]> 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:

fix attribution and enable hooks
[etc/neomutt.git] / .config / neomutt / buildmimetree.py
index a0112c80c5ddd4dc816425978abec31f25ba8753..32fc17c005b613055a3dc42fdb8f744f148652e4 100755 (executable)
@@ -6,8 +6,11 @@
 #
 # 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 --tempdir $tempdir|'<enter>\
+#       <enter-command> source '$my_confdir/buildmimetree.py \
+#       --tempdir $tempdir --extensions $my_mdwn_extensions \
+#       --css-file $my_confdir/htmlmail.css |'<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"
 #
 # Requirements:
 #   - python3
 #   - python3-markdown
 # Requirements:
 #   - python3
 #   - python3-markdown
+#   - python3-beautifulsoup4
 # Optional:
 #   - pytest
 # 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
 #
 
 import sys
 #
 
 import sys
+import os.path
 import pathlib
 import markdown
 import tempfile
 import argparse
 import re
 import mimetypes
 import pathlib
 import markdown
 import tempfile
 import argparse
 import re
 import mimetypes
+import bs4
+import xml.etree.ElementTree as etree
+import io
 from collections import namedtuple, OrderedDict
 from markdown.extensions import Extension
 from collections import namedtuple, OrderedDict
 from markdown.extensions import Extension
+from markdown.blockprocessors import BlockProcessor
 from markdown.inlinepatterns import ImageInlineProcessor, IMAGE_LINK_RE
 from email.utils import make_msgid
 from urllib import request
 from markdown.inlinepatterns import ImageInlineProcessor, IMAGE_LINK_RE
 from email.utils import make_msgid
 from urllib import request
@@ -53,86 +62,269 @@ 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",
+        metavar="EXT[,EXT[,EXT]]",
+        type=str,
+        default="",
+        help="Markdown extension to use (comma-separated list)",
+    )
 
 
-    parser_setup.add_argument(
-        "--debug-commands",
+    if _PYNLINER:
+        parser.add_argument(
+            "--css-file",
+            metavar="FILE",
+            type=pathlib.Path,
+            default=os.devnull,
+            help="CSS file to merge with the final HTML",
+        )
+    else:
+        parser.set_defaults(css_file=None)
+
+    parser.add_argument(
+        "--related-to-html-only",
         action="store_true",
         action="store_true",
-        help="Turn on debug logging of commands generated to stderr",
+        help="Make related content be sibling to HTML parts only",
     )
 
     )
 
-    parser_setup.add_argument(
-        "--tempdir",
-        default=None,
-        help="Specify temporary directory to use for attachments",
-    )
+    def positive_integer(value):
+        try:
+            if int(value) > 0:
+                return int(value)
 
 
-    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",
+        except ValueError:
+            pass
+
+        raise ValueError("Must be a positive integer")
+
+    parser.add_argument(
+        "--max-number-other-attachments",
+        metavar="INTEGER",
+        type=positive_integer,
+        default=20,
+        help="Maximum number of other attachments to expect",
     )
 
     )
 
-    parser_setup.add_argument(
-        "--send-message",
+    parser.add_argument(
+        "--only-build",
+        "--just-build",
         action="store_true",
         action="store_true",
-        help="Generate command(s) to send the message after processing",
+        help="Only build, don't send the message",
+    )
+
+    parser.add_argument(
+        "--tempdir",
+        metavar="DIR",
+        type=pathlib.Path,
+        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(
+    parser.add_argument(
         "--debug-walk",
         action="store_true",
         help="Turn on debugging to stderr of the MIME tree walk",
     )
 
         "--debug-walk",
         action="store_true",
         help="Turn on debugging to stderr of the MIME tree walk",
     )
 
-    parser_massage.add_argument(
-        "--tempdir",
-        default=None,
-        help="Specify temporary directory to use for attachments",
+    parser.add_argument(
+        "--dump-html",
+        metavar="FILE",
+        type=pathlib.Path,
+        help="Write the generated HTML to the file",
     )
 
     )
 
-    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",
-        metavar="PATH",
+        "-o",
+        metavar="FILE",
         dest="cmdpath",
         dest="cmdpath",
+        type=pathlib.Path,
+        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(
         "MAILDRAFT",
         nargs="?",
         "MAILDRAFT",
         nargs="?",
+        type=pathlib.Path,
         help="If provided, the script is invoked as editor on the mail draft",
     )
 
     return parser.parse_args(*args, **kwargs)
 
 
         help="If provided, the script is invoked as editor on the mail draft",
     )
 
     return parser.parse_args(*args, **kwargs)
 
 
-# [ MARKDOWN WRAPPING ] #######################################################
+# [ FILE I/O HANDLING ] #######################################################
+
+
+class File:
+    def __init__(self, path=None, mode="r", content=None, **kwargs):
+        if path:
+            if content:
+                raise RuntimeError("Cannot specify path and content for File")
+
+            self._path = (
+                path if isinstance(path, pathlib.Path) else pathlib.Path(path)
+            )
+        else:
+            self._path = None
+
+        if content and not re.search(r"[r+]", mode):
+            raise RuntimeError("Cannot specify content without read mode")
+
+        self._rcache = [content] if content else []
+        self._wcache = []
+        self._mode = mode
+        self._kwargs = kwargs
+        self._file = None
+
+    def open(self):
+        if self._path:
+            self._file = open(self._path, self._mode, **self._kwargs)
+        elif "b" in self._mode:
+            self._file = io.BytesIO()
+        else:
+            self._file = io.StringIO()
+
+    def __enter__(self):
+        self.open()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.close()
+
+    def close(self):
+        self._file.close()
+        self._file = None
+        self._rcache = self._wcache
+
+    def _get_rcache(self):
+        return (b"" if "b" in self._mode else "").join(self._rcache)
+
+    def _get_wcache(self):
+        return (b"" if "b" in self._mode else "").join(self._wcache)
+
+    def _add_to_rcache(self, s):
+        self._rcache.append(s)
+
+    def _add_to_wcache(self, s):
+        self._wcache.append(s)
+
+    def read(self, *, cache=True):
+        if cache and self._rcache:
+            return self._get_rcache()
+
+        if not self._file:
+            with self as f:
+                return f.read(cache=cache)
+
+        self._file.seek(0)
+        if cache:
+            self._add_to_rcache(self._file.read())
+            return self._get_rcache()
+        else:
+            return self._file.read()
+
+    def write(self, s, *, cache=True):
+        if not self._file:
+            with self as f:
+                return f.write(s, cache=cache)
+
+        self._file.seek(0)
+        self._rcache = self._wcache
+
+        if cache:
+            self._add_to_wcache(s)
+
+        written = self._file.write(s)
+        self._file.flush()
+        return written
+
+    path = property(lambda s: s._path)
+
+    def __repr__(self):
+        return (
+            f'<File path={self._path or "(buffered)"} open={bool(self._file)} '
+            f"rcache={sum(len(c) for c in self._rcache) if self._rcache is not None else False} "
+            f"wcache={sum(len(c) for c in self._wcache) if self._wcache is not None else False}>"
+        )
+
+
+class FileFactory:
+    def __init__(self):
+        self._files = []
+
+    def __call__(self, path=None, mode="r", content=None, **kwargs):
+        f = File(path, mode, content, **kwargs)
+        self._files.append(f)
+        return f
+
+    def __len__(self):
+        return self._files.__len__()
+
+    def pop(self, idx=-1):
+        return self._files.pop(idx)
+
+    def __getitem__(self, idx):
+        return self._files.__getitem__(idx)
+
+    def __contains__(self, f):
+        return self._files.__contains__(f)
+
+
+class FakeFileFactory(FileFactory):
+    def __init__(self):
+        super().__init__()
+        self._paths2files = OrderedDict()
+
+    def __call__(self, path=None, mode="r", content=None, **kwargs):
+        if path in self._paths2files:
+            return self._paths2files[path]
+
+        f = super().__call__(None, mode, content, **kwargs)
+        self._paths2files[path] = f
+
+        mypath = path
+
+        class FakeFile(File):
+            path = mypath
+
+        # this is quality Python! We do this so that the fake file, which has
+        # no path, fake-pretends to have a path for testing purposes.
+
+        f.__class__ = FakeFile
+        return f
+
+    def __getitem__(self, path):
+        return self._paths2files.__getitem__(path)
+
+    def get(self, path, default):
+        return self._paths2files.get(path, default)
+
+    def pop(self, last=True):
+        return self._paths2files.popitem(last)
+
+    def __repr__(self):
+        return (
+            f"<FakeFileFactory nfiles={len(self._files)} "
+            f"paths={len(self._paths2files)}>"
+        )
+
+
+# [ IMAGE HANDLING ] ##########################################################
 
 
 InlineImageInfo = namedtuple(
 
 
 InlineImageInfo = namedtuple(
@@ -140,11 +332,43 @@ InlineImageInfo = namedtuple(
 )
 
 
 )
 
