Add tests for Proxy semantics change (#2143)

* Add not extensible target test for `deleteProperty`

* Add non-writable descriptor test for `defineProperty`

* Add non-writable descriptor test for `getOwnPropertyDescriptor`

test/built-ins/Proxy/defineProperty/targetdesc-not-configurable-writable-desc-not-writable.js

@@ -0,0 +1,40 @@
+// Copyright (C) 2019 Aleksey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+description: >
+    Throw a TypeError exception if trap result is true, targetDesc is not configurable
+    and writable, while Desc is not writable.
+info: |
+    [[DefineOwnProperty]] (P, Desc)
+
+    ...
+    16. Else targetDesc is not undefined,
+        ...
+        c. If IsDataDescriptor(targetDesc) is true, targetDesc.[[Configurable]] is
+        false, and targetDesc.[[Writable]] is true, then
+            i. If Desc has a [[Writable]] field and Desc.[[Writable]] is
+            false, throw a TypeError exception.
+    ...
+features: [Proxy, Reflect]
+---*/
+
+var trapCalls = 0;
+var p = new Proxy({}, {
+  defineProperty: function(t, prop, desc) {
+    Object.defineProperty(t, prop, {
+      configurable: false,
+      writable: true,
+    });
+
+    trapCalls++;
+    return true;
+  },
+});
+
+assert.throws(TypeError, function() {
+  Reflect.defineProperty(p, "prop", {
+    writable: false,
+  });
+});
+assert.sameValue(trapCalls, 1);

test/built-ins/Proxy/deleteProperty/targetdesc-is-configurable-target-is-not-extensible.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Aleksey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-proxy-object-internal-methods-and-internal-slots-delete-p
+description: >
+    Throw a TypeError exception if trap result is true, targetDesc is configurable,
+    and target is not extensible.
+info: |
+    [[Delete]] (P)
+
+    ...
+    13. Let extensibleTarget be ? IsExtensible(target).
+    14. If extensibleTarget is false, throw a TypeError exception.
+    ...
+features: [Proxy, Reflect]
+---*/
+
+var trapCalls = 0;
+var p = new Proxy({prop: 1}, {
+  deleteProperty: function(t, prop) {
+    Object.preventExtensions(t);
+    trapCalls++;
+    return true;
+  },
+});
+
+assert.throws(TypeError, function() {
+  Reflect.deleteProperty(p, "prop");
+});
+assert.sameValue(trapCalls, 1);
+
+assert(Reflect.deleteProperty(p, "nonExistent"));
+assert.sameValue(trapCalls, 2);

test/built-ins/Proxy/getOwnPropertyDescriptor/resultdesc-is-not-configurable-not-writable-targetdesc-is-writable.js

@@ -0,0 +1,40 @@
+// Copyright (C) 2019 Aleksey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p
+description: >
+    Throws a TypeError exception if resultDesc is both non-configurable and
+    non-writable, while targetDesc is writable.
+info: |
+    [[GetOwnProperty]] (P)
+
+    ...
+    17. If resultDesc.[[Configurable]] is false, then
+        ...
+        b. If resultDesc has a [[Writable]] field and resultDesc.[[Writable]] is
+        false, then
+            i. If targetDesc.[[Writable]] is true, throw a TypeError exception.
+    ...
+features: [Proxy]
+---*/
+
+var trapCalls = 0;
+var p = new Proxy({}, {
+  getOwnPropertyDescriptor: function(t, prop) {
+    Object.defineProperty(t, prop, {
+      configurable: false,
+      writable: true,
+    });
+
+    trapCalls++;
+    return {
+      configurable: false,
+      writable: false,
+    };
+  },
+});
+
+assert.throws(TypeError, function() {
+  Object.getOwnPropertyDescriptor(p, "prop");
+});
+assert.sameValue(trapCalls, 1);