refactor(launcher): consolidate mpv socket readiness primitive

launcher/mpv.test.ts

@@ -0,0 +1,61 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import path from 'node:path';
+import net from 'node:net';
+import { EventEmitter } from 'node:events';
+import { waitForUnixSocketReady } from './mpv';
+import * as mpvModule from './mpv';
+
+function createTempSocketPath(): { dir: string; socketPath: string } {
+  const baseDir = path.join(process.cwd(), '.tmp', 'launcher-mpv-tests');
+  fs.mkdirSync(baseDir, { recursive: true });
+  const dir = fs.mkdtempSync(path.join(baseDir, 'case-'));
+  return { dir, socketPath: path.join(dir, 'mpv.sock') };
+}
+
+test('mpv module exposes only canonical socket readiness helper', () => {
+  assert.equal('waitForSocket' in mpvModule, false);
+});
+
+test('waitForUnixSocketReady returns false when socket never appears', async () => {
+  const { dir, socketPath } = createTempSocketPath();
+  try {
+    const ready = await waitForUnixSocketReady(socketPath, 120);
+    assert.equal(ready, false);
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test('waitForUnixSocketReady returns false when path exists but is not socket', async () => {
+  const { dir, socketPath } = createTempSocketPath();
+  try {
+    fs.writeFileSync(socketPath, 'not-a-socket');
+    const ready = await waitForUnixSocketReady(socketPath, 200);
+    assert.equal(ready, false);
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test('waitForUnixSocketReady returns true when socket becomes connectable before timeout', async () => {
+  const { dir, socketPath } = createTempSocketPath();
+  fs.writeFileSync(socketPath, '');
+  const originalCreateConnection = net.createConnection;
+  try {
+    net.createConnection = (() => {
+      const socket = new EventEmitter() as net.Socket;
+      socket.destroy = (() => socket) as net.Socket['destroy'];
+      socket.setTimeout = (() => socket) as net.Socket['setTimeout'];
+      setTimeout(() => socket.emit('connect'), 25);
+      return socket;
+    }) as typeof net.createConnection;
+
+    const ready = await waitForUnixSocketReady(socketPath, 400);
+    assert.equal(ready, true);
+  } finally {
+    net.createConnection = originalCreateConnection;
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});