 
+class ImageRegistry:
+    def __init__(self):
+        self._images = OrderedDict()
+
+    def register(self, path, description=None):
+        # path = str(pathlib.Path(path).expanduser())
+        path = os.path.expanduser(path)
+        if path.startswith("/"):
+            path = f"file://{path}"
+        cid = make_msgid()[1:-1]
+        self._images[path] = InlineImageInfo(cid, description)
+        return cid
+
+    def __iter__(self):
+        return self._images.__iter__()
+
+    def __getitem__(self, idx):
+        return self._images.__getitem__(idx)
+
+    def __len__(self):
+        return self._images.__len__()
+
+    def items(self):
+        return self._images.items()
+
+    def __repr__(self):
+        return f"<ImageRegistry(items={len(self._images)})>"
+
+    def __str__(self):
+        return self._images.__str__()
+
+
 class InlineImageExtension(Extension):
     class RelatedImageInlineProcessor(ImageInlineProcessor):
 class InlineImageExtension(Extension):
     class RelatedImageInlineProcessor(ImageInlineProcessor):
-        def __init__(self, re, md, ext):
+        def __init__(self, re, md, registry):
             super().__init__(re, md)
             super().__init__(re, md)
-            self._ext = ext
+            self._registry = registry
 
         def handleMatch(self, m, data):
             el, start, end = super().handleMatch(m, data)
 
         def handleMatch(self, m, data):
             el, start, end = super().handleMatch(m, data)
@@ -152,52 +376,152 @@ class InlineImageExtension(Extension):
                 src = el.attrib["src"]
                 if "://" not in src or src.startswith("file://"):
                     # We only inline local content
                 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)
+                    cid = self._registry.register(
+                        el.attrib["src"],
+                        el.attrib.get("title", el.attrib.get("alt")),
+                    )
                     el.attrib["src"] = f"cid:{cid}"
             return el, start, end
 
                     el.attrib["src"] = f"cid:{cid}"
             return el, start, end
 
-    def __init__(self):
+    def __init__(self, registry):
         super().__init__()
         super().__init__()
-        self._images = OrderedDict()
+        self._image_registry = registry
+
+    INLINE_PATTERN_NAME = "image_link"
 
     def extendMarkdown(self, md):
         md.registerExtension(self)
         inline_image_proc = self.RelatedImageInlineProcessor(
 
     def extendMarkdown(self, md):
         md.registerExtension(self)
         inline_image_proc = self.RelatedImageInlineProcessor(
-            IMAGE_LINK_RE, md, self
+            IMAGE_LINK_RE, md, self._image_registry
         )
         )
-        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"))
+        md.inlinePatterns.register(
+            inline_image_proc, InlineImageExtension.INLINE_PATTERN_NAME, 150
         )
         )
-        return msgid
 
 
-    def get_images(self):
-        return self._images
 
 
-
-def markdown_with_inline_image_support(text, *, extensions=None):
-    inline_image_handler = InlineImageExtension()
+def markdown_with_inline_image_support(
+    text,
+    *,
+    mdwn=None,
+    image_registry=None,
+    extensions=None,
+    extension_configs=None,
+):
+    registry = (
+        image_registry if image_registry is not None else ImageRegistry()
+    )
+    inline_image_handler = InlineImageExtension(registry=registry)
     extensions = extensions or []
     extensions.append(inline_image_handler)
     extensions = extensions or []
     extensions.append(inline_image_handler)
-    mdwn = markdown.Markdown(extensions=extensions)
-    htmltext = mdwn.convert(text)
+    mdwn = markdown.Markdown(
+        extensions=extensions, extension_configs=extension_configs
+    )
 
 
-    images = inline_image_handler.get_images()
+    htmltext = mdwn.convert(text)
 
     def replace_image_with_cid(matchobj):
         for m in (matchobj.group(1), f"file://{matchobj.group(1)}"):
 
     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}"
+            if m in registry:
+                return f"(cid:{registry[m].cid}"
         return matchobj.group(0)
 
     text = re.sub(r"\(([^)\s]+)", replace_image_with_cid, text)
         return matchobj.group(0)
 
     text = re.sub(r"\(([^)\s]+)", replace_image_with_cid, text)
-    return text, htmltext, images
+    return text, htmltext, registry, mdwn
+
+
+# [ 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()
+    )
+
+
+# [ QUOTE HANDLING ] ##########################################################
+
+
+class QuoteToAdmonitionExtension(Extension):
+    class EmailQuoteBlockProcessor(BlockProcessor):
+        RE = re.compile(r"(?:^|\n)>\s*(.*)")
+
+        def __init__(self, parser):
+            super().__init__(parser)
+            self._title = None
+
+        def test(self, parent, blocks):
+            if markdown.util.nearing_recursion_limit():
+                return False
+
+            lines = blocks.splitlines()
+            if len(lines) < 2:
+                if not self._title:
+                    return False
+
+                elif not self.RE.search(lines[0]):
+                    return False
+
+                return len(lines) > 0
+
+            elif not self.RE.search(lines[0]) and self.RE.search(lines[1]):
+                return True
+
+            elif self._title and self.RE.search(lines[1]):
+                return True
+
+            return False
+
+        def run(self, parent, blocks):
+            quotelines = blocks.pop(0).splitlines()
+
+            cont = bool(self._title)
+            if not self.RE.search(quotelines[0]):
+                self._title = quotelines.pop(0)
+
+            admonition = etree.SubElement(parent, "div")
+            admonition.set(
+                "class", f"admonition quote{' continued' if cont else ''}"
+            )
+            self.parser.parseChunk(admonition, self._title)
+
+            admonition[0].set("class", "admonition-title")
+            self.parser.parseChunk(
+                admonition, "\n".join(self.clean(line) for line in quotelines)
+            )
+
+        @classmethod
+        def clean(klass, line):
+            m = klass.RE.match(line)
+            return m.group(1) if m else line
+
+    def extendMarkdown(self, md):
+        md.registerExtension(self)
+        email_quote_proc = self.EmailQuoteBlockProcessor(md.parser)
+        md.parser.blockprocessors.register(email_quote_proc, "emailquote", 25)
 
 
 # [ PARTS GENERATION ] ########################################################
 
 
 # [ PARTS GENERATION ] ########################################################
@@ -225,17 +549,18 @@ 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 filewriter_fn(path, content, mode="w", **kwargs):
-    with open(path, mode, **kwargs) as out_f:
-        out_f.write(content)
+    def __hash__(self):
+        return hash(str(self.subtype) + "".join(str(self.children)))
 
 
 def collect_inline_images(
 
 
 def collect_inline_images(
-    images, *, tempdir=None, filewriter_fn=filewriter_fn
+    image_registry, *, tempdir=None, filefactory=FileFactory()
 ):
     relparts = []
 ):
     relparts = []
-    for path, info in images.items():
+    for path, info in image_registry.items():
+        if path.startswith("cid:"):
+            continue
+
         data = request.urlopen(path)
 
         mimetype = data.headers["Content-Type"]
         data = request.urlopen(path)
 
         mimetype = data.headers["Content-Type"]
@@ -243,105 +568,278 @@ def collect_inline_images(
         tempfilename = tempfile.mkstemp(prefix="img", suffix=ext, dir=tempdir)
         path = pathlib.Path(tempfilename[1])
 
         tempfilename = tempfile.mkstemp(prefix="img", suffix=ext, dir=tempdir)
         path = pathlib.Path(tempfilename[1])
 
-        filewriter_fn(path, data.read(), "w+b")
+        with filefactory(path, "w+b") as out_f:
+            out_f.write(data.read())
 
 
+        # filewriter_fn(path, data.read(), "w+b")
+
+        desc = (
+            f'Inline image: "{info.desc}"'
+            if info.desc
+            else f"Inline image {str(len(relparts)+1)}"
+        )
         relparts.append(
         relparts.append(
-            Part(*mimetype.split("/"), path, cid=info.cid, desc=info.desc)
+            Part(*mimetype.split("/"), path, cid=info.cid, desc=desc)
         )
 
     return relparts
 
 
         )
 
