From 7c09583eaa5ebdc87787c3f1cbbdaa3f44e9d47b Mon Sep 17 00:00:00 2001
From: Divyansh Singh <40380293+brc-dd@users.noreply.github.com>
Date: Fri, 24 Jul 2026 01:28:24 +0530
Subject: [PATCH] test(markdown): cover attrs behavior before plugin migration

Captures what the markdown-it-attrs patch enforces (curly attributes
never consume fence info, preserving line-highlight syntax) plus the
supported attribute placements, as a regression baseline.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 __tests__/unit/node/markdown/markdown.test.ts | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/__tests__/unit/node/markdown/markdown.test.ts b/__tests__/unit/node/markdown/markdown.test.ts
index 0c8e554d5..d46c5aadf 100644
--- a/__tests__/unit/node/markdown/markdown.test.ts
+++ b/__tests__/unit/node/markdown/markdown.test.ts
@@ -114,6 +114,31 @@ describe('node/markdown/markdown', () => {
     })
   })
 
+  describe('attrs', () => {
+    test('does not consume fence info', async () => {
+      // line-highlight / meta syntax must reach the highlighter untouched
+      const meta = await render('```js{4}\nconst a = 1\n```')
+      expect(meta).toContain('language-js')
+      expect(meta).not.toContain('4=""')
+
+      // curly attributes have no effect on fenced code blocks
+      const backtick = await render('```js {.foo}\nconst a = 1\n```')
+      expect(backtick).not.toContain('class="foo"')
+      const tilde = await render('~~~js {.foo}\nconst a = 1\n~~~')
+      expect(tilde).not.toContain('class="foo"')
+    })
+
+    test('applies to inline elements and blocks', async () => {
+      expect(await render('*hi*{.cls}')).toContain('<em class="cls">')
+      expect(await render('`code`{.cls}')).toContain('class="cls"')
+      expect(await render('text {.cls}')).toContain('<p class="cls">')
+      expect(await render('- item\n{.cls}')).toContain('<ul class="cls">')
+      expect(await render('| a |\n| --- |\n| b |\n\n{.cls}')).toContain(
+        '<table class="cls"'
+      )
+    })
+  })
+
   // attrs applies at a fixed position in the core chain (before linkify),
   // while anchor pushes to its end, so anchor always sees user-defined ids
   // no matter which plugin is registered first