1 files changed, 34 insertions, 0 deletions
diff --git a/testing/web-platform/tests/css/css-shadow-parts/invalidation-change-part-name-forward.html b/testing/web-platform/tests/css/css-shadow-parts/invalidation-change-part-name-forward.html
new file mode 100644
index 0000000000..f8da6d1f54
--- /dev/null
+++ b/testing/web-platform/tests/css/css-shadow-parts/invalidation-change-part-name-forward.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>CSS Shadow Parts - Invalidation change part name forward</title>
+    <meta href="mailto:fergal@chromium.org" rel="author" title="Fergal Daly">
+    <link href="http://www.google.com/" rel="author" title="Google">
+    <link href="https://drafts.csswg.org/css-shadow-parts/" rel="help">
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <script src="support/shadow-helper.js"></script>
+  </head>
+  <body>
+    <style>#c-e-outer::part(part-forwarded) { color: red; }</style>
+    <script>installCustomElement("custom-element-inner", "custom-element-inner-template");</script>
+    <template id="custom-element-inner-template">
+      <style>span { color: green; }</style>
+      <span id="part" part="partp">This text</span>
+    </template>
+    <script>installCustomElement("custom-element-outer", "custom-element-outer-template");</script>
+    <template id="custom-element-outer-template"><custom-element-inner id="c-e-inner" exportparts="partp: part-forwarded"></custom-element-inner></template>
+    The following text should be green:
+    <custom-element-outer id="c-e-outer"></custom-element-outer>
+    <script>
+      "use strict";
+      test(function() {
+        const part = getElementByShadowIds(document, ["c-e-outer", "c-e-inner", "part"]);
+        const before = window.getComputedStyle(part).color;
+        part.setAttribute("part", "new-partp");
+        const after = window.getComputedStyle(part).color;
+        assert_not_equals(before, after);
+      }, "Part in selected host changed color");
+    </script>
+  </body>
+</html>