diff --git a/README.md b/README.md
index 0407239..563e158 100644
--- a/README.md
+++ b/README.md
@@ -279,8 +279,8 @@ top level of the file's TAP output.
 
 The second `setImmediate()` creates an `uncaughtException` event.
 `uncaughtException` and `unhandledRejection` events originating from a completed
-test are handled by the `test` module and reported as diagnostic warnings in
-the top level of the file's TAP output.
+test are marked as failed by the `test` module and reported as diagnostic
+warnings in the top level of the file's TAP output.
 
 ```js
 test('a test that creates asynchronous activity', t => {
diff --git a/lib/internal/test_runner/harness.js b/lib/internal/test_runner/harness.js
index bddfedc..26d35ba 100644
--- a/lib/internal/test_runner/harness.js
+++ b/lib/internal/test_runner/harness.js
@@ -1,4 +1,4 @@
-// https://github.com/nodejs/node/blob/59527de13d39327eb3dfa8dedc92241eb40066d5/lib/internal/test_runner/harness.js
+// https://github.com/nodejs/node/blob/06603c44a5b0e92b1a3591ace467ce9770bf9658/lib/internal/test_runner/harness.js
 'use strict'
 const {
   ArrayPrototypeForEach,
@@ -47,6 +47,7 @@ function createProcessEventHandler (eventName, rootTest) {
         `triggered an ${eventName} event.`
 
       rootTest.diagnostic(msg)
+      process.exitCode = 1
       return
     }
 
diff --git a/test/fixtures/test-runner/extraneous_set_immediate_async.mjs b/test/fixtures/test-runner/extraneous_set_immediate_async.mjs
new file mode 100644
index 0000000..241e262
--- /dev/null
+++ b/test/fixtures/test-runner/extraneous_set_immediate_async.mjs
@@ -0,0 +1,6 @@
+// https://github.com/nodejs/node/blob/06603c44a5b0e92b1a3591ace467ce9770bf9658/test/fixtures/test-runner/extraneous_set_immediate_async.mjs
+import test from '#node:test'
+
+test('extraneous async activity test', () => {
+  setImmediate(() => { throw new Error() })
+})
diff --git a/test/fixtures/test-runner/extraneous_set_timeout_async.mjs b/test/fixtures/test-runner/extraneous_set_timeout_async.mjs
new file mode 100644
index 0000000..2b5ee72
--- /dev/null
+++ b/test/fixtures/test-runner/extraneous_set_timeout_async.mjs
@@ -0,0 +1,6 @@
+// https://github.com/nodejs/node/blob/06603c44a5b0e92b1a3591ace467ce9770bf9658/test/fixtures/test-runner/extraneous_set_timeout_async.mjs
+import test from '#node:test'
+
+test('extraneous async activity test', () => {
+  setTimeout(() => { throw new Error() }, 100)
+})
diff --git a/test/parallel/test-runner-extraneous-async-activity.js b/test/parallel/test-runner-extraneous-async-activity.js
new file mode 100644
index 0000000..da826c4
--- /dev/null
+++ b/test/parallel/test-runner-extraneous-async-activity.js
@@ -0,0 +1,32 @@
+// https://github.com/nodejs/node/blob/06603c44a5b0e92b1a3591ace467ce9770bf9658/test/parallel/test-runner-extraneous-async-activity.js
+'use strict'
+require('../common')
+const fixtures = require('../common/fixtures')
+const assert = require('assert')
+const { spawnSync } = require('child_process')
+
+{
+  const child = spawnSync(process.execPath, [
+    '--test',
+    fixtures.path('test-runner', 'extraneous_set_immediate_async.mjs')
+  ])
+  const stdout = child.stdout.toString()
+  assert.match(stdout, /^# pass 0$/m)
+  assert.match(stdout, /^# fail 1$/m)
+  assert.match(stdout, /^# cancelled 0$/m)
+  assert.strictEqual(child.status, 1)
+  assert.strictEqual(child.signal, null)
+}
+
+{
+  const child = spawnSync(process.execPath, [
+    '--test',
+    fixtures.path('test-runner', 'extraneous_set_timeout_async.mjs')
+  ])
+  const stdout = child.stdout.toString()
+  assert.match(stdout, /^# pass 0$/m)
+  assert.match(stdout, /^# fail 1$/m)
+  assert.match(stdout, /^# cancelled 0$/m)
+  assert.strictEqual(child.status, 1)
+  assert.strictEqual(child.signal, null)
+}