Clean up browser test pipes and scope deliberate outage errors

test/e2e/client-close.test.js

@@ -0,0 +1,51 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { spawn } from 'node:child_process';
+import { once } from 'node:events';
+import { Client } from './client.mjs';
+
+test('closing an exited browser releases stderr even when a helper inherited its pipe', { timeout: 5000 }, async () => {
+  const child = spawn(process.execPath, ['-e', `
+    const { spawn } = require('node:child_process');
+    const helper = spawn(process.execPath, ['-e', 'setTimeout(() => {}, 5000)'],
+      { stdio: ['ignore', 'ignore', 2], detached: true });
+    helper.unref();
+    process.send({ pid: helper.pid }, () => process.exit(0));
+  `], { stdio: ['ignore', 'pipe', 'pipe', 'ipc'] });
+  const exited = once(child, 'exit');
+  let helperPid;
+  try {
+    [{ pid: helperPid }] = await once(child, 'message');
+    child.stderr.resume();
+    await exited;
+    assert.equal(child.exitCode, 0);
+    assert.equal(child.stderr.destroyed, false, 'the helper still holds the other end of stderr');
+    const client = new Client(null, '', 'cleanup');
+    client.browser = { process: () => child, close: async () => {} };
+    await client.close();
+    assert.equal(child.stderr.destroyed, true, 'the exited browser no longer keeps this test alive');
+  } finally {
+    if (helperPid) { try { process.kill(helperPid, 'SIGTERM'); } catch { /* already exited */ } }
+    for (const stream of child.stdio) stream?.destroy?.();
+    if (child.exitCode == null && child.signalCode == null) child.kill();
+  }
+});
+
+test('a failed shutdown leaves a live browser and its pipes alone', async () => {
+  let destroyed = 0;
+  const child = { exitCode: null, signalCode: null, stdio: [{ destroy: () => destroyed++ }] };
+  const client = new Client(null, '', 'cleanup');
+  client.browser = { process: () => child, close: async () => { throw new Error('not closed'); } };
+  await client.close();
+  assert.equal(destroyed, 0);
+});
+
+test('a browser terminated by a signal releases only its owned pipes; an absent browser is harmless', async () => {
+  let destroyed = 0;
+  const client = new Client(null, '', 'cleanup');
+  await client.close();
+  client.browser = { process: () => ({ exitCode: null, signalCode: 'SIGTERM', stdio: [null, { destroy: () => destroyed++ }] }),
+    close: async () => {} };
+  await client.close();
+  assert.equal(destroyed, 1);
+});

test/e2e/client.mjs

@@ -189,7 +189,15 @@ export class Client {
     throw new Error(`${this.label}: timed out waiting for ${what} (last: ${JSON.stringify(last)})`);
   }
 
-  async close() { await this.browser?.close().catch(() => {}); }
+  async close() {
+    const child = this.browser?.process();
+    await this.browser?.close().catch(() => {});
+    // Chrome's crash/update helpers can inherit stderr after the launched browser exits. Release only our
+    // exited child's pipes; otherwise readline keeps the test alive after all its assertions have finished.
+    if (child && (child.exitCode != null || child.signalCode != null)) {
+      for (const stream of child.stdio) stream?.destroy?.();
+    }
+  }
 
   /** Real mouse click on the `nth` visible, uncovered element matching `sel` whose text includes `text`. */
   async click(sel, text = null, { timeout = 15000, optional = false, nth = 0, button = 'left', any = false } = {}) {