Implement Proxy object [[Delete]] internal method (#3616)

The algorithm is based on ECMA-262 v6, 9.5.10

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

tests/jerry/es2015/proxy_delete.js

@@ -12,7 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// TODO: Update these tests when the internal routine has been implemented
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
 var target = {};
 var handler = { deleteProperty (target) {
@@ -39,7 +41,128 @@ try {
 
 try {
   // 22.1.3.16.6.e
-  Array.prototype.pop.call(proxy)
+  Array.prototype.pop.call(proxy);
+  assert(false);
+} catch (e) {
+  assert(e === 42);
+}
+
+// test basic functionality
+var target = {foo: "bar"};
+var handler = {
+  deleteProperty(obj, prop) {
+    delete obj[prop];
+  }
+}
+
+var proxy = new Proxy(target, handler);
+
+assert(target.foo === "bar")
+assert(proxy.foo === "bar");
+
+assert(delete proxy.foo === false);
+
+assert(target.foo === undefined);
+assert(proxy.foo === undefined);
+
+assert(target.bar === undefined);
+assert(delete proxy.bar == false);
+assert(target.bar === undefined);
+
+var handler2 = {
+  deleteProperty(obj, prop) {
+    delete obj[prop];
+    return true;
+  }
+}
+
+var proxy = new Proxy(target, handler2);
+
+assert(target.bar === undefined);
+assert(delete proxy.bar == true);
+assert(target.bar === undefined);
+
+// test with no trap
+var target = {1: 42};
+var handler = {};
+var proxy = new Proxy(target, handler);
+
+assert(target[1] === 42)
+assert(delete proxy[1] === true)
+assert(target[1] === undefined);
+
+// test with undefined trap
+var target = {2: 52};
+var handler = { deleteProperty: null};
+var proxy = new Proxy(target, handler);
+
+assert(target[2] === 52)
+assert(delete proxy[2] === true)
+assert(target[2] === undefined);
+
+// test when trap is invalid
+var target = {};
+var handler = { deleteProperty: true };
+var proxy = new Proxy(target, handler);
+
+try {
+  delete proxy[0];
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError);
+}
+
+// test when handler is null
+var revocable = Proxy.revocable ({}, {});
+var proxy = revocable.proxy;
+revocable.revoke();
+
+try {
+  delete proxy.foo;
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError);
+}
+
+// test when target is proxy
+var target = {prop: "foo"};
+var handler = {
+  deleteProperty(obj, prop) {
+    delete obj[prop];
+  }
+};
+
+var proxy1 = new Proxy(target, handler);
+var proxy2 = new Proxy(proxy1, handler);
+
+assert(target.prop === "foo");
+assert(proxy1.prop === "foo");
+assert(proxy2.prop === "foo");
+
+delete proxy2.prop;
+
+assert(target.prop === undefined);
+assert(proxy1.prop === undefined);
+assert(proxy2.prop === undefined);
+
+// tests when invariants gets violated
+var target = {};
+var handler = {
+  deleteProperty(obj, prop) {
+    delete obj[prop];
+    return true;
+  }
+};
+
+Object.defineProperty(target, "foo", {
+  configurable: false,
+  value: "foo"
+});
+
+var proxy = new Proxy (target, handler);
+
+try {
+  delete proxy.foo;
   assert(false);
 } catch (e) {
   assert(e instanceof TypeError);