1 files changed, 33 insertions, 0 deletions
diff --git a/testing/web-platform/tests/navigation-api/navigation-methods/forward-to-pruned-entry.html b/testing/web-platform/tests/navigation-api/navigation-methods/forward-to-pruned-entry.html
new file mode 100644
index 0000000000..05f70c5c2d
--- /dev/null
+++ b/testing/web-platform/tests/navigation-api/navigation-methods/forward-to-pruned-entry.html
@@ -0,0 +1,33 @@
+<!doctype html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+promise_test(async t => {
+  // Wait for after the load event so that the navigation doesn't get converted
+  // into a replace navigation.
+  await new Promise(resolve => window.onload = () => t.step_timeout(resolve, 0));
+  await navigation.navigate("#foo").finished;
+  assert_equals(navigation.entries().length, 2);
+  await navigation.back().finished;
+  assert_equals(navigation.currentEntry.index, 0);
+
+  // Traverse forward then immediately do a same-document push. This will
+  // truncate the back forward list, and by the time the traverse commits, the
+  // destination key will no longer be present in navigation.entries(). The
+  // traverse should abort. Because the traverse aborts before the navigate
+  // event fires, the navigateerror event should not fire.
+  navigation.onnavigateerror = t.unreached_func("navigateerror should not fire");
+  let forward_value = navigation.forward();
+  await navigation.navigate("#clobber").finished;
+  assert_equals(navigation.currentEntry.index, 1);
+  await promise_rejects_dom(t, "AbortError", forward_value.committed);
+  await promise_rejects_dom(t, "AbortError", forward_value.finished);
+
+  // This leaves navigation.entries() in a consistent state where traversing
+  // back and forward still works.
+  await navigation.back().finished;
+  assert_equals(navigation.currentEntry.index, 0);
+  await navigation.forward().finished;
+  assert_equals(navigation.currentEntry.index, 1);
+}, "If forward pruning clobbers the target of a traverse, abort");
+</script>