
 
-    with open(draftpath, "r", encoding="utf-8") as textmarkdown:
-        text = textmarkdown.read()
-
-    mdwn = markdown.Markdown(extensions=extensions)
-    html = mdwn.convert(text)
+    htmltext = apply_styling(htmltext, cssfile)
 
     htmlpath = draftpath.with_suffix(".html")
 
     htmlpath = draftpath.with_suffix(".html")
+    filewriter_fn(
+        htmlpath, htmltext, encoding="utf-8", errors="xmlcharrefreplace"
+    )
     htmlpart = Part("text", "html", htmlpath, "HTML version")
 
     htmlpart = Part("text", "html", htmlpath, "HTML version")
 
-    with open(
-        htmlpath, "w", encoding="utf-8", errors="xmlcharrefreplace"
-    ) as texthtml:
-        texthtml.write(html)
-
-    logopart = Part(
-        "image",
-        "png",
-        "/usr/share/doc/neomutt/logo/neomutt-256.png",
-        "Logo",
-        "neomutt-256.png",
+    altpart = Multipart(
+        "alternative", [textpart, htmlpart], "Group of alternative content"
     )
 
     )
 
-    return Multipart(
-        "relative",
-        [
-            Multipart(
-                "alternative",
-                [textpart, htmlpart],
-                "Group of alternative content",
-            ),
-            logopart,
-        ],
-        "Group of related content",
+    imgparts = collect_inline_images(
+        images, tempdir=tempdir, filewriter_fn=filewriter_fn
     )
     )
+    if imgparts:
+        return Multipart(
+            "relative", [altpart] + imgparts, "Group of related content"
+        )
+    else:
+        return altpart
 
 
 class MIMETreeDFWalker:
 
 
 class MIMETreeDFWalker:
@@ -282,17 +440,18 @@ class MuttCommands:
 
 
 def do_setup(
 
 
 def do_setup(
-    extensions=None, *, out_f=sys.stdout, temppath=None, debug_commands=False
+    *,
+    out_f=sys.stdout,
+    temppath=None,
+    tempdir=None,
+    debug_commands=False,
 ):
 ):
-    extensions = extensions or []
     temppath = temppath or pathlib.Path(
     temppath = temppath or pathlib.Path(
-        tempfile.mkstemp(prefix="muttmdwn-")[1]
+        tempfile.mkstemp(prefix="muttmdwn-", dir=tempdir)[1]
     )
     cmds = MuttCommands(out_f, debug=debug_commands)
 
     )
     cmds = MuttCommands(out_f, debug=debug_commands)
 
-    editor = f"{sys.argv[0]} massage --write-commands-to {temppath}"
-    if extensions:
-        editor = f'{editor} --extensions {",".join(extensions)}'
+    editor = f"{' '.join(sys.argv)} massage --write-commands-to {temppath}"
 
     cmds.cmd('set my_editor="$editor"')
     cmds.cmd('set my_edit_headers="$edit_headers"')
 
     cmds.cmd('set my_editor="$editor"')
     cmds.cmd('set my_edit_headers="$edit_headers"')
@@ -304,11 +463,15 @@ def do_setup(
 
 
 def do_massage(
 
 
 def do_massage(
-    maildraft,
+    draft_f,
+    draftpath,
     cmd_f,
     *,
     extensions=None,
     cmd_f,
     *,
     extensions=None,
+    cssfile=None,
     converter=convert_markdown_to_html,
     converter=convert_markdown_to_html,
+    only_build=False,
+    tempdir=None,
     debug_commands=False,
     debug_walk=False,
 ):
     debug_commands=False,
     debug_walk=False,
 ):
@@ -331,7 +494,13 @@ def do_massage(
     cmds.flush()
 
     extensions = extensions.split(",") if extensions else []
     cmds.flush()
 
     extensions = extensions.split(",") if extensions else []
-    tree = converter(maildraft, extensions=extensions)
+    tree = converter(
+        draft_f.read(),
+        draftpath,
+        cssfile=cssfile,
+        tempdir=tempdir,
+        extensions=extensions,
+    )
 
     mimetree = MIMETreeDFWalker(debug=debug_walk)
 
 
     mimetree = MIMETreeDFWalker(debug=debug_walk)
 
@@ -341,23 +510,29 @@ def do_massage(
         depth-first, and responsible for telling NeoMutt how to assemble
         the tree.
         """
         depth-first, and responsible for telling NeoMutt how to assemble
         the tree.
         """
+        KILL_LINE = r"\Ca\Ck"
+
         if isinstance(item, Part):
             # We've hit a leaf-node, i.e. an alternative or a related part
             # with actual content.
 
         if isinstance(item, Part):
             # We've hit a leaf-node, i.e. an alternative or a related part
             # with actual content.
 
