mdbook/tests/testsuite/markdown.rs
Eric Huss 2b242494b0 Add a new HTML rendering pipeline
This rewrites the HTML rendering pipeline to use a tree data structure,
and implements a custom HTML serializer. The intent is to make it easier
to make changes and to manipulate the output. This should make some
future changes much easier.

This is a large change, but I'll try to briefly summarize what's
changing:

- All of the HTML rendering support has been moved out of
  mdbook-markdown into mdbook-html. For now, all of the API surface is
  private, though we may consider ways to safely expose it in the
  future.
- Instead of using pulldown-cmark's html serializer, this takes the
  pulldown-cmark events and translates them into a tree data structure
  (using the ego-tree crate to define the tree). See `tree.rs`.
- HTML in the markdown document is parsed using html5ever, and then
  lives inside the same tree data structure. See `tokenizer.rs`.
- Transformations are then applied to the tree data structure. For
  example, adding header links or hiding code lines.
- Serialization is a simple process of writing out the nodes to a
  string. See `serialize.rs`.
- The search indexer works on the tree structure instead of re-rendering
  every chapter twice. See `html_handlebars/search.rs`.
- The print page now takes a very different approach of taking the
  same tree structure built for rendering the chapters, and applies
  transformations to it. This avoid re-parsing everything again. See
  `print.rs`.
    - I changed the linking behavior so that links on the print page
      link to items on the print page instead of outside the print page.
- There are a variety of small changes to how it serializes as can be
  seen in the changes to the tests. Some highlights:
	- Code blocks no longer have a second layer of `<pre>` tags wrapping
      it.
    - Fixed a minor issue where a rust code block with a specific
      edition was having the wrong classes when there was a default
      edition.
- Drops the ammonia dependency, which significantly reduces the number
  of dependencies. It was only being used for a very minor task, and
  we can handle it much more easily now.
- Drops `pretty_assertions`, they are no longer used (mostly being
  migrated to the testsuite).

There's obviously a lot of risk trying to parse everything to such a low
level, but I think the benefits are worth it. Also, the API isn't super
ergonomic compared to say javascript (there are no selectors), but it
works well enough so far.

I have not run this through rigorous benchmarking, but it does have a
very noticeable performance improvement, especially in a debug build.

I expect in the future that we'll want to expose some kind of
integration with extensions so they have access to this tree structure
(or some kind of tree structure).

Closes https://github.com/rust-lang/mdBook/issues/1736
2025-09-16 20:26:35 -07:00

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//! Tests for special markdown rendering.
use crate::prelude::*;
use snapbox::file;
// Checks custom header id and classes.
#[test]
fn custom_header_attributes() {
BookTest::from_dir("markdown/custom_header_attributes")
.check_main_file("book/custom_header_attributes.html", str![[r##"
<h1 id="attrs"><a class="header" href="#attrs">Heading Attributes</a></h1>
<h2 class="class1 class2" id="heading-with-classes"><a class="header" href="#heading-with-classes">Heading with classes</a></h2>
<h2 id="both" class="class1 class2"><a class="header" href="#both">Heading with id and classes</a></h2>
<h2 myattr="" otherattr="value" id="myh3" class="myclass1 myclass2"><a class="header" href="#myh3">Heading with attribute</a></h2>
"##]]);
}
// Test for a variety of footnote renderings.
#[test]
fn footnotes() {
BookTest::from_dir("markdown/footnotes")
.run("build", |cmd| {
cmd.expect_stderr(str![[r#"
INFO Book building has started
INFO Running the html backend
WARN footnote `multiple-definitions` in footnotes.md defined multiple times - not updating to new definition
WARN footnote `unused` in `footnotes.md` is defined but not referenced
INFO HTML book written to `[ROOT]/book`
"#]]);
})
.check_main_file(
"book/footnotes.html",
file!["markdown/footnotes/expected/footnotes.html"],
);
}
// Basic table test.
#[test]
fn tables() {
BookTest::from_dir("markdown/tables").check_main_file(
"book/tables.html",
str![[r##"
<h1 id="tables"><a class="header" href="#tables">Tables</a></h1>
<div class="table-wrapper">
<table>
<thead>
<tr><th>foo</th><th>bar</th></tr>
</thead>
<tbody>
<tr><td>baz</td><td>bim</td></tr>
<tr><td>Backslash in code</td><td><code>/</code></td></tr>
<tr><td>Double back in code</td><td><code>//</code></td></tr>
<tr><td>Pipe in code</td><td><code>|</code></td></tr>
<tr><td>Pipe in code2</td><td><code>test | inside</code></td></tr>
</tbody>
</table>
</div>
<div class="table-wrapper">
<table>
<thead>
<tr><th>Neither</th><th style="text-align: left">Left</th><th style="text-align: center">Center</th><th style="text-align: right">Right</th></tr>
</thead>
<tbody>
<tr><td>one</td><td style="text-align: left">two</td><td style="text-align: center">three</td><td style="text-align: right">four</td></tr>
</tbody>
</table>
</div>
"##]],
);
}
// Strikethrough test.
#[test]
fn strikethrough() {
BookTest::from_dir("markdown/strikethrough").check_main_file(
"book/strikethrough.html",
str![[r##"
<h1 id="strikethrough"><a class="header" href="#strikethrough">Strikethrough</a></h1>
<p><del>strikethrough example</del></p>
"##]],
);
}
// Tasklist test.
#[test]
fn tasklists() {
BookTest::from_dir("markdown/tasklists").check_main_file(
"book/tasklists.html",
str![[r##"
<h2 id="tasklisks"><a class="header" href="#tasklisks">Tasklisks</a></h2>
<ul>
<li><input disabled="" type="checkbox" checked=""> Apples</li>
<li><input disabled="" type="checkbox" checked=""> Broccoli</li>
<li><input disabled="" type="checkbox"> Carrots</li>
</ul>
"##]],
);
}
// Smart punctuation test.
#[test]
fn smart_punctuation() {
BookTest::from_dir("markdown/smart_punctuation")
// Default is on.
.check_main_file(
"book/smart_punctuation.html",
str![[r##"
<h1 id="smart-punctuation"><a class="header" href="#smart-punctuation">Smart Punctuation</a></h1>
<ul>
<li>En dash: </li>
<li>Em dash: —</li>
<li>Ellipsis: …</li>
<li>Double quote: “quote”</li>
<li>Single quote: quote</li>
<li>Quote in <code>"code"</code></li>
</ul>
<pre><code>"quoted"
</code></pre>
"##]],
)
.run("build", |cmd| {
cmd.env("MDBOOK_OUTPUT__HTML__SMART_PUNCTUATION", "false");
})
.check_main_file(
"book/smart_punctuation.html",
str![[r##"
<h1 id="smart-punctuation"><a class="header" href="#smart-punctuation">Smart Punctuation</a></h1>
<ul>
<li>En dash: --</li>
<li>Em dash: ---</li>
<li>Ellipsis: ...</li>
<li>Double quote: "quote"</li>
<li>Single quote: 'quote'</li>
<li>Quote in <code>"code"</code></li>
</ul>
<pre><code>"quoted"
</code></pre>
"##]],
);
}
// Basic markdown syntax.
// This doesn't try to cover the commonmark test suite, but maybe it could some day?
#[test]
fn basic_markdown() {
BookTest::from_dir("markdown/basic_markdown").check_all_main_files();
}