     return relparts
 
 
+EMAIL_SIG_SEP = "\n-- \n"
+HTML_SIG_MARKER = "=htmlsig "
+
+
+def make_html_doc(body, sig=None):
+    ret = (
+        "<!DOCTYPE html>\n"
+        "<html>\n"
+        "<head>\n"
+        '<meta http-equiv="content-type" content="text/html; charset=UTF-8">\n'  # noqa: E501
+        '<meta name="viewport" content="width=device-width, initial-scale=1.0">\n'  # noqa: E501
+        "</head>\n"
+        "<body>\n"
+        f"{body}\n"
+    )
+
+    if sig:
+        nl = "\n"
+        ret = (
+            f'{ret}<div id="signature"><span class="sig_separator">{EMAIL_SIG_SEP.strip(nl)}</span>\n'  # noqa: E501
+            f"{sig}\n"
+            "</div>"
+        )
+
+    return f"{ret}\n  </body>\n</html>"
+
+
+def make_text_mail(text, sig=None):
+    return EMAIL_SIG_SEP.join((text, sig)) if sig else text
+
+
+def extract_signature(text, *, filefactory=FileFactory()):
+    parts = text.split(EMAIL_SIG_SEP, 1)
+    if len(parts) == 1:
+        return text, None, None
+
+    lines = parts[1].splitlines()
+    if lines[0].startswith(HTML_SIG_MARKER):
+        path = pathlib.Path(re.split(r" +", lines.pop(0), maxsplit=1)[1])
+        textsig = "\n".join(lines)
+
+        sig_input = filefactory(path.expanduser()).read()
+        soup = bs4.BeautifulSoup(sig_input, "html.parser")
+
+        style = str(soup.style.extract()) if soup.style else ""
+        for sig_selector in (
+            "#signature",
+            "#signatur",
+            "#emailsig",
+            ".signature",
+            ".signatur",
+            ".emailsig",
+            "body",
+            "div",
+        ):
+            sig = soup.select_one(sig_selector)
+            if sig:
+                break
+
+        if not sig:
+            return parts[0], textsig, style + sig_input
+
+        if sig.attrs.get("id") == "signature":
+            sig = "".join(str(c) for c in sig.children)
+
+        return parts[0], textsig, style + str(sig)
+
+    return parts[0], parts[1], None
+
+
 def convert_markdown_to_html(
 def convert_markdown_to_html(
-    origtext,
-    draftpath,
+    draft_f,
     *,
     *,
-    filewriter_fn=filewriter_fn,
+    related_to_html_only=False,
+    css_f=None,
+    htmldump_f=None,
+    filefactory=FileFactory(),
     tempdir=None,
     extensions=None,
     tempdir=None,
     extensions=None,
+    extension_configs=None,
 ):
 ):
-    origtext, htmltext, images = markdown_with_inline_image_support(
-        origtext, extensions=extensions
+    # TODO extension_configs need to be handled differently
+    extension_configs = extension_configs or {}
+    extension_configs.setdefault("pymdownx.highlight", {})[
+        "css_class"
+    ] = _CODEHILITE_CLASS
+
+    extensions = extensions or []
+    extensions.append(QuoteToAdmonitionExtension())
+
+    draft = draft_f.read()
+    origtext, textsig, htmlsig = extract_signature(
+        draft, filefactory=filefactory
     )
 
     )
 
-    filewriter_fn(draftpath, origtext, encoding="utf-8")
-    textpart = Part(
-        "text", "plain", draftpath, "Plain-text version", orig=True
+    (
+        origtext,
+        htmltext,
+        image_registry,
+        mdwn,
+    ) = markdown_with_inline_image_support(
+        origtext, extensions=extensions, extension_configs=extension_configs
     )
 
     )
 
-    htmlpath = draftpath.with_suffix(".html")
-    filewriter_fn(
-        htmlpath, htmltext, encoding="utf-8", errors="xmlcharrefreplace"
+    if htmlsig:
+        if not textsig:
+            # TODO: decide what to do if there is no plain-text version
+            raise NotImplementedError("HTML signature but no text alternative")
+
+        soup = bs4.BeautifulSoup(htmlsig, "html.parser")
+        for img in soup.find_all("img"):
+            uri = img.attrs["src"]
+            desc = img.attrs.get("title", img.attrs.get("alt"))
+            cid = image_registry.register(uri, desc)
+            img.attrs["src"] = f"cid:{cid}"
+
+        htmlsig = str(soup)
+
+    elif textsig:
+        (
+            textsig,
+            htmlsig,
+            image_registry,
+            mdwn,
+        ) = markdown_with_inline_image_support(
+            textsig,
+            extensions=extensions,
+            extension_configs=extension_configs,
+            image_registry=image_registry,
+            mdwn=mdwn,
+        )
+
+    origtext = make_text_mail(origtext, textsig)
+    draft_f.write(origtext)
+    textpart = Part(
+        "text", "plain", draft_f.path, "Plain-text version", orig=True
     )
     )
+
+    htmltext = make_html_doc(htmltext, htmlsig)
+    htmltext = apply_styling(htmltext, css_f.read() if css_f else None)
+
+    if draft_f.path:
+        htmlpath = draft_f.path.with_suffix(".html")
+    else:
+        htmlpath = pathlib.Path(
+            tempfile.mkstemp(suffix=".html", dir=tempdir)[1]
+        )
+    with filefactory(
+        htmlpath, "w", encoding="utf-8", errors="xmlcharrefreplace"
+    ) as out_f:
+        out_f.write(htmltext)
     htmlpart = Part("text", "html", htmlpath, "HTML version")
 
     htmlpart = Part("text", "html", htmlpath, "HTML version")
 
-    altpart = Multipart(
-        "alternative", [textpart, htmlpart], "Group of alternative content"
-    )
+    if htmldump_f:
+        htmldump_f.write(htmltext)
 
     imgparts = collect_inline_images(
 
     imgparts = collect_inline_images(
-        images, tempdir=tempdir, filewriter_fn=filewriter_fn
+        image_registry, tempdir=tempdir, filefactory=filefactory
     )
     )
-    if imgparts:
+
+    if related_to_html_only:
+        # If there are inline image part, they will be contained within a
+        # multipart/related part along with the HTML part only
+        if imgparts:
+            # replace htmlpart with a multipart/related container of the HTML
+            # parts and the images
+            htmlpart = Multipart(
+                "relative", [htmlpart] + imgparts, "Group of related content"
+            )
+
         return Multipart(
         return Multipart(
-            "relative", [altpart] + imgparts, "Group of related content"
+            "alternative", [textpart, htmlpart], "Group of alternative content"
         )
         )
+
     else:
     else:
-        return altpart
+        # If there are inline image part, they will be siblings to the
+        # multipart/alternative tree within a multipart/related part
+        altpart = Multipart(
+            "alternative", [textpart, htmlpart], "Group of alternative content"
+        )
+        if imgparts:
+            return Multipart(
+                "relative", [altpart] + imgparts, "Group of related content"
+            )
+        else:
+            return altpart
 
 
 class MIMETreeDFWalker:
     def __init__(self, *, visitor_fn=None, debug=False):
 
 
 class MIMETreeDFWalker:
     def __init__(self, *, visitor_fn=None, debug=False):
-        self._visitor_fn = visitor_fn
+        self._visitor_fn = visitor_fn or self._echovisit
         self._debug = debug
 
         self._debug = debug
 
+    def _echovisit(self, node, ancestry, debugprint):
+        debugprint(f"node={node} ancestry={ancestry}")
+
     def walk(self, root, *, visitor_fn=None):
         """
         Recursive function to implement a depth-dirst walk of the MIME-tree
         rooted at `root`.
         """
     def walk(self, root, *, visitor_fn=None):
         """
         Recursive function to implement a depth-dirst walk of the MIME-tree
         rooted at `root`.
         """
-
         if isinstance(root, list):
         if isinstance(root, list):
-            root = Multipart("mixed", children=root)
+            if len(root) > 1:
+                root = Multipart("mixed", children=root)
+            else:
+                root = root[0]
 
         self._walk(
             root,
 
         self._walk(
             root,
-            stack=[],
+            ancestry=[],
+            descendents=[],
             visitor_fn=visitor_fn or self._visitor_fn,
         )
 
             visitor_fn=visitor_fn or self._visitor_fn,
         )
 
-    def _walk(self, node, *, stack, visitor_fn):
+    def _walk(self, node, *, ancestry, descendents, visitor_fn):
         # Let's start by enumerating the parts at the current level. At the
         # Let's start by enumerating the parts at the current level. At the
-        # root level, stack will be the empty list, and we expect a multipart/*
-        # container at this level. Later, e.g. within a mutlipart/alternative
-        # container, the subtree will just be the alternative parts, while the
-        # top of the stack will be the multipart/alternative container, which
-        # we will process after the following loop.
-
-        lead = f"{'| '*len(stack)}|-"
+        # root level, ancestry will be the empty list, and we expect a
+        # multipart/* container at this level. Later, e.g. within a
+        # mutlipart/alternative container, the subtree will just be the
+        # alternative parts, while the top of the ancestry will be the
+        # multipart/alternative container, which we will process after the
+        # following loop.
+
+        lead = f"{'│ '*len(ancestry)}"
         if isinstance(node, Multipart):
             self.debugprint(
         if isinstance(node, Multipart):
             self.debugprint(
-                f"{lead}{node} parents={[s.subtype for s in stack]}"
+                f"{lead}├{node} ancestry={[s.subtype for s in ancestry]}"
             )
 
             )
 
