test(js client): pin stop() interrupts reconnect backoff sleep

Regression guard for the setTimeout leak: for each class point at a
refused-connect URL (ws://127.0.0.1:1), start the reconnect loop, wait
50ms for the first serveOneSession to fail and the backoff sleep to
begin, then call stop() and assert elapsed < 500ms. Baseline before
the fix blocks ≈1000ms on the first backoff. Mutation-verified —
neutering the sleep canceller fails all three.

Author: Zawwarsami16

js/package.json

@@ -26,7 +26,7 @@
   ],
   "scripts": {
     "build": "tsc -p tsconfig.json",
-    "test": "tsc -p tsconfig.test.json && node --test dist-test/test/manifest.test.js dist-test/test/manifest_mcp.test.js dist-test/test/protocol.test.js dist-test/test/client.test.js dist-test/test/client_url.test.js dist-test/test/client_lifecycle.test.js dist-test/test/client_stream.test.js dist-test/test/client_handle_chat.test.js dist-test/test/expose.test.js dist-test/test/client_nonerror_throw.test.js"
+    "test": "tsc -p tsconfig.test.json && node --test dist-test/test/manifest.test.js dist-test/test/manifest_mcp.test.js dist-test/test/protocol.test.js dist-test/test/client.test.js dist-test/test/client_url.test.js dist-test/test/client_lifecycle.test.js dist-test/test/client_stream.test.js dist-test/test/client_handle_chat.test.js dist-test/test/expose.test.js dist-test/test/client_nonerror_throw.test.js dist-test/test/client_reconnect_stop.test.js"
   },
   "dependencies": {
     "ws": "^8.18.0"

js/test/client_reconnect_stop.test.ts

@@ -0,0 +1,94 @@
+/**
+ * stop() must interrupt the reconnect-loop backoff sleep — parity with
+ * Python's `asyncio.wait_for(stop_event.wait(), timeout=backoff)`.
+ *
+ * The pre-fix loop slept via `setTimeout(resolve, backoff * 1000)` which
+ * is not cancellable — stop() flipped the `stopped` flag and resolved
+ * runForever(), but the setTimeout kept a Node event-loop reference for
+ * up to 60s, blocking a clean process exit. Also, `stop()` did not await
+ * the internal reconnect task, so callers had no way to observe the loop
+ * had actually wound down.
+ *
+ * Repro strategy: point each class at ws://127.0.0.1:1 (refused instantly);
+ * start() → serveOneSession fails → backoff sleep begins → stop() during
+ * the sleep must return within a small window. Baseline before the fix
+ * blocked ≈1000 ms (the first backoff interval); this test allows 500 ms.
+ */
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import { ZhubPublication, ZhubConnection, ZhubExposure } from '../src/client.js';
+import type { Manifest } from '../src/manifest.js';
+
+function fakeManifest(name: string): Manifest {
+  return {
+    schema_version: '0.1',
+    name,
+    description: '',
+    operator: '',
+    capabilities: [],
+    auth: { type: 'bearer' },
+    rate_limit: '60/min',
+    public: false,
+    contact: '',
+    extensions: {},
+  };
+}
+
+const DEAD_URL = 'ws://127.0.0.1:1';
+
+async function letBackoffBegin(): Promise<void> {
+  // Give the reconnect loop a beat to fail its first serveOneSession and
+  // enter the sleep(). The refuse happens on the next tick; 50ms is plenty.
+  await new Promise((r) => setTimeout(r, 50));
+}
+
+describe('ZhubPublication.stop() interrupts reconnect backoff sleep', () => {
+  it('resolves promptly during backoff, not after full sleep', async () => {
+    const pub = new ZhubPublication(
+      { name: 'p', description: '', hubUrl: DEAD_URL, chatHandler: () => '' },
+      fakeManifest('p'),
+    );
+    pub.start();
+    await letBackoffBegin();
+    const start = Date.now();
+    await pub.stop();
+    const elapsed = Date.now() - start;
+    assert(
+      elapsed < 500,
+      `stop() blocked for ${elapsed} ms — expected < 500 ms (interruptible sleep)`,
+    );
+  });
+});
+
+describe('ZhubConnection.stop() interrupts reconnect backoff sleep', () => {
+  it('resolves promptly during backoff, not after full sleep', async () => {
+    const conn = new ZhubConnection({ aiName: 'a', apiKey: 'zk_test', hubUrl: DEAD_URL });
+    conn.start();
+    await letBackoffBegin();
+    const start = Date.now();
+    await conn.stop();
+    const elapsed = Date.now() - start;
+    assert(
+      elapsed < 500,
+      `stop() blocked for ${elapsed} ms — expected < 500 ms (interruptible sleep)`,
+    );
+  });
+});
+
+describe('ZhubExposure.stop() interrupts reconnect backoff sleep', () => {
+  it('resolves promptly during backoff, not after full sleep', async () => {
+    const exp = new ZhubExposure(
+      { name: 'e', description: '', hubUrl: DEAD_URL, capabilities: {} },
+      fakeManifest('e'),
+    );
+    exp.start();
+    await letBackoffBegin();
+    const start = Date.now();
+    await exp.stop();
+    const elapsed = Date.now() - start;
+    assert(
+      elapsed < 500,
+      `stop() blocked for ${elapsed} ms — expected < 500 ms (interruptible sleep)`,
+    );
+  });
+});