1 files changed, 38 insertions, 0 deletions
diff --git a/testing/web-platform/tests/portals/portals-set-src-after-activate.html b/testing/web-platform/tests/portals/portals-set-src-after-activate.html
new file mode 100644
index 0000000000..e485ef4d51
--- /dev/null
+++ b/testing/web-platform/tests/portals/portals-set-src-after-activate.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/open-blank-host.js"></script>
+<script>
+function nextMessage(target) {
+  return new Promise((resolve, reject) => {
+    target.addEventListener('message', e => resolve(e), {once: true});
+  });
+}
+
+promise_test(async () => {
+  assert_implements("HTMLPortalElement" in self);
+  const w = await openBlankPortalHost();
+  try {
+    const portal = w.document.createElement('portal');
+    portal.src = new URL('resources/simple-portal-adopts-predecessor.html', location.href);
+    w.document.body.appendChild(portal);
+    assert_equals((await nextMessage(portal)).data, 'ready');
+
+    // Intentionally don't await activation finishing; this should work
+    // even if activation is ongoing.
+    let activateDone = portal.activate();
+
+    // TODO(jbroman): It shouldn't be necessary to reinsert the element to
+    // navigate it again, either.
+    w.document.body.removeChild(portal);
+    portal.src = new URL('resources/simple-portal.html', location.href);
+    w.document.body.appendChild(portal);
+    assert_equals((await nextMessage(portal)).data, 'ready');
+
+    // But activation should still resolve, eventually.
+    await activateDone;
+  } finally {
+    w.close();
+  }
+}, "Tests that a portal element can be fully reused after activate has detached it");
+</script>