-            # If the part is not an original part, i.e. doesn't already
-            # exist, we must first add it.
-            if not item.orig:
+            # Let's add the part
+            if item.orig:
+                # The original source already exists in the NeoMutt tree, but
+                # the underlying file may have been modified, so we need to
+                # update the encoding, but that's it:
+                cmds.push("<update-encoding>")
+            else:
+                # … whereas all other parts need to be added, and they're all
+                # considered to be temporary and inline:
                 cmds.push(f"<attach-file>{item.path}<enter>")
                 cmds.push("<toggle-unlink><toggle-disposition>")
                 cmds.push(f"<attach-file>{item.path}<enter>")
                 cmds.push("<toggle-unlink><toggle-disposition>")
-                if item.cid:
-                    cmds.push(f"<edit-content-id>\\Ca\\Ck{item.cid}<enter>")
 
 
-            # If the item (including the original) comes with a
-            # description, then we might just as well update the NeoMutt
+            # If the item (including the original) comes with additional
+            # information, then we might just as well update the NeoMutt
             # tree now:
             # tree now:
-            if item.desc:
-                cmds.push(f"<edit-description>\\Ca\\Ck{item.desc}<enter>")
+            if item.cid:
+                cmds.push(f"<edit-content-id>{KILL_LINE}{item.cid}<enter>")
 
         elif isinstance(item, Multipart):
             # This node has children, but we already visited them (see
 
         elif isinstance(item, Multipart):
             # This node has children, but we already visited them (see
@@ -366,19 +541,19 @@ def do_massage(
             # appropriate grouping:
             if item.subtype == "alternative":
                 cmds.push("<group-alternatives>")
             # appropriate grouping:
             if item.subtype == "alternative":
                 cmds.push("<group-alternatives>")
-            elif item.subtype == "relative":
+            elif item.subtype in ("relative", "related"):
                 cmds.push("<group-related>")
             elif item.subtype == "multilingual":
                 cmds.push("<group-multilingual>")
 
                 cmds.push("<group-related>")
             elif item.subtype == "multilingual":
                 cmds.push("<group-multilingual>")
 
-            # Again, if there is a description, we might just as well:
-            if item.desc:
-                cmds.push(f"<edit-description>\\Ca\\Ck{item.desc}<enter>")
-
         else:
             # We should never get here
             assert not "is valid part"
 
         else:
             # We should never get here
             assert not "is valid part"
 
+        # If the item has a description, we might just as well add it
+        if item.desc:
+            cmds.push(f"<edit-description>{KILL_LINE}{item.desc}<enter>")
+
         # Finally, if we're at non-root level, tag the new container,
         # as it might itself be part of a container, to be processed
         # one level up:
         # Finally, if we're at non-root level, tag the new container,
         # as it might itself be part of a container, to be processed
         # one level up:
@@ -392,6 +567,9 @@ def do_massage(
     # function
     mimetree.walk(tree, visitor_fn=visitor_fn)
 
     # function
     mimetree.walk(tree, visitor_fn=visitor_fn)
 
+    if not only_build:
+        cmds.push("<send-message>")
+
     # Finally, cleanup. Since we're responsible for removing the temporary
     # file, how's this for a little hack?
     try:
     # Finally, cleanup. Since we're responsible for removing the temporary
     # file, how's this for a little hack?
     try:
@@ -408,15 +586,24 @@ def do_massage(
 if __name__ == "__main__":
     args = parse_cli_args()
 
 if __name__ == "__main__":
     args = parse_cli_args()
 
