From 5b7101ae713cd2a3a69189b8b06eca3d277018bb Mon Sep 17 00:00:00 2001
From: ExE Boss <3889017+ExE-Boss@users.noreply.github.com>
Date: Fri, 18 Apr 2025 01:04:35 +0200
Subject: [PATCH] =?UTF-8?q?Add=C2=A0more=C2=A0tests=20for=C2=A0`Object.pro?=
 =?UTF-8?q?totype.[[SetPrototypeOf]]`=20(#4446)?=
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---
 ...peOf-with-non-circular-values-__proto__.js | 33 +++++++++++++++++++
 ...setPrototypeOf-with-non-circular-values.js | 33 +++++++++++++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values-__proto__.js
 create mode 100644 test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values.js

diff --git a/test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values-__proto__.js b/test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values-__proto__.js
new file mode 100644
index 0000000000..8f8b690202
--- /dev/null
+++ b/test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values-__proto__.js
@@ -0,0 +1,33 @@
+// Copyright (C) 2025 ExE Boss. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-immutable-prototype-exotic-objects-setprototypeof-v
+description: >
+  Object.prototype's [[SetPrototypeOf]] returns false even in cases where
+  OrdinarySetPrototypeOf(O, V) would return true
+info: |
+  9.4.7.1 [[SetPrototypeOf]] (V)
+
+  ...
+  2. Let current be the value of the [[Prototype]] internal slot of O.
+  3. If SameValue(V, current), return true.
+  4. Return false.
+
+  19.1.3 Properties of the Object Prototype Object
+
+  The value of the [[Prototype]] internal slot of the Object prototype object is
+  null and the initial value of the [[Extensible]] internal slot is true.
+features: [Reflect.setPrototypeOf]
+---*/
+
+var ObjProto = Object.prototype;
+
+assert.throws(TypeError, function() {
+  Object.setPrototypeOf(ObjProto, { __proto__: null });
+}, "Object.setPrototypeOf(ObjProto, { __proto__: null }) throws a TypeError");
+
+assert.sameValue(
+  Reflect.setPrototypeOf(ObjProto, { __proto__: null }),
+  false,
+  "Reflect.setPrototypeOf(ObjProto, { __proto__: null }) returns false"
+);
diff --git a/test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values.js b/test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values.js
new file mode 100644
index 0000000000..279d5ab6da
--- /dev/null
+++ b/test/built-ins/Object/prototype/setPrototypeOf-with-non-circular-values.js
@@ -0,0 +1,33 @@
+// Copyright (C) 2025 ExE Boss. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-immutable-prototype-exotic-objects-setprototypeof-v
+description: >
+  Object.prototype's [[SetPrototypeOf]] returns false even in cases where
+  OrdinarySetPrototypeOf(O, V) would return true
+info: |
+  9.4.7.1 [[SetPrototypeOf]] (V)
+
+  ...
+  2. Let current be the value of the [[Prototype]] internal slot of O.
+  3. If SameValue(V, current), return true.
+  4. Return false.
+
+  19.1.3 Properties of the Object Prototype Object
+
+  The value of the [[Prototype]] internal slot of the Object prototype object is
+  null and the initial value of the [[Extensible]] internal slot is true.
+features: [Reflect.setPrototypeOf]
+---*/
+
+var ObjProto = Object.prototype;
+
+assert.throws(TypeError, function() {
+  Object.setPrototypeOf(ObjProto, Object.create(null));
+}, "Object.setPrototypeOf(ObjProto, Object.create(null)) throws a TypeError");
+
+assert.sameValue(
+  Reflect.setPrototypeOf(ObjProto, Object.create(null)),
+  false,
+  "Reflect.setPrototypeOf(ObjProto, Object.create(null)) returns false"
+);