-            # Depth-first, so push the current container onto the stack,
-            # then descend …
-            stack.append(node)
-            self.debugprint("| " * (len(stack) + 1))
+            # Depth-first, so push the current container onto the ancestry
+            # stack, then descend …
+            ancestry.append(node)
+            self.debugprint(lead + "│ " * 2)
             for child in node.children:
                 self._walk(
                     child,
             for child in node.children:
                 self._walk(
                     child,
-                    stack=stack,
+                    ancestry=ancestry,
+                    descendents=descendents,
                     visitor_fn=visitor_fn,
                 )
                     visitor_fn=visitor_fn,
                 )
-            self.debugprint("| " * len(stack))
-            assert stack.pop() == node
+            assert ancestry.pop() == node
+            sibling_descendents = descendents
+            descendents.extend(node.children)
 
         else:
 
         else:
-            self.debugprint(f"{lead}{node}")
+            self.debugprint(f"{lead}├{node}")
+            sibling_descendents = descendents
+
+        if False and ancestry:
+            self.debugprint(lead[:-1] + " │")
 
         if visitor_fn:
 
         if visitor_fn:
-            visitor_fn(node, stack, debugprint=self.debugprint)
+            visitor_fn(
+                node, ancestry, sibling_descendents, debugprint=self.debugprint
+            )
 
     def debugprint(self, s, **kwargs):
         if self._debug:
 
     def debugprint(self, s, **kwargs):
         if self._debug:
@@ -379,7 +877,7 @@ class MuttCommands:
             self._cmd1.append(s)
 
     def push(self, s):
             self._cmd1.append(s)
 
     def push(self, s):
-        s = s.replace('"', '"')
+        s = s.replace('"', r"\"")
         s = f'push "{s}"'
         self.debugprint(s)
         self._push.insert(0, s)
         s = f'push "{s}"'
         self.debugprint(s)
         self._push.insert(0, s)
@@ -396,26 +894,18 @@ class MuttCommands:
 
 
 def do_setup(
 
 
 def do_setup(
-    extensions=None,
     *,
     out_f=sys.stdout,
     temppath=None,
     tempdir=None,
     debug_commands=False,
 ):
     *,
     out_f=sys.stdout,
     temppath=None,
     tempdir=None,
     debug_commands=False,
 ):
-    extensions = extensions or []
     temppath = temppath or pathlib.Path(
         tempfile.mkstemp(prefix="muttmdwn-", dir=tempdir)[1]
     )
     cmds = MuttCommands(out_f, debug=debug_commands)
 
     temppath = temppath or pathlib.Path(
         tempfile.mkstemp(prefix="muttmdwn-", dir=tempdir)[1]
     )
     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)}'
-    if tempdir:
-        editor = f"{editor} --tempdir {tempdir}"
-    if debug_commands:
-        editor = f"{editor} --debug-commands"
+    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"')
@@ -428,11 +918,15 @@ def do_setup(
 
 def do_massage(
     draft_f,
 
 def do_massage(
     draft_f,
-    draftpath,
     cmd_f,
     *,
     extensions=None,
     cmd_f,
     *,
     extensions=None,
+    css_f=None,
+    htmldump_f=None,
     converter=convert_markdown_to_html,
     converter=convert_markdown_to_html,
+    related_to_html_only=True,
+    only_build=False,
+    max_other_attachments=20,
     tempdir=None,
     debug_commands=False,
     debug_walk=False,
     tempdir=None,
     debug_commands=False,
     debug_walk=False,
@@ -456,16 +950,27 @@ def do_massage(
     cmds.flush()
 
     extensions = extensions.split(",") if extensions else []
     cmds.flush()
 
     extensions = extensions.split(",") if extensions else []
-    tree = converter(draft_f.read(), draftpath, tempdir=tempdir, extensions=extensions)
+    tree = converter(
+        draft_f,
+        css_f=css_f,
+        htmldump_f=htmldump_f,
+        related_to_html_only=related_to_html_only,
+        tempdir=tempdir,
+        extensions=extensions,
+    )
 
     mimetree = MIMETreeDFWalker(debug=debug_walk)
 
 
     mimetree = MIMETreeDFWalker(debug=debug_walk)
 
-    def visitor_fn(item, stack, *, debugprint=None):
+    state = dict(pos=1, tags={}, parts=1)
+
+    def visitor_fn(item, ancestry, descendents, *, debugprint=None):
         """
         Visitor function called for every node (part) of the MIME tree,
         depth-first, and responsible for telling NeoMutt how to assemble
         the tree.
         """
         """
         Visitor function called for every node (part) of the MIME 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.
@@ -475,44 +980,101 @@ def do_massage(
                 # 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:
                 # 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("<first-entry>")
                 cmds.push("<update-encoding>")
                 cmds.push("<update-encoding>")
+
+                # We really just need to be able to assume that at this point,
+                # NeoMutt is at position 1, and that we've processed only this
+                # part so far. Nevermind about actual attachments, we can
+                # safely ignore those as they stay at the end.
+                assert state["pos"] == 1
+                assert state["parts"] == 1
             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>")
 
             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>")
 
+                # This added a part at the end of the list of parts, and that's
+                # just how many parts we've seen so far, so it's position in
+                # the NeoMutt compose list is the count of parts
+                state["parts"] += 1
+                state["pos"] = state["parts"]
+
             # If the item (including the original) comes with additional
             # information, then we might just as well update the NeoMutt
             # tree now:
             if item.cid:
             # If the item (including the original) comes with additional
             # information, then we might just as well update the NeoMutt
             # tree now:
             if item.cid:
-                cmds.push(f"<edit-content-id>\\Ca\\Ck{item.cid}<enter>")
+                cmds.push(f"<edit-content-id>{KILL_LINE}{item.cid}<enter>")
+
+            # Now for the biggest hack in this script, which is to handle
+            # attachments, such as PDFs, that aren't related or alternatives.
+            # The problem is that when we add an inline image, it always gets
+            # appended to the list, i.e. inserted *after* other attachments.
+            # Since we don't know the number of attachments, we also cannot
+            # infer the postition of the new attachment. Therefore, we bubble
+            # it all the way to the top, only to then move it down again:
+            if state["pos"] > 1:  # skip for the first part
+                for i in range(max_other_attachments):
+                    # could use any number here, but has to be larger than the
+                    # number of possible attachments. The performance
+                    # difference of using a high number is negligible.
+                    # Bubble up the new part
+                    cmds.push("<move-up>")
+
+                # As we push the part to the right position in the list (i.e.
+                # the last of the subset of attachments this script added), we
+                # must handle the situation that subtrees are skipped by
+                # NeoMutt. Hence, the actual number of positions to move down
+                # is decremented by the number of descendents so far
+                # encountered.
+                for i in range(1, state["pos"] - len(descendents)):
+                    cmds.push("<move-down>")
 
         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
-            # above), and so they have been tagged in NeoMutt's compose
-            # window. Now it's just a matter of telling NeoMutt to do the
-            # appropriate grouping:
+            # above). The tags dictionary of State should contain a list of
+            # their positions in the NeoMutt compose window, so iterate those
+            # and tag the parts there:
+            n_tags = len(state["tags"][item])
+            for tag in state["tags"][item]:
+                cmds.push(f"<jump>{tag}<enter><tag-entry>")
+
             if item.subtype == "alternative":
                 cmds.push("<group-alternatives>")
             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>")
+            else:
+                raise NotImplementedError(
+                    f"Handling of multipart/{item.subtype} is not implemented"
+                )
+
+            state["pos"] -= n_tags - 1
+            state["parts"] += 1
 
         else:
             # We should never get here
 
         else:
             # We should never get here
-            assert not "is valid part"
+            raise RuntimeError(f"Type {type(item)} is unexpected: {item}")
 
         # If the item has a description, we might just as well add it
         if item.desc:
 
         # If the item has a description, we might just as well add it
         if item.desc:
-            cmds.push(f"<edit-description>\\Ca\\Ck{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:
-        if stack:
-            cmds.push("<tag-entry>")
+            cmds.push(f"<edit-description>{KILL_LINE}{item.desc}<enter>")
+
+        if ancestry:
+            # If there's an ancestry, record the current (assumed) position in
+            # the NeoMutt compose window as needed-to-tag by our direct parent
+            # (i.e. the last item of the ancestry)
+            state["tags"].setdefault(ancestry[-1], []).append(state["pos"])
+
+            lead = "│ " * (len(ancestry) + 1) + "* "
+            debugprint(
+                f"{lead}ancestry={[a.subtype for a in ancestry]}\n"
+                f"{lead}descendents={[d.subtype for d in descendents]}\n"
+                f"{lead}children_positions={state['tags'][ancestry[-1]]}\n"
+                f"{lead}pos={state['pos']}, parts={state['parts']}"
+            )
 
     # -----------------
     # End of visitor_fn
 
     # -----------------
     # End of visitor_fn
@@ -521,6 +1083,9 @@ 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:
@@ -537,25 +1102,28 @@ def do_massage(
 if __name__ == "__main__":
     args = parse_cli_args()
 
 if __name__ == "__main__":
     args = parse_cli_args()
 
