From 81d55bf2d6e43f34e5ed281248caa721878e6e56 Mon Sep 17 00:00:00 2001
From: Moshe Atlow <moshe@atlow.co.il>
Date: Wed, 28 Jan 2026 19:29:10 +0200
Subject: [PATCH] test_runner: fix passing `expectFailure`

---
 lib/internal/test_runner/test.js               |  9 +++++++++
 .../test-runner-expect-error-but-pass.js       | 18 ++++++++++++++++++
 test/parallel/test-runner-expect-error.js      | 15 +++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 test/parallel/test-runner-expect-error-but-pass.js
 create mode 100644 test/parallel/test-runner-expect-error.js

diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index e426438faba75f..beeb49c1763473 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -82,6 +82,7 @@ const kParentAlreadyFinished = 'parentAlreadyFinished';
 const kSubtestsFailed = 'subtestsFailed';
 const kTestCodeFailure = 'testCodeFailure';
 const kTestTimeoutFailure = 'testTimeoutFailure';
+const kExpectedFailure = 'expectedFailure';
 const kHookFailure = 'hookFailed';
 const kDefaultTimeout = null;
 const noop = FunctionPrototype;
@@ -957,6 +958,14 @@ class Test extends AsyncResource {
   }
 
   pass() {
+    if (this.error == null && this.expectFailure === true && !this.skipped) {
+      this.passed = false;
+      this.error = new ERR_TEST_FAILURE(
+        'test was expected to fail but passed',
+        kExpectedFailure,
+      );
+      return;
+    }
     if (this.error !== null) {
       return;
     }
diff --git a/test/parallel/test-runner-expect-error-but-pass.js b/test/parallel/test-runner-expect-error-but-pass.js
new file mode 100644
index 00000000000000..b6900724fa8dbe
--- /dev/null
+++ b/test/parallel/test-runner-expect-error-but-pass.js
@@ -0,0 +1,18 @@
+'use strict';
+const common = require('../common');
+const assert = require('node:assert');
+const { run, test } = require('node:test');
+
+if (!process.env.NODE_TEST_CONTEXT) {
+  const stream = run({ files: [__filename] });
+
+  stream.on('test:pass', common.mustNotCall());
+  stream.on('test:fail', common.mustCall((event) => {
+    assert.strictEqual(event.expectFailure, true);
+    assert.strictEqual(event.details.error.code, 'ERR_TEST_FAILURE');
+    assert.strictEqual(event.details.error.failureType, 'expectedFailure');
+    assert.strictEqual(event.details.error.cause, 'test was expected to fail but passed');
+  }, 1));
+} else {
+  test('passing test', { expectFailure: true }, () => {});
+}
diff --git a/test/parallel/test-runner-expect-error.js b/test/parallel/test-runner-expect-error.js
new file mode 100644
index 00000000000000..6185c91df43c26
--- /dev/null
+++ b/test/parallel/test-runner-expect-error.js
@@ -0,0 +1,15 @@
+'use strict';
+const common = require('../common');
+const assert = require('node:assert');
+const { run, test } = require('node:test');
+
+if (!process.env.NODE_TEST_CONTEXT) {
+  const stream = run({ files: [__filename] });
+
+  stream.on('test:fail', common.mustNotCall());
+  stream.on('test:pass', common.mustCall((event) => {
+    assert.strictEqual(event.expectFailure, true);
+  }, 1));
+} else {
+  test('failing test', { expectFailure: true }, () => assert.fail('should not pass'));
+}