navigation-api/navigation-history-entry/index-not-in-entries.html

<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<iframe id="i" src="/common/blank.html"></iframe>
<script>
async_test(t => {
  // Wait for after the load event so that the navigation doesn't get converted
  // into a replace navigation.
  window.onload = () => t.step_timeout(t.step_func_done(() => {
    // Remove the entry by replacing it.
    let replaced_entry = navigation.currentEntry;
    assert_equals(replaced_entry.index, 0);
    navigation.navigate("#0", { history: "replace" });
    assert_equals(replaced_entry.index, -1);

    // Remove the entry by detaching its window.
    let iframe_entry = i.contentWindow.navigation.currentEntry;
    assert_equals(iframe_entry.index, 0);
    i.remove();
    assert_equals(iframe_entry.index, -1);
    t.done();
  }), 0);
}, "entry.index should return -1 when not in navigation.entries()");
</script>