-    if args.mode == "setup":
-        if args.send_message:
-            raise NotImplementedError()
-
+    if args.mode is None:
         do_setup(
         do_setup(
-            args.extensions,
             tempdir=args.tempdir,
             debug_commands=args.debug_commands,
         )
 
     elif args.mode == "massage":
             tempdir=args.tempdir,
             debug_commands=args.debug_commands,
         )
 
     elif args.mode == "massage":
-        with open(args.MAILDRAFT, "r") as draft_f, open(
-            args.cmdpath, "w"
-        ) as cmd_f:
+        with (
+            File(args.MAILDRAFT, "r+") as draft_f,
+            File(args.cmdpath, "w") as cmd_f,
+            File(args.css_file, "r") as css_f,
+            File(args.dump_html, "w") as htmldump_f,
+        ):
             do_massage(
                 draft_f,
             do_massage(
                 draft_f,
-                pathlib.Path(args.MAILDRAFT),
                 cmd_f,
                 extensions=args.extensions,
                 cmd_f,
                 extensions=args.extensions,
+                css_f=css_f,
+                htmldump_f=htmldump_f,
+                related_to_html_only=args.related_to_html_only,
+                max_other_attachments=args.max_number_other_attachments,
+                only_build=args.only_build,
                 tempdir=args.tempdir,
                 debug_commands=args.debug_commands,
                 debug_walk=args.debug_walk,
                 tempdir=args.tempdir,
                 debug_commands=args.debug_commands,
                 debug_walk=args.debug_walk,
@@ -566,20 +1134,28 @@ if __name__ == "__main__":
 
 try:
     import pytest
 
 try:
     import pytest
-    from io import StringIO
 
     class Tests:
         @pytest.fixture
         def const1(self):
 
     class Tests:
         @pytest.fixture
         def const1(self):
-            return "CONSTANT STRING 1"
+            return "Curvature Vest Usher Dividing+T#iceps Senior"
 
         @pytest.fixture
         def const2(self):
 
         @pytest.fixture
         def const2(self):
-            return "CONSTANT STRING 2"
+            return "Habitant Celestial 2litzy Resurf/ce Headpiece Harmonics"
+
+        @pytest.fixture
+        def fakepath(self):
+            return pathlib.Path("/does/not/exist")
+
+        @pytest.fixture
+        def fakepath2(self):
+            return pathlib.Path("/does/not/exist/either")
 
         # NOTE: tests using the capsys fixture must specify sys.stdout to the
         # functions they call, else old stdout is used and not captured
 
 
         # NOTE: tests using the capsys fixture must specify sys.stdout to the
         # functions they call, else old stdout is used and not captured
 
+        @pytest.mark.muttctrl
         def test_MuttCommands_cmd(self, const1, const2, capsys):
             "Assert order of commands"
             cmds = MuttCommands(out_f=sys.stdout)
         def test_MuttCommands_cmd(self, const1, const2, capsys):
             "Assert order of commands"
             cmds = MuttCommands(out_f=sys.stdout)
@@ -589,6 +1165,7 @@ try:
             captured = capsys.readouterr()
             assert captured.out == "\n".join((const1, const2, ""))
 
             captured = capsys.readouterr()
             assert captured.out == "\n".join((const1, const2, ""))
 
+        @pytest.mark.muttctrl
         def test_MuttCommands_push(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)
         def test_MuttCommands_push(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)
@@ -601,6 +1178,15 @@ try:
                 == ('"\npush "'.join(("", const2, const1, "")))[2:-6]
             )
 
                 == ('"\npush "'.join(("", const2, const1, "")))[2:-6]
             )
 
+        @pytest.mark.muttctrl
+        def test_MuttCommands_push_escape(self, const1, const2, capsys):
+            cmds = MuttCommands(out_f=sys.stdout)
+            cmds.push(f'"{const1}"')
+            cmds.flush()
+            captured = capsys.readouterr()
+            assert f'"\\"{const1}\\""' in captured.out
+
+        @pytest.mark.muttctrl
         def test_MuttCommands_cmd_push_mixed(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)
         def test_MuttCommands_cmd_push_mixed(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)
@@ -624,7 +1210,7 @@ try:
             assert lines[5] in lines_out[7]
 
         @pytest.fixture
             assert lines[5] in lines_out[7]
 
         @pytest.fixture
-        def basic_mime_tree(self):
+        def mime_tree_related_to_alternative(self):
             return Multipart(
                 "relative",
                 children=[
             return Multipart(
                 "relative",
                 children=[
@@ -649,185 +1235,322 @@ try:
                 desc="Related",
             )
 
                 desc="Related",
             )
 
-        def test_MIMETreeDFWalker_depth_first_walk(self, basic_mime_tree):
+        @pytest.fixture
+        def mime_tree_related_to_html(self):
+            return Multipart(
+                "alternative",
+                children=[
+                    Part(
+                        "text",
+                        "plain",
+                        "part.txt",
+                        desc="Plain",
+                        orig=True,
+                    ),
+                    Multipart(
+                        "relative",
+                        children=[
+                            Part("text", "html", "part.html", desc="HTML"),
+                            Part(
+                                "text",
+                                "png",
+                                "logo.png",
+                                cid="logo.png",
+                                desc="Logo",
+                            ),
+                        ],
+                        desc="Related",
+                    ),
+                ],
+                desc="Alternative",
+            )
+
+        @pytest.fixture
+        def mime_tree_nested(self):
+            return Multipart(
+                "relative",
+                children=[
+                    Multipart(
+                        "alternative",
+                        children=[
+                            Part(
+                                "text",
+                                "plain",
+                                "part.txt",
+                                desc="Plain",
+                                orig=True,
+                            ),
+                            Multipart(
+                                "alternative",
+                                children=[
+                                    Part(
+                                        "text",
+                                        "plain",
+                                        "part.txt",
+                                        desc="Nested plain",
+                                    ),
+                                    Part(
+                                        "text",
+                                        "html",
+                                        "part.html",
+                                        desc="Nested HTML",
+                                    ),
+                                ],
+                                desc="Nested alternative",
+                            ),
+                        ],
+                        desc="Alternative",
+                    ),
+                    Part(
+                        "text",
+                        "png",
+                        "logo.png",
+                        cid="logo.png",
+                        desc="Logo",
+                    ),
+                ],
+                desc="Related",
+            )
+
+        @pytest.mark.treewalk
+        def test_MIMETreeDFWalker_depth_first_walk(
+            self, mime_tree_related_to_alternative
+        ):
             mimetree = MIMETreeDFWalker()
 
             items = []
 
             mimetree = MIMETreeDFWalker()
 
             items = []
 
-            def visitor_fn(item, stack, debugprint):
-                items.append((item, len(stack)))
+            def visitor_fn(item, ancestry, descendents, debugprint):
+                items.append((item, len(ancestry), len(descendents)))
 
 
-            mimetree.walk(basic_mime_tree, visitor_fn=visitor_fn)
+            mimetree.walk(
+                mime_tree_related_to_alternative, visitor_fn=visitor_fn
+            )
             assert len(items) == 5
             assert items[0][0].subtype == "plain"
             assert items[0][1] == 2
             assert len(items) == 5
             assert items[0][0].subtype == "plain"
             assert items[0][1] == 2
+            assert items[0][2] == 0
             assert items[1][0].subtype == "html"
             assert items[1][1] == 2
             assert items[1][0].subtype == "html"
             assert items[1][1] == 2
+            assert items[1][2] == 0
             assert items[2][0].subtype == "alternative"
             assert items[2][1] == 1
             assert items[2][0].subtype == "alternative"
             assert items[2][1] == 1
+            assert items[2][2] == 2
             assert items[3][0].subtype == "png"
             assert items[3][1] == 1
             assert items[3][0].subtype == "png"
             assert items[3][1] == 1
+            assert items[3][2] == 2
             assert items[4][0].subtype == "relative"
             assert items[4][1] == 0
             assert items[4][0].subtype == "relative"
             assert items[4][1] == 0
+            assert items[4][2] == 4
 
 
-        def test_MIMETreeDFWalker_list_to_mixed(self, basic_mime_tree):
+        @pytest.mark.treewalk
+        def test_MIMETreeDFWalker_list_to_mixed(self, const1):
             mimetree = MIMETreeDFWalker()
             items = []
 
             mimetree = MIMETreeDFWalker()
             items = []
 
-            def visitor_fn(item, stack, debugprint):
+            def visitor_fn(item, ancestry, descendents, debugprint):
                 items.append(item)
 
                 items.append(item)
 
-            mimetree.walk([basic_mime_tree], visitor_fn=visitor_fn)
+            p = Part("text", "plain", const1)
+            mimetree.walk([p], visitor_fn=visitor_fn)
+            assert items[-1].subtype == "plain"
+            mimetree.walk([p, p], visitor_fn=visitor_fn)
             assert items[-1].subtype == "mixed"
 
             assert items[-1].subtype == "mixed"
 
+        @pytest.mark.treewalk
         def test_MIMETreeDFWalker_visitor_in_constructor(
         def test_MIMETreeDFWalker_visitor_in_constructor(
-            self, basic_mime_tree
+            self, mime_tree_related_to_alternative
         ):
             items = []
 
         ):
             items = []
 
