1 files changed, 40 insertions, 0 deletions
diff --git a/testing/web-platform/tests/portals/predecessor-fires-unload.html b/testing/web-platform/tests/portals/predecessor-fires-unload.html
new file mode 100644
index 0000000000..cb6d98c01d
--- /dev/null
+++ b/testing/web-platform/tests/portals/predecessor-fires-unload.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/open-blank-host.js"></script>
+<script>
+function nextEvent(target, type) {
+  return new Promise((resolve, reject) => target.addEventListener(type, e => resolve(e), {once: true}));
+}
+
+function timePasses(delay) {
+  return new Promise((resolve, reject) => step_timeout(() => resolve(), delay));
+}
+
+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.html', location.href);
+    w.document.body.appendChild(portal);
+    await nextEvent(portal, 'load');
+    const pagehideFired = nextEvent(w, 'pagehide');
+    const unloadFired = nextEvent(w, 'unload');
+    await portal.activate();
+    assert_true((await pagehideFired) instanceof w.PageTransitionEvent);
+    assert_true((await unloadFired) instanceof w.Event);
+  } finally {
+    w.close();
+  }
+}, "pagehide and unload should fire if the predecessor is not adopted");
+
+promise_test(async () => {
+  assert_implements("HTMLPortalElement" in self);
+  localStorage.setItem('predecessor-fires-unload-events', '');
+  window.open('resources/predecessor-fires-unload-watch-unload.html', '_blank', 'noopener');
+  while (localStorage.getItem('predecessor-fires-unload-events') != 'pagehide unload') {
+    await timePasses(50);
+  }
+}, "pagehide and unload should fire if the predecessor is not adopted, even without a window/opener association");
+</script>