Keep one long-lived yt-dlp worker process instead of spawning per call

server/ytdlp-pool.test.js

@@ -0,0 +1,44 @@
+import { test, expect } from 'bun:test';
+import { existsSync, readFileSync } from 'node:fs';
+import { createYtdlpPool } from './ytdlp-pool.js';
+
+// The worker imports yt_dlp from the release ZIPAPP (a python script, starts with
+// "#!"). `npm run setup` downloads yt-dlp_linux, a compiled ELF Python can't import,
+// so an ELF (or nothing) means these tests skip.
+const isZipapp = (p) => { try { return readFileSync(p).subarray(0, 2).toString() === '#!'; } catch { return false; } };
+const YTDLP = [process.env.YTDLP_PATH, '../bin/yt-dlp', Bun.which('yt-dlp')].find((p) => p && existsSync(p) && isZipapp(p)) || '';
+const quiet = { warn() {}, info() {} };
+
+test.skipIf(!YTDLP)('runs requests and reports yt-dlp errors without dying', async () => {
+  const pool = createYtdlpPool({ ytdlpPath: YTDLP, size: 1, log: quiet });
+  try {
+    const v = await pool.run(['--version']);
+    expect(v.trim()).toMatch(/^\d{4}\.\d{2}\.\d{2}/);
+    const err = await pool.run(['--definitely-not-a-flag']).catch((e) => e);
+    expect(err).toBeInstanceOf(Error);
+    expect(err.poolInfra).toBeFalsy();
+    expect((await pool.run(['--version'])).trim()).toBe(v.trim());
+  } finally { pool.close(); }
+}, 30000);
+
+test('a broken python disables the pool and rejects as infra', async () => {
+  const pool = createYtdlpPool({ python: '/nonexistent/python3', size: 1, log: quiet });
+  const err = await pool.run(['--version']).catch((e) => e);
+  expect(err.poolInfra).toBe(true);
+  await new Promise((r) => setTimeout(r, 3500));
+  expect(pool.disabled).toBe(true);
+  expect((await pool.run(['--version']).catch((e) => e)).poolInfra).toBe(true);
+  pool.close();
+}, 15000);
+
+test.skipIf(!YTDLP)('workers are replaced after maxRequests and by recycle(), without failing requests', async () => {
+  const pool = createYtdlpPool({ ytdlpPath: YTDLP, size: 1, maxRequests: 1, log: quiet });
+  try {
+    const a = await pool.run(['--version']);
+    const b = await pool.run(['--version']); // served by a fresh worker
+    expect(b).toBe(a);
+    pool.recycle();
+    expect(await pool.run(['--version'])).toBe(a);
+    expect(pool.disabled).toBe(false);
+  } finally { pool.close(); }
+}, 30000);