-            def visitor_fn(item, stack, debugprint):
+            def visitor_fn(item, ancestry, descendents, debugprint):
                 items.append(item)
 
             mimetree = MIMETreeDFWalker(visitor_fn=visitor_fn)
                 items.append(item)
 
             mimetree = MIMETreeDFWalker(visitor_fn=visitor_fn)
-            mimetree.walk(basic_mime_tree)
+            mimetree.walk(mime_tree_related_to_alternative)
             assert len(items) == 5
 
             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
-            )
-            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)
-
         @pytest.fixture
         def string_io(self, const1, text=None):
             return StringIO(text or const1)
 
         @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, extensions, tempdir):
-                return Part("text", "plain", draftpath, orig=True)
+        @pytest.mark.massage
+        def test_do_massage_basic(self):
+            def converter(draft_f, **kwargs):
+                return Part("text", "plain", draft_f.path, orig=True)
 
 
-            do_massage(
-                draft_f=string_io,
-                draftpath=const1,
-                cmd_f=sys.stdout,
-                converter=converter,
-            )
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()
 
 
-            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 '="$my_editor"' in lines.pop(0)
             assert '="$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 "update-encoding" in lines.pop(0)
+            assert "first-entry" in lines.pop(0)
             assert "source 'rm -f " in lines.pop(0)
             assert "unset my_mdwn_postprocess_cmd_file" == 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, 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 "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.mark.massage
+        def test_do_massage_fulltree(self, mime_tree_related_to_alternative):
+            def converter(draft_f, **kwargs):
+                return mime_tree_related_to_alternative
 
 
-        @pytest.fixture
-        def markdown_non_converter(self, const1, const2):
-            return lambda s, text: f"{const1}{text}{const2}"
+            max_attachments = 5
 
 
-        def test_converter_tree_basic(
-            self, const1, const2, fake_filewriter, markdown_non_converter
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    max_other_attachments=max_attachments,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()[4:-2]
+
+            assert "first-entry" in lines.pop()
+            assert "update-encoding" in lines.pop()
+            assert "Plain" in lines.pop()
+            assert "part.html" in lines.pop()
+            assert "toggle-unlink" in lines.pop()
+            for i in range(max_attachments):
+                assert "move-up" in lines.pop()
+            assert "move-down" in lines.pop()
+            assert "HTML" in lines.pop()
+            assert "jump>1" in lines.pop()
+            assert "jump>2" in lines.pop()
+            assert "group-alternatives" in lines.pop()
+            assert "Alternative" in lines.pop()
+            assert "logo.png" in lines.pop()
+            assert "toggle-unlink" in lines.pop()
+            assert "content-id" in lines.pop()
+            for i in range(max_attachments):
+                assert "move-up" in lines.pop()
+            assert "move-down" in lines.pop()
+            assert "Logo" in lines.pop()
+            assert "jump>1" in lines.pop()
+            assert "jump>4" in lines.pop()
+            assert "group-related" in lines.pop()
+            assert "Related" in lines.pop()
+            assert "send-message" in lines.pop()
+            assert len(lines) == 0
+
+        @pytest.mark.massage
+        def test_mime_tree_relative_within_alternative(
+            self, mime_tree_related_to_html
+        ):
+            def converter(draft_f, **kwargs):
+                return mime_tree_related_to_html
+
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()[4:-2]
+
+            assert "first-entry" in lines.pop()
+            assert "update-encoding" in lines.pop()
+            assert "Plain" in lines.pop()
+            assert "part.html" in lines.pop()
+            assert "toggle-unlink" in lines.pop()
+            assert "move-up" in lines.pop()
+            while True:
+                top = lines.pop()
+                if "move-up" not in top:
+                    break
+            assert "move-down" in top
+            assert "HTML" in lines.pop()
+            assert "logo.png" in lines.pop()
+            assert "toggle-unlink" in lines.pop()
+            assert "content-id" in lines.pop()
+            assert "move-up" in lines.pop()
+            while True:
+                top = lines.pop()
+                if "move-up" not in top:
+                    break
+            assert "move-down" in top
+            assert "move-down" in lines.pop()
+            assert "Logo" in lines.pop()
+            assert "jump>2" in lines.pop()
+            assert "jump>3" in lines.pop()
+            assert "group-related" in lines.pop()
+            assert "Related" in lines.pop()
+            assert "jump>1" in lines.pop()
+            assert "jump>2" in lines.pop()
+            assert "group-alternative" in lines.pop()
+            assert "Alternative" in lines.pop()
+            assert "send-message" in lines.pop()
+            assert len(lines) == 0
+
+        @pytest.mark.massage
+        def test_mime_tree_nested_trees_does_not_break_positioning(
+            self, mime_tree_nested
         ):
         ):
-            path = pathlib.Path(const2)
+            def converter(draft_f, **kwargs):
+                return mime_tree_nested
+
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()
+
+            while "logo.png" not in lines.pop():
+                pass
+            lines.pop()
+            assert "content-id" in lines.pop()
+            assert "move-up" in lines.pop()
+            while True:
+                top = lines.pop()
+                if "move-up" not in top:
+                    break
+            assert "move-down" in top
+            # Due to the nested trees, the number of descendents of the sibling
+            # actually needs to be considered, not just the nieces. So to move
+            # from position 1 to position 6, it only needs one <move-down>
+            # because that jumps over the entire sibling tree. Thus what
+            # follows next must not be another <move-down>
+            assert "Logo" in lines.pop()
+
+        @pytest.mark.converter
+        def test_converter_tree_basic(self, fakepath, const1, fakefilefactory):
+            draft_f = fakefilefactory(fakepath, content=const1)
             tree = convert_markdown_to_html(
             tree = convert_markdown_to_html(
-                const1, path, filewriter_fn=fake_filewriter
+                draft_f, filefactory=fakefilefactory
             )
 
             assert tree.subtype == "alternative"
             assert len(tree.children) == 2
             assert tree.children[0].subtype == "plain"
             )
 
             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].path == draft_f.path
             assert tree.children[0].orig
             assert tree.children[1].subtype == "html"
             assert tree.children[0].orig
             assert tree.children[1].subtype == "html"
-            assert tree.children[1].path == path.with_suffix(".html")
+            assert tree.children[1].path == fakepath.with_suffix(".html")
 
 
+        @pytest.mark.converter
         def test_converter_writes(
         def test_converter_writes(
-            self,
-            const1,
-            const2,
-            fake_filewriter,
-            monkeypatch,
-            markdown_non_converter,
+            self, fakepath, fakefilefactory, const1, monkeypatch
         ):
         ):
-            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
-                )
+            draft_f = fakefilefactory(fakepath, content=const1)
+            convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
 
 
-            assert (path, const1) == fake_filewriter.pop(0)
-            assert (
-                path.with_suffix(".html"),
-                markdown_non_converter(None, const1),
-            ) == fake_filewriter.pop(0)
+            html = fakefilefactory.pop()
+            assert fakepath.with_suffix(".html") == html[0]
+            assert const1 in html[1].read()
+            text = fakefilefactory.pop()
+            assert fakepath == text[0]
+            assert const1 == text[1].read()
 
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_processor(self):
             imgpath1 = "file:/path/to/image.png"
             imgpath2 = "file:///path/to/image.png?url=params"
         def test_markdown_inline_image_processor(self):
             imgpath1 = "file:/path/to/image.png"
             imgpath2 = "file:///path/to/image.png?url=params"
@@ -836,7 +1559,7 @@ try:
                        ![image inlined
                          with newline]({imgpath2})
                        ![image local path]({imgpath3})"""
                        ![image inlined
                          with newline]({imgpath2})
                        ![image local path]({imgpath3})"""
-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
 
             # local paths have been normalised to URLs:
             imgpath3 = f"file://{imgpath3}"
 
             # local paths have been normalised to URLs:
             imgpath3 = f"file://{imgpath3}"
@@ -851,44 +1574,59 @@ try:
             assert images[imgpath1].cid != images[imgpath3].cid
             assert images[imgpath2].cid != images[imgpath3].cid
 
             assert images[imgpath1].cid != images[imgpath3].cid
             assert images[imgpath2].cid != images[imgpath3].cid
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_processor_title_to_desc(self, const1):
             imgpath = "file:///path/to/image.png"
             text = f'![inline local image]({imgpath} "{const1}")'
         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)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
             assert images[imgpath].desc == const1
 
             assert images[imgpath].desc == const1
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_processor_alt_to_desc(self, const1):
             imgpath = "file:///path/to/image.png"
             text = f"![{const1}]({imgpath})"
         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)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
             assert images[imgpath].desc == const1
 
             assert images[imgpath].desc == const1
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_processor_title_over_alt_desc(
             self, const1, const2
         ):
             imgpath = "file:///path/to/image.png"
             text = f'![{const1}]({imgpath} "{const2}")'
         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)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
             assert images[imgpath].desc == const2
 
             assert images[imgpath].desc == const2
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_not_external(self):
             imgpath = "https://path/to/image.png"
             text = f"![inline image]({imgpath})"
         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)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
 
             assert 'src="cid:' not in html
             assert "](cid:" not in text
             assert len(images) == 0
 
 
             assert 'src="cid:' not in html
             assert "](cid:" not in text
             assert len(images) == 0
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_local_file(self):
             imgpath = "/path/to/image.png"
             text = f"![inline image]({imgpath})"
         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)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
 
             for k, v in images.items():
                 assert k == f"file://{imgpath}"
                 break
 
 
             for k, v in images.items():
                 assert k == f"file://{imgpath}"
                 break
 
