1 files changed, 32 insertions, 0 deletions
diff --git a/testing/web-platform/tests/dom/nodes/MutationObserver-cross-realm-callback-report-exception.html b/testing/web-platform/tests/dom/nodes/MutationObserver-cross-realm-callback-report-exception.html
new file mode 100644
index 0000000000..7d05c045b3
--- /dev/null
+++ b/testing/web-platform/tests/dom/nodes/MutationObserver-cross-realm-callback-report-exception.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>MutationObserver reports the exception from its callback in the callback's global object</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<iframe></iframe>
+<iframe></iframe>
+<iframe></iframe>
+<script>
+setup({ allow_uncaught_exception: true });
+
+const onerrorCalls = [];
+window.onerror = () => { onerrorCalls.push("top"); };
+frames[0].onerror = () => { onerrorCalls.push("frame0"); };
+frames[1].onerror = () => { onerrorCalls.push("frame1"); };
+frames[2].onerror = () => { onerrorCalls.push("frame2"); };
+
+async_test(t => {
+  window.onload = t.step_func(() => {
+    const target = frames[0].document.body;
+    const mo = new frames[0].MutationObserver(new frames[1].Function(`throw new parent.frames[2].Error("PASS");`));
+
+    mo.observe(target, { childList: true, subtree: true });
+    target.append("foo");
+
+    t.step_timeout(() => {
+      assert_array_equals(onerrorCalls, ["frame1"]);
+      t.done();
+    }, 4);
+  });
+});
+</script>