1 files changed, 48 insertions, 0 deletions
diff --git a/testing/web-platform/tests/dom/nodes/MutationObserver-disconnect.html b/testing/web-platform/tests/dom/nodes/MutationObserver-disconnect.html
new file mode 100644
index 0000000000..883edecf74
--- /dev/null
+++ b/testing/web-platform/tests/dom/nodes/MutationObserver-disconnect.html
@@ -0,0 +1,48 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>MutationObservers: disconnect</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<h1>MutationObservers: disconnect</h1>
+<div id="log"></div>
+<section style="display: none">
+<p id='n00'></p>
+</section>
+<script>
+var n00 = document.getElementById('n00');
+var parentTest = async_test("subtree mutations");
+function masterMO(sequence, obs) {
+  parentTest.step(function() {
+    assert_equals(sequence.length, 4, "mutation records must match");
+  });
+  parentTest.done();
+}
+parentTest.step(function() {
+  (new MutationObserver(masterMO)).observe(n00.parentNode, {"subtree": true, "attributes": true});
+});
+
+var disconnectTest = async_test("disconnect discarded some mutations");
+function observerCallback(sequence, obs) {
+  disconnectTest.step(function() {
+    assert_equals(sequence.length, 1);
+    assert_equals(sequence[0].type, "attributes");
+    assert_equals(sequence[0].attributeName, "id");
+    assert_equals(sequence[0].oldValue, "latest");
+    disconnectTest.done();
+  });
+}
+
+var observer;
+disconnectTest.step(function() {
+  observer = new MutationObserver(observerCallback);
+  observer.observe(n00, {"attributes": true});
+  n00.id = "foo";
+  n00.id = "bar";
+  observer.disconnect();
+  observer.observe(n00, {"attributes": true, "attributeOldValue": true});
+  n00.id = "latest";
+  observer.disconnect();
+  observer.observe(n00, {"attributes": true, "attributeOldValue": true});
+  n00.id = "n0000";
+});
+</script>