1 files changed, 61 insertions, 0 deletions
diff --git a/testing/web-platform/tests/dom/observable/tentative/observable-takeUntil.window.js b/testing/web-platform/tests/dom/observable/tentative/observable-takeUntil.window.js
new file mode 100644
index 0000000000..e4906d5f16
--- /dev/null
+++ b/testing/web-platform/tests/dom/observable/tentative/observable-takeUntil.window.js
@@ -0,0 +1,61 @@
+async function loadIframeAndReturnContentWindow() {
+   // Create and attach an iframe.
+  const iframe = document.createElement('iframe');
+  const iframeLoadPromise = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+  document.body.append(iframe);
+  await iframeLoadPromise;
+  return iframe.contentWindow;
+}
+
+// This is a regression test to ensure there is no crash inside `takeUntil()`
+// once `notifier` detaches its document, before `source` is subscribed to.
+promise_test(async () => {
+  // Hang this off of the main document's global, so the child can easily reach
+  // it.
+  window.results = [];
+  const contentWin = await loadIframeAndReturnContentWindow();
+
+  contentWin.eval(`
+    const parentResults = parent.results;
+
+    const source = new Observable(() => parentResults.push('source subscribed'));
+    const notifier = new Observable(() => {
+      parentResults.push('notifier subscribed');
+
+      // Detach this child document.
+      window.frameElement.remove();
+      parentResults.push('notifier has detached document');
+    });
+
+    source.takeUntil(notifier).subscribe();
+  `);
+
+  assert_array_equals(results, ["notifier subscribed", "notifier has detached document"]);
+}, "takeUntil(): notifier Observable detaches document before source " +
+   "Observable would be subscribed to");
+
+promise_test(async () => {
+  window.results = [];
+  const contentWin = await loadIframeAndReturnContentWindow();
+
+  contentWin.eval(`
+    let completeSubscriber, errorSubscriber, notifierSubscriber;
+    const sourceComplete = new Observable(subscriber => completeSubscriber = subscriber);
+    const sourceError = new Observable(subscriber => errorSubscriber = subscriber);
+    const notifier = new Observable(subscriber => notifierSubscriber = subscriber);
+
+    sourceComplete.takeUntil(notifier).subscribe();
+    sourceError.takeUntil(notifier).subscribe();
+
+    // Detach this child document.
+    window.frameElement.remove();
+
+    completeSubscriber.complete();
+    errorSubscriber.error('error');
+    notifierSubscriber.error('error');
+  `);
+}, "takeUntil(): Source and notifier internal observers do not crash in a " +
+    "detached document");