+        @pytest.mark.imgproc
+        def test_markdown_inline_image_expanduser(self):
+            imgpath = pathlib.Path("~/image.png")
+            text = f"![inline image]({imgpath})"
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
+
+            for k, v in images.items():
+                assert k == f"file://{imgpath.expanduser()}"
+                break
+
         @pytest.fixture
         def test_png(self):
             return (
         @pytest.fixture
         def test_png(self):
             return (
@@ -896,45 +1634,531 @@ try:
                 "AAAABCAAAAAA6fptVAAAACklEQVQI12P4DwABAQEAG7buVgAA"
             )
 
                 "AAAABCAAAAAA6fptVAAAACklEQVQI12P4DwABAQEAG7buVgAA"
             )
 
+        @pytest.mark.imgproc
         def test_markdown_inline_image_processor_base64(self, test_png):
             text = f"![1px white inlined]({test_png})"
         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)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
 
             assert 'src="cid:' in html
             assert "](cid:" in text
             assert len(images) == 1
             assert test_png in images
 
 
             assert 'src="cid:' in html
             assert "](cid:" in text
             assert len(images) == 1
             assert test_png in images
 
+        @pytest.mark.converter
         def test_converter_tree_inline_image_base64(
         def test_converter_tree_inline_image_base64(
-            self, test_png, const1, fake_filewriter
+            self, test_png, fakefilefactory
         ):
             text = f"![inline base64 image]({test_png})"
         ):
             text = f"![inline base64 image]({test_png})"
-            path = pathlib.Path(const1)
-            tree = convert_markdown_to_html(
-                text, path, filewriter_fn=fake_filewriter
-            )
-
+            with fakefilefactory(content=text) as draft_f:
+                tree = convert_markdown_to_html(
+                    draft_f,
+                    filefactory=fakefilefactory,
+                    related_to_html_only=False,
+                )
             assert tree.subtype == "relative"
             assert tree.subtype == "relative"
+            assert tree.children[0].subtype == "alternative"
             assert tree.children[1].subtype == "png"
             assert tree.children[1].subtype == "png"
-            written = fake_filewriter.pop()
+            written = fakefilefactory.pop()
             assert tree.children[1].path == written[0]
             assert tree.children[1].path == written[0]
-            assert written[1] == request.urlopen(test_png).read()
+            assert b"PNG" in written[1].read()
+
+        @pytest.mark.converter
+        def test_converter_tree_inline_image_base64_related_to_html(
+            self, test_png, fakefilefactory
+        ):
+            text = f"![inline base64 image]({test_png})"
+            with fakefilefactory(content=text) as draft_f:
+                tree = convert_markdown_to_html(
+                    draft_f,
+                    filefactory=fakefilefactory,
+                    related_to_html_only=True,
+                )
+            assert tree.subtype == "alternative"
+            assert tree.children[1].subtype == "relative"
+            assert tree.children[1].children[1].subtype == "png"
+            written = fakefilefactory.pop()
+            assert tree.children[1].children[1].path == written[0]
+            assert b"PNG" in written[1].read()
+
+        @pytest.mark.converter
+        def test_converter_tree_inline_image_cid(
+            self, const1, fakefilefactory
+        ):
+            text = f"![inline base64 image](cid:{const1})"
+            with fakefilefactory(content=text) as draft_f:
+                tree = convert_markdown_to_html(
+                    draft_f,
+                    filefactory=fakefilefactory,
+                    related_to_html_only=False,
+                )
+            assert len(tree.children) == 2
+            assert tree.children[0].cid != const1
+            assert tree.children[0].type != "image"
+            assert tree.children[1].cid != const1
+            assert tree.children[1].type != "image"
+
+        @pytest.fixture
+        def fakefilefactory(self):
+            return FakeFileFactory()
 
 
+        @pytest.mark.imgcoll
         def test_inline_image_collection(
         def test_inline_image_collection(
-            self, test_png, const1, const2, fake_filewriter
+            self, test_png, const1, const2, fakefilefactory
         ):
             test_images = {test_png: InlineImageInfo(cid=const1, desc=const2)}
             relparts = collect_inline_images(
         ):
             test_images = {test_png: InlineImageInfo(cid=const1, desc=const2)}
             relparts = collect_inline_images(
-                test_images, filewriter_fn=fake_filewriter
+                test_images, filefactory=fakefilefactory
             )
 
             )
 
-            written = fake_filewriter.pop()
-            assert b"PNG" in written[1]
+            written = fakefilefactory.pop()
+            assert b"PNG" in written[1].read()
 
             assert relparts[0].subtype == "png"
             assert relparts[0].path == written[0]
             assert relparts[0].cid == const1
 
