Import wpt@357b83b809e3cbc7a1805e7c3ca108a7980d782f

third_party/WebKit/LayoutTests/imported/wpt/dom/collections/HTMLCollection-supported-property-names.html

Index: third_party/WebKit/LayoutTests/imported/wpt/dom/collections/HTMLCollection-supported-property-names.html
diff --git a/third_party/WebKit/LayoutTests/imported/wpt/dom/collections/HTMLCollection-supported-property-names.html b/third_party/WebKit/LayoutTests/imported/wpt/dom/collections/HTMLCollection-supported-property-names.html
index a37163b7d189c292336f17a5db8ba3c0ac512efa..0a9df1ad6606476c3f3463032957cec931af19b4 100644
--- a/third_party/WebKit/LayoutTests/imported/wpt/dom/collections/HTMLCollection-supported-property-names.html
+++ b/third_party/WebKit/LayoutTests/imported/wpt/dom/collections/HTMLCollection-supported-property-names.html
@@ -51,4 +51,85 @@ test(function () {
 
   assert_array_equals(Object.getOwnPropertyNames(elements), ['0', 'someProperty']);
 }, 'Object.getOwnPropertyNames on HTMLCollection with expando object');
+
+test(function() {
+  var elements = document.getElementsByTagName("span");
+  var old_item = elements["some-id"];
+  var old_desc = Object.getOwnPropertyDescriptor(elements, "some-id");
+  assert_equals(old_desc.value, old_item);
+  assert_false(old_desc.enumerable);
+  assert_true(old_desc.configurable);
+  assert_false(old_desc.writable);
+
+  elements["some-id"] = 5;
+  assert_equals(elements["some-id"], old_item);
+  assert_throws(new TypeError(), function() {
+    "use strict";
+    elements["some-id"] = 5;
+  });
+  assert_throws(new TypeError(), function() {
+    Object.defineProperty(elements, "some-id", { value: 5 });
+  });
+
+  delete elements["some-id"];
+  assert_equals(elements["some-id"], old_item);
+
+  assert_throws(new TypeError(), function() {
+    "use strict";
+    delete elements["some-id"];
+  });
+  assert_equals(elements["some-id"], old_item);
+
+}, 'Trying to set an expando that would shadow an already-existing named property');
+
+test(function() {
+  var elements = document.getElementsByTagName("span");
+  var old_item = elements["new-id"];
+  var old_desc = Object.getOwnPropertyDescriptor(elements, "new-id");
+  assert_equals(old_item, undefined);
+  assert_equals(old_desc, undefined);
+
+  elements["new-id"] = 5;
+  assert_equals(elements["new-id"], 5);
+
+  var span = document.createElement("span");
+  this.add_cleanup(function () {span.remove();});
+  span.id = "new-id";
+  document.body.appendChild(span);
+
+  assert_equals(elements.namedItem("new-id"), span);
+  assert_equals(elements["new-id"], 5);
+
+  delete elements["new-id"];
+  assert_equals(elements["new-id"], span);
+}, 'Trying to set an expando that shadows a named property that gets added later');
+
+test(function() {
+  var elements = document.getElementsByTagName("span");
+  var old_item = elements["new-id2"];
+  var old_desc = Object.getOwnPropertyDescriptor(elements, "new-id2");
+  assert_equals(old_item, undefined);
+  assert_equals(old_desc, undefined);
+
+  Object.defineProperty(elements, "new-id2", { configurable: false, writable:
+                                              false, value: 5 });
+  assert_equals(elements["new-id2"], 5);
+
+  var span = document.createElement("span");
+  this.add_cleanup(function () {span.remove();});
+  span.id = "new-id2";
+  document.body.appendChild(span);
+
+  assert_equals(elements.namedItem("new-id2"), span);
+  assert_equals(elements["new-id2"], 5);
+
+  delete elements["new-id2"];
+  assert_equals(elements["new-id2"], 5);
+
+  assert_throws(new TypeError(), function() {
+    "use strict";
+    delete elements["new-id2"];
+  });
+  assert_equals(elements["new-id2"], 5);
+}, 'Trying to set a non-configurable expando that shadows a named property that gets added later');
 </script>