Form constructor for testing form state persistence.
function form_test_state_persist($form, &$form_state) {
$form['title'] = array(
'#type' => 'textfield',
'#title' => 'title',
'#default_value' => 'DEFAULT',
'#required' => TRUE,
);
$form_state['value'] = 'State persisted.';
$form['submit'] = array(
'#type' => 'submit',
'#value' => t('Submit'),
);
return $form;
}