             assert relparts[0].subtype == "png"
             assert relparts[0].path == written[0]
             assert relparts[0].cid == const1
-            assert relparts[0].desc == const2
+            assert const2 in relparts[0].desc
+
+        if _PYNLINER:
+
+            @pytest.mark.styling
+            def test_apply_stylesheet(self):
+                html = "<p>Hello, world!</p>"
+                css = "p { color:red }"
+                out = apply_styling(html, css)
+                assert 'p style="color' in out
+
+            @pytest.mark.styling
+            def test_apply_no_stylesheet(self, const1):
+                out = apply_styling(const1, None)
+
+            @pytest.mark.massage
+            @pytest.mark.styling
+            def test_massage_styling_to_converter(self):
+                css = "p { color:red }"
+                css_f = File(content=css)
+                css_applied = []
+
+                def converter(draft_f, css_f, **kwargs):
+                    css = css_f.read()
+                    css_applied.append(css)
+                    return Part("text", "plain", draft_f.path, orig=True)
+
+                do_massage(
+                    draft_f=File(),
+                    cmd_f=File(),
+                    css_f=css_f,
+                    converter=converter,
+                )
+                assert css_applied[0] == css
+
+            @pytest.mark.converter
+            @pytest.mark.styling
+            def test_converter_apply_styles(
+                self, const1, monkeypatch, fakepath, fakefilefactory
+            ):
+                css = "p { color:red }"
+                with (
+                    monkeypatch.context() as m,
+                    fakefilefactory(fakepath, content=const1) as draft_f,
+                    fakefilefactory(content=css) as css_f,
+                ):
+                    m.setattr(
+                        markdown.Markdown,
+                        "convert",
+                        lambda s, t: f"<p>{t}</p>",
+                    )
+                    convert_markdown_to_html(
+                        draft_f, css_f=css_f, filefactory=fakefilefactory
+                    )
+                assert re.search(
+                    r"color:.*red",
+                    fakefilefactory[fakepath.with_suffix(".html")].read(),
+                )
+
+        if _PYGMENTS_CSS:
+
+            @pytest.mark.styling
+            def test_apply_stylesheet_pygments(self):
+                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
+
+        @pytest.mark.sig
+        def test_signature_extraction_no_signature(self, const1):
+            assert (const1, None, None) == extract_signature(const1)
+
+        @pytest.mark.sig
+        def test_signature_extraction_just_text(self, const1, const2):
+            origtext, textsig, htmlsig = extract_signature(
+                f"{const1}{EMAIL_SIG_SEP}{const2}"
+            )
+            assert origtext == const1
+            assert textsig == const2
+            assert htmlsig is None
+
+        @pytest.mark.sig
+        def test_signature_extraction_html(
+            self, fakepath, fakefilefactory, const1, const2
+        ):
+            sigconst = "HTML signature from {path} but as a string"
+            sig = f'<div id="signature">{sigconst.format(path=fakepath)}</div>'
+
+            sig_f = fakefilefactory(fakepath, content=sig)
+
+            origtext, textsig, htmlsig = extract_signature(
+                f"{const1}{EMAIL_SIG_SEP}{HTML_SIG_MARKER} {fakepath}\n{const2}",
+                filefactory=fakefilefactory,
+            )
+            assert origtext == const1
+            assert textsig == const2
+            assert htmlsig == sigconst.format(path=fakepath)
+
+        @pytest.mark.sig
+        def test_signature_extraction_file_not_found(self, const1):
+            path = pathlib.Path("/does/not/exist")
+            with pytest.raises(FileNotFoundError):
+                origtext, textsig, htmlsig = extract_signature(
+                    f"{const1}{EMAIL_SIG_SEP}{HTML_SIG_MARKER}{path}\n{const1}"
+                )
+
+        @pytest.mark.imgproc
+        def test_image_registry(self, const1):
+            reg = ImageRegistry()
+            cid = reg.register(const1)
+            assert "@" in cid
+            assert not cid.startswith("<")
+            assert not cid.endswith(">")
+            assert const1 in reg
+
+        @pytest.mark.imgproc
+        def test_image_registry_file_uri(self, const1):
+            reg = ImageRegistry()
+            reg.register("/some/path")
+            for path in reg:
+                assert path.startswith("file://")
+                break
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling(
+            self, fakepath, fakefilefactory, monkeypatch
+        ):
+            mailparts = (
+                "This is the mail body\n",
+                f"{EMAIL_SIG_SEP}",
+                "This is a plain-text signature only",
+            )
+
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+                monkeypatch.context() as m,
+            ):
+                m.setattr(markdown.Markdown, "convert", lambda s, t: t)
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            body = soup.body.contents
+
+            assert mailparts[0] in body.pop(0)
+
+            sig = soup.select_one("#signature")
+            assert sig == body.pop(0)
+
+            sep = sig.select_one("span.sig_separator")
+            assert sep == sig.contents[0]
+            assert f"\n{sep.text}\n" == EMAIL_SIG_SEP
+
+            assert mailparts[2] in sig.contents[1]
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling_htmlsig(
+            self, fakepath, fakepath2, fakefilefactory, monkeypatch
+        ):
+            mailparts = (
+                "This is the mail body",
+                f"{EMAIL_SIG_SEP}",
+                f"{HTML_SIG_MARKER}{fakepath2}\n",
+                "This is the plain-text version",
+            )
+            htmlsig = "HTML Signature from {path} but as a string"
+            html = (
+                f'<div id="signature"><p>{htmlsig.format(path=fakepath2)}</p></div>'
+            )
+
+            sig_f = fakefilefactory(fakepath2, content=html)
+
+            def mdwn_fn(t):
+                return t.upper()
+
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+                monkeypatch.context() as m,
+            ):
+                m.setattr(
+                    markdown.Markdown, "convert", lambda s, t: mdwn_fn(t)
+                )
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            sig = soup.select_one("#signature")
+            sig.span.extract()
+
+            assert HTML_SIG_MARKER not in sig.text
+            assert htmlsig.format(path=fakepath2) == sig.text.strip()
+
+            plaintext = fakefilefactory[fakepath].read()
+            assert plaintext.endswith(EMAIL_SIG_SEP + mailparts[-1])
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling_htmlsig_with_image(
+            self, fakepath, fakepath2, fakefilefactory, monkeypatch, test_png
+        ):
+            mailparts = (
+                "This is the mail body",
+                f"{EMAIL_SIG_SEP}",
+                f"{HTML_SIG_MARKER}{fakepath2}\n",
+                "This is the plain-text version",
+            )
+            htmlsig = (
+                "HTML Signature from {path} with image\n"
+                f'<img src="{test_png}">\n'
+            )
+            html = (
+                f'<div id="signature">{htmlsig.format(path=fakepath2)}</div>'
+            )
+
+            sig_f = fakefilefactory(fakepath2, content=html)
+
+            def mdwn_fn(t):
+                return t.upper()
+
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+                monkeypatch.context() as m,
+            ):
+                m.setattr(
+                    markdown.Markdown, "convert", lambda s, t: mdwn_fn(t)
+                )
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            assert fakefilefactory.pop()[0].suffix == ".png"
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            assert soup.img.attrs["src"].startswith("cid:")
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling_textsig_with_image(
+            self, fakepath, fakefilefactory, test_png
+        ):
+            mailparts = (
+                "This is the mail body",
+                f"{EMAIL_SIG_SEP}",
+                "This is the plain-text version with image\n",
+                f"![Inline]({test_png})",
+            )
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+            ):
+                tree = convert_markdown_to_html(
+                    draft_f, filefactory=fakefilefactory
+                )
+
+            assert tree.subtype == "relative"
+            assert tree.children[0].subtype == "alternative"
+            assert tree.children[1].subtype == "png"
+            written = fakefilefactory.pop()
+            assert tree.children[1].path == written[0]
+            assert written[1].read() == request.urlopen(test_png).read()
+
+        @pytest.mark.converter
+        def test_converter_attribution_to_admonition(
+            self, fakepath, fakefilefactory
+        ):
+            mailparts = (
+                "Regarding whatever",
+                "> blockquote line1",
+                "> blockquote line2",
+                "> ",
+                "> new para with **bold** text",
+            )
+            with fakefilefactory(
+                fakepath, content="\n".join(mailparts)
+            ) as draft_f:
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            quote = soup.select_one("div.admonition.quote")
+            assert quote
+            assert (
+                soup.select_one("p.admonition-title").extract().text.strip()
+                == mailparts[0]
+            )
+
+            p = quote.p.extract()
+            assert p.text.strip() == "\n".join(p[2:] for p in mailparts[1:3])
+
+            p = quote.p.extract()
+            assert p.contents[1].name == "strong"
+
+        @pytest.mark.converter
+        def test_converter_attribution_to_admonition_multiple(
+            self, fakepath, fakefilefactory
+        ):
+            mailparts = (
+                "Regarding whatever",
+                "> blockquote line1",
+                "> blockquote line2",
+                "",
+                "Normal text",
+                "",
+                "> continued emailquote",
+                "",
+                "Another email-quote",
+                "> something",
+            )
+            with fakefilefactory(
+                fakepath, content="\n".join(mailparts)
+            ) as draft_f:
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            quote = soup.select_one("div.admonition.quote.continued").extract()
+            assert quote
+            assert (
+                quote.select_one("p.admonition-title").extract().text.strip()
+                == mailparts[0]
+            )
+
+            p = quote.p.extract()
+            assert p
+
+            quote = soup.select_one("div.admonition.quote.continued").extract()
+            assert quote
+            assert (
+                quote.select_one("p.admonition-title").extract().text.strip()
+                == mailparts[-2]
+            )
+
+        @pytest.mark.fileio
+        def test_file_class_contextmanager(self, const1, monkeypatch):
+            state = dict(o=False, c=False)
+
+            def fn(t):
+                state[t] = True
+
+            with monkeypatch.context() as m:
+                m.setattr(File, "open", lambda s: fn("o"))
+                m.setattr(File, "close", lambda s: fn("c"))
+                with File() as f:
+                    assert state["o"]
+                    assert not state["c"]
+            assert state["c"]
+
+        @pytest.mark.fileio
+        def test_file_class_no_path(self, const1):
+            with File(mode="w+") as f:
+                f.write(const1, cache=False)
+                assert f.read(cache=False) == const1
+
+        @pytest.mark.fileio
+        def test_file_class_path(self, const1, tmp_path):
+            with File(tmp_path / "file", mode="w+") as f:
+                f.write(const1, cache=False)
+                assert f.read(cache=False) == const1
+
+        @pytest.mark.fileio
+        def test_file_class_cache(self, tmp_path, const1, const2):
+            path = tmp_path / "file"
+            file = File(path, mode="w+")
+            with file as f:
+                f.write(const1, cache=True)
+            with open(path, mode="w") as f:
+                f.write(const2)
+            with file as f:
+                assert f.read(cache=True) == const1
+
+        @pytest.mark.fileio
+        def test_file_class_cache_init(self, const1):
+            file = File(path=None, mode="r", content=const1)
+            with file as f:
+                assert f.read() == const1
+
+        @pytest.mark.fileio
+        def test_file_class_content_or_path(self, fakepath, const1):
+            with pytest.raises(RuntimeError):
+                file = File(path=fakepath, content=const1)
+
+        @pytest.mark.fileio
+        def test_file_class_content_needs_read(self, const1):
+            with pytest.raises(RuntimeError):
+                file = File(mode="w", content=const1)
+
+        @pytest.mark.fileio
+        def test_file_class_write_persists_close(self, const1):
+            f = File(mode="w+")
+            with f:
+                f.write(const1)
+            with f:
+                assert f.read() == const1
+
+        @pytest.mark.fileio
+        def test_file_class_write_resets_read_cache(self, const1, const2):
+            with File(mode="w+", content=const1) as f:
+                assert f.read() == const1
+                f.write(const2)
+                assert f.read() == const2
+
+        @pytest.mark.fileio
+        def test_file_factory(self):
+            fact = FileFactory()
+            f = fact()
+            assert isinstance(f, File)
+            assert len(fact) == 1
+            assert f in fact
+            assert f == fact[0]
+
+        @pytest.mark.fileio
+        def test_fake_file_factory(self, fakepath, fakefilefactory):
+            fact = FakeFileFactory()
+            f = fakefilefactory(fakepath)
+            assert f.path == fakepath
+            assert f == fakefilefactory[fakepath]
+
+        @pytest.mark.fileio
+        def test_fake_file_factory_path_persistence(
+            self, fakepath, fakefilefactory
+        ):
+            f1 = fakefilefactory(fakepath)
+            assert f1 == fakefilefactory(fakepath)
 
 except ImportError:
     pass
 
 except ImportError:
     pass