-    if args.mode == "setup":
-        do_setup(args.extensions, debug_commands=args.debug_commands)
+    if args.mode is None:
+        do_setup(
+            tempdir=args.tempdir,
+            debug_commands=args.debug_commands,
+        )
 
     elif args.mode == "massage":
 
     elif args.mode == "massage":
-        with open(args.cmdpath, "w") as cmd_f:
+        with open(args.MAILDRAFT, "r") as draft_f, open(
+            args.cmdpath, "w"
+        ) as cmd_f:
             do_massage(
             do_massage(
-                args.MAILDRAFT,
+                draft_f,
+                pathlib.Path(args.MAILDRAFT),
                 cmd_f,
                 extensions=args.extensions,
                 cmd_f,
                 extensions=args.extensions,
+                cssfile=args.css_file,
+                only_build=args.only_build,
+                tempdir=args.tempdir,
                 debug_commands=args.debug_commands,
                 debug_walk=args.debug_walk,
             )
                 debug_commands=args.debug_commands,
                 debug_walk=args.debug_walk,
             )
@@ -426,6 +613,7 @@ if __name__ == "__main__":
 
 try:
     import pytest
 
 try:
     import pytest
+    from io import StringIO
 
     class Tests:
         @pytest.fixture
 
     class Tests:
         @pytest.fixture
@@ -490,7 +678,13 @@ try:
                     Multipart(
                         "alternative",
                         children=[
                     Multipart(
                         "alternative",
                         children=[
-                            Part("text", "plain", "part.txt", desc="Plain"),
+                            Part(
+                                "text",
+                                "plain",
+                                "part.txt",
+                                desc="Plain",
+                                orig=True,
+                            ),
                             Part("text", "html", "part.html", desc="HTML"),
                         ],
                         desc="Alternative",
                             Part("text", "html", "part.html", desc="HTML"),
                         ],
                         desc="Alternative",
@@ -525,7 +719,6 @@ try:
 
         def test_MIMETreeDFWalker_list_to_mixed(self, basic_mime_tree):
             mimetree = MIMETreeDFWalker()
 
         def test_MIMETreeDFWalker_list_to_mixed(self, basic_mime_tree):
             mimetree = MIMETreeDFWalker()
-
             items = []
 
             def visitor_fn(item, stack, debugprint):
             items = []
 
             def visitor_fn(item, stack, debugprint):
@@ -546,26 +739,247 @@ try:
             mimetree.walk(basic_mime_tree)
             assert len(items) == 5
 
