Index: test/audio-attachment-art.test.js
===================================================================
--- test/audio-attachment-art.test.js	(revision 8cf8b5f1195ab37aa4bc2f5248897f0cb8b5d0b8)
+++ test/audio-attachment-art.test.js	(revision 8cf8b5f1195ab37aa4bc2f5248897f0cb8b5d0b8)
@@ -0,0 +1,49 @@
+// Cover art on federated audio — a fedi_open track's Audio attachment carries the track
+// cover (else the post cover) as an AS2 `icon`, so Mastodon's native audio player can show
+// artwork instead of a blank tile. In-memory SQLite. Run: npm test
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+
+process.env.DATABASE_PATH = ':memory:';
+process.env.PUBLIC_BASE_URL = 'https://test.example';
+
+const dbMod = await import('../src/config/database.js');
+const db = dbMod.default;
+dbMod.initializeDatabase();
+const AP = (await import('../src/services/ActivityPubService.js')).default;
+
+const BASE = 'https://test.example';
+db.prepare('INSERT INTO users (id, username, email, password_hash, role) VALUES (?,?,?,?,?)').run('u1', 'u1', 'u1@test', 'x', 'god');
+db.prepare('INSERT INTO sites (id, slug, title, owner_id, is_primary) VALUES (?,?,?,?,?)').run('s1', 'demo', 'Demo', 'u1', 1);
+const site = db.prepare('SELECT * FROM sites WHERE id = ?').get('s1');
+site.primary_slug = 'demo';
+
+db.prepare('INSERT INTO media (id, site_id, filename, mime_type, size, storage_path) VALUES (?,?,?,?,?,?)')
+  .run('m1', 's1', 'song.mp3', 'audio/mpeg', 1000, '/x/song.mp3');
+db.prepare('INSERT INTO audio_tracks (id, site_id, title, media_id, cover_url, fedi_open) VALUES (?,?,?,?,?,?)')
+  .run('t1', 's1', 'Song One', 'm1', '/media/art.webp', 1);
+db.prepare('INSERT INTO media (id, site_id, filename, mime_type, size, storage_path) VALUES (?,?,?,?,?,?)')
+  .run('m2', 's1', 'bare.mp3', 'audio/mpeg', 1000, '/x/bare.mp3');
+db.prepare('INSERT INTO audio_tracks (id, site_id, title, media_id, fedi_open) VALUES (?,?,?,?,?)')
+  .run('t2', 's1', 'Bare Track', 'm2', 1);
+
+test('a fedi_open track carries its cover as the Audio attachment icon', () => {
+  const post = { id: 'p1', slug: 'x', title: '', content: '<p>[[track:t1]]</p>', tags: '[]', created_at: '2026-01-01T00:00:00Z' };
+  const att = (AP.buildNote(BASE, site, post).attachment || []).find((a) => a.type === 'Audio');
+  assert.ok(att, 'Audio attachment present');
+  assert.ok(att.icon, 'icon present');
+  assert.equal(att.icon.type, 'Image');
+  assert.equal(att.icon.url, `${BASE}/media/art.webp`);
+});
+
+test('a coverless track falls back to the post cover', () => {
+  const post = { id: 'p2', slug: 'y', title: '', content: '<p>[[track:t2]]</p>', tags: '[]', cover_image_url: '/media/post.webp', created_at: '2026-01-01T00:00:00Z' };
+  const att = (AP.buildNote(BASE, site, post).attachment || []).find((a) => a.type === 'Audio');
+  assert.equal(att.icon.url, `${BASE}/media/post.webp`);
+});
+
+test('no track cover and no post cover → no icon', () => {
+  const post = { id: 'p3', slug: 'z', title: '', content: '<p>[[track:t2]]</p>', tags: '[]', created_at: '2026-01-01T00:00:00Z' };
+  const att = (AP.buildNote(BASE, site, post).attachment || []).find((a) => a.type === 'Audio');
+  assert.ok(!('icon' in att));
+});