Use native Chrome for Reddit login handoff

tests/native-login-gate.test.ts

@@ -0,0 +1,36 @@
+import type { AddressInfo } from 'node:net';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { createNativeLoginGate } from '../src/native-login-gate.js';
+
+const servers: Array<ReturnType<typeof createNativeLoginGate>> = [];
+
+afterEach(async () => {
+  await Promise.all(servers.splice(0).map((server) => new Promise<void>((resolve) => {
+    server.close(() => resolve());
+  })));
+});
+
+describe('native Reddit login gate', () => {
+  it('serves VNC guidance and completes only after the explicit handoff', async () => {
+    const onComplete = vi.fn();
+    const server = createNativeLoginGate({
+      publicVncUrl: 'https://red-vnc.example/vnc.html',
+      onComplete,
+    }).listen(0);
+    servers.push(server);
+    await new Promise<void>((resolve) => server.once('listening', resolve));
+    const { port } = server.address() as AddressInfo;
+
+    const page = await fetch(`http://127.0.0.1:${port}/`);
+    const html = await page.text();
+    expect(html).toContain('Chrome is running without automation');
+    expect(html).toContain('https://red-vnc.example/vnc.html');
+    expect(html).toContain("fetch('/complete', { method: 'POST' })");
+    expect(onComplete).not.toHaveBeenCalled();
+
+    const completed = await fetch(`http://127.0.0.1:${port}/complete`, { method: 'POST' });
+    expect(completed.status).toBe(202);
+    expect(await completed.json()).toEqual({ ok: true, restarting: true });
+    expect(onComplete).toHaveBeenCalledOnce();
+  });
+});