             mimetree.walk(basic_mime_tree)
             assert len(items) == 5
 
-        def test_do_setup_no_extensions(self, const1, capsys):
-            "Assert basics about the setup command output"
-            do_setup(temppath=const1, out_f=sys.stdout)
-            captout = capsys.readouterr()
-            lines = captout.out.splitlines()
-            assert lines[2].endswith(f'{const1}"')
-            assert lines[4].endswith(const1)
-            assert "first-entry" in lines[-1]
-            assert "edit-file" in lines[-1]
-
-        def test_do_setup_extensions(self, const1, const2, capsys):
-            "Assert that extensions are passed to editor"
-            do_setup(
-                temppath=const1, extensions=[const2, const1], out_f=sys.stdout
+        @pytest.fixture
+        def string_io(self, const1, text=None):
+            return StringIO(text or const1)
+
+        def test_do_massage_basic(self, const1, string_io, capsys):
+            def converter(drafttext, draftpath, cssfile, extensions, tempdir):
+                return Part("text", "plain", draftpath, orig=True)
+
+            do_massage(
+                draft_f=string_io,
+                draftpath=const1,
+                cmd_f=sys.stdout,
+                converter=converter,
             )
             )
-            captout = capsys.readouterr()
-            lines = captout.out.splitlines()
-            # assert comma-separated list of extensions passed
-            assert lines[2].endswith(f'{const2},{const1}"')
-            assert lines[4].endswith(const1)
+
+            captured = capsys.readouterr()
+            lines = captured.out.splitlines()
+            assert '="$my_editor"' in lines.pop(0)
+            assert '="$my_edit_headers"' in lines.pop(0)
+            assert "unset my_editor" == lines.pop(0)
+            assert "unset my_edit_headers" == lines.pop(0)
+            assert "send-message" in lines.pop(0)
+            assert "update-encoding" in lines.pop(0)
+            assert "source 'rm -f " in lines.pop(0)
+            assert "unset my_mdwn_postprocess_cmd_file" == lines.pop(0)
+
+        def test_do_massage_fulltree(
+            self, string_io, const1, basic_mime_tree, capsys
+        ):
+            def converter(drafttext, draftpath, cssfile, extensions, tempdir):
+                return basic_mime_tree
+
+            do_massage(
+                draft_f=string_io,
+                draftpath=const1,
+                cmd_f=sys.stdout,
+                converter=converter,
+            )
+
+            captured = capsys.readouterr()
+            lines = captured.out.splitlines()[4:]
+            assert "send-message" in lines.pop(0)
+            assert "Related" in lines.pop(0)
+            assert "group-related" in lines.pop(0)
+            assert "tag-entry" in lines.pop(0)
+            assert "Logo" in lines.pop(0)
+            assert "content-id" in lines.pop(0)
+            assert "toggle-unlink" in lines.pop(0)
+            assert "logo.png" in lines.pop(0)
+            assert "tag-entry" in lines.pop(0)
+            assert "Alternative" in lines.pop(0)
+            assert "group-alternatives" in lines.pop(0)
+            assert "tag-entry" in lines.pop(0)
+            assert "HTML" in lines.pop(0)
+            assert "toggle-unlink" in lines.pop(0)
+            assert "part.html" in lines.pop(0)
+            assert "tag-entry" in lines.pop(0)
+            assert "Plain" in lines.pop(0)
+            assert "update-encoding" in lines.pop(0)
+            assert len(lines) == 2
+
+        @pytest.fixture
+        def fake_filewriter(self):
+            class FileWriter:
+                def __init__(self):
+                    self._writes = []
+
+                def __call__(self, path, content, mode="w", **kwargs):
+                    self._writes.append((path, content))
+
+                def pop(self, index=-1):
+                    return self._writes.pop(index)
+
+            return FileWriter()
+
+        @pytest.fixture
+        def markdown_non_converter(self, const1, const2):
+            return lambda s, text: f"{const1}{text}{const2}"
+
+        def test_converter_tree_basic(
+            self, const1, const2, fake_filewriter, markdown_non_converter
+        ):
+            path = pathlib.Path(const2)
+            tree = convert_markdown_to_html(
+                const1, path, filewriter_fn=fake_filewriter
+            )
+
+            assert tree.subtype == "alternative"
+            assert len(tree.children) == 2
+            assert tree.children[0].subtype == "plain"
+            assert tree.children[0].path == path
+            assert tree.children[0].orig
+            assert tree.children[1].subtype == "html"
+            assert tree.children[1].path == path.with_suffix(".html")
+
+        def test_converter_writes(
+            self,
+            const1,
+            const2,
+            fake_filewriter,
+            monkeypatch,
+            markdown_non_converter,
+        ):
+            path = pathlib.Path(const2)
+
+            with monkeypatch.context() as m:
+                m.setattr(markdown.Markdown, "convert", markdown_non_converter)
+                convert_markdown_to_html(
+                    const1, path, filewriter_fn=fake_filewriter
+                )
+
+            assert (path, const1) == fake_filewriter.pop(0)
+            assert (
