<?php
$node = (object)array(
  'type' => 'page',
);
$form_values = array(
  'title' => '',
  'body' => 'no title - should give an error, no?',
  'name' => '', //Anonymous
);
$output = drupal_execute('node_form', $form_values, $node);

// I expect the $output to contain some errors, but it contains 'node/123'.
// The doc of drupal_execute() says:
// Return value
// Any form validation errors encountered.
//
// While this looks like a redirection url. No problem if the redirection
// url is returned when there are no form validation errors, but here there
// should be a "Title field is required." error.