Helper function to enable entity translations.
function field_test_entity_info_translatable($entity_type = NULL, $translatable = NULL) {
drupal_static_reset('field_has_translation_handler');
$stored_value =& drupal_static(__FUNCTION__, array());
if (isset($entity_type)) {
$stored_value[$entity_type] = $translatable;
entity_info_cache_clear();
}
return $stored_value;
}