+                path.with_suffix(".html"),
+                markdown_non_converter(None, const1),
+            ) == fake_filewriter.pop(0)
+
+        def test_markdown_inline_image_processor(self):
+            imgpath1 = "file:/path/to/image.png"
+            imgpath2 = "file:///path/to/image.png?url=params"
+            imgpath3 = "/path/to/image.png"
+            text = f"""![inline local image]({imgpath1})
+                       ![image inlined
+                         with newline]({imgpath2})
+                       ![image local path]({imgpath3})"""
+            text, html, images = markdown_with_inline_image_support(text)
+
+            # local paths have been normalised to URLs:
+            imgpath3 = f"file://{imgpath3}"
+
+            assert 'src="cid:' in html
+            assert "](cid:" in text
+            assert len(images) == 3
+            assert imgpath1 in images
+            assert imgpath2 in images
+            assert imgpath3 in images
+            assert images[imgpath1].cid != images[imgpath2].cid
+            assert images[imgpath1].cid != images[imgpath3].cid
+            assert images[imgpath2].cid != images[imgpath3].cid
+
+        def test_markdown_inline_image_processor_title_to_desc(self, const1):
+            imgpath = "file:///path/to/image.png"
+            text = f'![inline local image]({imgpath} "{const1}")'
+            text, html, images = markdown_with_inline_image_support(text)
+            assert images[imgpath].desc == const1
+
+        def test_markdown_inline_image_processor_alt_to_desc(self, const1):
+            imgpath = "file:///path/to/image.png"
+            text = f"![{const1}]({imgpath})"
+            text, html, images = markdown_with_inline_image_support(text)
+            assert images[imgpath].desc == const1
+
+        def test_markdown_inline_image_processor_title_over_alt_desc(
+            self, const1, const2
+        ):
+            imgpath = "file:///path/to/image.png"
+            text = f'![{const1}]({imgpath} "{const2}")'
+            text, html, images = markdown_with_inline_image_support(text)
+            assert images[imgpath].desc == const2
+
+        def test_markdown_inline_image_not_external(self):
+            imgpath = "https://path/to/image.png"
+            text = f"![inline image]({imgpath})"
+            text, html, images = markdown_with_inline_image_support(text)
+
+            assert 'src="cid:' not in html
+            assert "](cid:" not in text
+            assert len(images) == 0
+
+        def test_markdown_inline_image_local_file(self):
+            imgpath = "/path/to/image.png"
+            text = f"![inline image]({imgpath})"
+            text, html, images = markdown_with_inline_image_support(text)
+
+            for k, v in images.items():
+                assert k == f"file://{imgpath}"
+                break
+
+        @pytest.fixture
+        def test_png(self):
+            return (
+                "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAE"
+                "AAAABCAAAAAA6fptVAAAACklEQVQI12P4DwABAQEAG7buVgAA"
+            )
+
+        def test_markdown_inline_image_processor_base64(self, test_png):
+            text = f"![1px white inlined]({test_png})"
+            text, html, images = markdown_with_inline_image_support(text)
+
+            assert 'src="cid:' in html
+            assert "](cid:" in text
+            assert len(images) == 1
+            assert test_png in images
+
+        def test_converter_tree_inline_image_base64(
+            self, test_png, const1, fake_filewriter
+        ):
+            text = f"![inline base64 image]({test_png})"
+            path = pathlib.Path(const1)
+            tree = convert_markdown_to_html(
+                text, path, filewriter_fn=fake_filewriter
+            )
+
+            assert tree.subtype == "relative"
+            assert tree.children[1].subtype == "png"
+            written = fake_filewriter.pop()
+            assert tree.children[1].path == written[0]
+            assert written[1] == request.urlopen(test_png).read()
+
+        def test_inline_image_collection(
+            self, test_png, const1, const2, fake_filewriter
+        ):
+            test_images = {test_png: InlineImageInfo(cid=const1, desc=const2)}
+            relparts = collect_inline_images(
+                test_images, filewriter_fn=fake_filewriter
+            )
+
+            written = fake_filewriter.pop()
+            assert b"PNG" in written[1]
+
+            assert relparts[0].subtype == "png"
+            assert relparts[0].path == written[0]
+            assert relparts[0].cid == const1
+            assert relparts[0].desc.endswith(const2)
+
+        def test_apply_stylesheet(self):
+            if _PYNLINER:
+                html = "<p>Hello, world!</p>"
+                css = "p { color:red }"
+                out = apply_styling(html, css)
+                assert 'p style="color' in out
+
+        def test_apply_stylesheet_pygments(self):
+            if _PYGMENTS_CSS:
+                html = (
+                    f'<div class="{_CODEHILITE_CLASS}">'
+                    "<pre>def foo():\n    return</pre></div>"
+                )
+                out = apply_styling(html, _PYGMENTS_CSS)
+                assert f'{_CODEHILITE_CLASS}" style="' in out
+
 
 except ImportError:
     pass
 
 except ImportError:
     pass