mdwn: Automatically detect which libdiscount flags to use

Unconditionally passing arbitrary numbers as flags turns out to be a
bad idea, because some of the "unused" values have historically had
side-effects internal to libdiscount. Detect whether the known flags
work by rendering short Markdown snippets the first time we htmlize,
checking whether each known flag is both necessary and sufficient.

Signed-off-by: Simon McVittie <smcv@debian.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/t/mdwn.t b/t/mdwn.t
index 93b8bd8e9..ca3180139 100755
--- a/t/mdwn.t
+++ b/t/mdwn.t
@@ -8,6 +8,7 @@ BEGIN { use_ok("IkiWiki"); }
 
 %config=IkiWiki::defaultconfig();
 $config{srcdir}=$config{destdir}="/dev/null";
+$config{disable_plugins}=["htmlscrubber"];
 IkiWiki::loadplugins();
 IkiWiki::checkconfig();
 
@@ -41,4 +42,25 @@ like(IkiWiki::htmlize("foo", "foo", "mdwn",
 	"This works[^1]\n\n[^1]: Sometimes it doesn't.\n"),
 	qr{<p>This works<sup\W}, "footnotes can be enabled");
 
+SKIP: {
+	skip 'set $IKIWIKI_TEST_ASSUME_MODERN_DISCOUNT if you have Discount 2.2.0+', 4
+		unless $ENV{IKIWIKI_TEST_ASSUME_MODERN_DISCOUNT};
+	like(IkiWiki::htmlize("foo", "foo", "mdwn",
+			"Definition list\n: A useful HTML structure\n"),
+		qr{<dl>.*<dt>Definition list</dt>\s*<dd>A useful HTML structure</dd>}s,
+		"definition lists are enabled by default");
+	like(IkiWiki::htmlize("foo", "foo", "mdwn",
+			"```\n#!/bin/sh\n```\n"),
+		qr{<pre>\s*<code>\s*[#]!/bin/sh\s*</code>\s*</pre>}s,
+		"code blocks are enabled by default");
+	like(IkiWiki::htmlize("foo", "foo", "mdwn",
+			"<foo_bar>"),
+		qr{<foo_bar>},
+		"GitHub tag name extensions are enabled by default");
+	like(IkiWiki::htmlize("foo", "foo", "mdwn",
+			"<style>foo</style>"),
+		qr{<style>foo</style>},
+		"Styles are not stripped by default");
+}
+
 done_testing();