1 files changed, 28 insertions, 0 deletions
diff --git a/testing/web-platform/tests/element-timing/fixed-id-identifier.html b/testing/web-platform/tests/element-timing/fixed-id-identifier.html
new file mode 100644
index 0000000000..749b9ada2f
--- /dev/null
+++ b/testing/web-platform/tests/element-timing/fixed-id-identifier.html
@@ -0,0 +1,28 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Element Timing: entry does not change its id or identifier value</title>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/element-timing-helpers.js"></script>
+<p elementtiming='my_identifier' id='my_id'>Text</p>
+<script>
+  async_test(function (t) {
+    assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented");
+    const observer = new PerformanceObserver(
+      t.step_func_done(function(entryList) {
+        assert_equals(entryList.getEntries().length, 1);
+        const entry = entryList.getEntries()[0];
+        assert_equals(entry.id, 'my_id');
+        assert_equals(entry.identifier, 'my_identifier');
+        const element = document.getElementById('my_id');
+        element.id = 'other_id';
+        element.setAttribute('elementtiming', 'other_identifier');
+        assert_equals(entry.id, 'my_id');
+        assert_equals(entry.identifier, 'my_identifier');
+      })
+    );
+    observer.observe({type: 'element', buffered: true});
+  }, 'PerformanceElementTiming id and identifier do not change when Element changes.');
+</script>
+</body>