path: root/modules/simpletest/tests/form_test.module

<?php
// $Id$

/**
 * @file
 * Helper module for the form API tests.
 */

/**
 * Implements hook_menu().
 */
function form_test_menu() {
  $items['form-test/validate'] = array(
    'title' => 'Form validation handlers test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_test_validate_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  $items['form-test/limit-validation-errors'] = array(
    'title' => 'Form validation with some error suppression',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_test_limit_validation_errors_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form_test/tableselect/multiple-true'] = array(
    'title' => 'Tableselect checkboxes test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_form_test_tableselect_multiple_true_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  $items['form_test/tableselect/multiple-false'] = array(
    'title' => 'Tableselect radio button test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_form_test_tableselect_multiple_false_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  $items['form_test/tableselect/empty-text'] = array(
    'title' => 'Tableselect empty text test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_form_test_tableselect_empty_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  $items['form_test/tableselect/advanced-select'] = array(
    'title' => 'Tableselect js_select tests',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_form_test_tableselect_js_select_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form_test/form-storage'] = array(
    'title' => 'Form storage test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_test_storage_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form_test/wrapper-callback'] = array(
    'title' => 'Form wrapper callback test',
    'page callback' => 'form_test_wrapper_callback',
    'page arguments' => array('form_test_wrapper_callback_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form_test/form-state-values-clean'] = array(
    'title' => 'Form state values clearance test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_test_form_state_values_clean_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form-test/checkbox'] = array(
    'title' => t('Form test'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_form_test_checkbox'),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );

  $items['form-test/disabled-elements'] = array(
    'title' => t('Form test'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_form_test_disabled_elements'),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );

  $items['form-test/form-rebuild-preserve-values'] = array(
    'title' => 'Form values preservation during rebuild test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_test_form_rebuild_preserve_values_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form_test/form-labels'] = array(
    'title' => 'Form label test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_label_test_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  $items['form-test/state-persist'] = array(
    'title' => 'Form state persistence without storage',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_test_state_persist'),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Form builder for testing drupal_validate_form().
 *
 * Serves for testing form processing and alterations by form validation
 * handlers, especially for the case of a validation error:
 * - form_set_value() should be able to alter submitted values in
 *   $form_state['values'] without affecting the form element.
 * - #element_validate handlers should be able to alter the $element in the form
 *   structure and the alterations should be contained in the rebuilt form.
 * - #validate handlers should be able to alter the $form and the alterations
 *   should be contained in the rebuilt form.
 */
function form_test_validate_form($form, &$form_state) {
  $form['name'] = array(
    '#type' => 'textfield',
    '#title' => 'Name',
    '#default_value' => '',
    '#element_validate' => array('form_test_element_validate_name'),
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Save',
  );

  // To simplify this test, enable form caching and use form storage to
  // remember our alteration.
  $form_state['cache'] = TRUE;

  return $form;
}

/**
 * Form element validation handler for 'name' in form_test_validate_form().
 */
function form_test_element_validate_name(&$element, &$form_state) {
  $triggered = FALSE;
  if ($form_state['values']['name'] == 'element_validate') {
    // Alter the form element.
    $element['#value'] = '#value changed by #element_validate';
    // Alter the submitted value in $form_state.
    form_set_value($element, 'value changed by form_set_value() in #element_validate', $form_state);

    $triggered = TRUE;
  }
  if ($form_state['values']['name'] == 'element_validate_access') {
    $form_state['storage']['form_test_name'] = $form_state['values']['name'];
    // Alter the form element.
    $element['#access'] = FALSE;

    $triggered = TRUE;
  }
  elseif (!empty($form_state['storage']['form_test_name'])) {
    // To simplify this test, just take over the element's value into $form_state.
    form_set_value($element, $form_state['storage']['form_test_name'], $form_state);

    $triggered = TRUE;
  }

  if ($triggered) {
    // Output the element's value from $form_state.
    drupal_set_message(t('@label value: @value', array('@label' => $element['#title'], '@value' => $form_state['values']['name'])));

    // Trigger a form validation error to see our changes.
    form_set_error('');
  }
}

/**
 * Form validation handler for form_test_validate_form().
 */
function form_test_validate_form_validate(&$form, &$form_state) {
  if ($form_state['values']['name'] == 'validate') {
    // Alter the form element.
    $form['name']['#value'] = '#value changed by #validate';
    // Alter the submitted value in $form_state.
    form_set_value($form['name'], 'value changed by form_set_value() in #validate', $form_state);
    // Output the element's value from $form_state.
    drupal_set_message(t('@label value: @value', array('@label' => $form['name']['#title'], '@value' => $form_state['values']['name'])));

    // Trigger a form validation error to see our changes.
    form_set_error('');
  }
}

/**
 * Builds a simple form with a button triggering partial validation.
 */
function form_test_limit_validation_errors_form($form, &$form_state) {
  $form['title'] = array(
    '#type' => 'textfield',
    '#title' => 'Title',
    '#required' => TRUE,
  );
  $form['test'] = array(
    '#type' => 'textfield',
    '#element_validate' => array('form_test_limit_validation_errors_element_validate_test'),
  );
  $form['actions']['partial'] = array(
    '#type' => 'submit',
    '#limit_validation_errors' => array(array('test')),
    '#submit' => array(),
    '#value' => t('Partial validate'),
  );
  $form['actions']['full'] = array(
    '#type' => 'submit',
    '#value' => t('Full validate'),
  );
  return $form;
}

/**
 * Form element validation handler for the 'test' element.
 */
function form_test_limit_validation_errors_element_validate_test(&$element, &$form_state) {
  if ($element['#value'] == 'invalid') {
    form_error($element, 'Test element is invalid');
  }
}

/**
 * Create a header and options array. Helper function for callbacks.
 */
function _form_test_tableselect_get_data() {
  $header = array(
    'one' => t('One'),
    'two' => t('Two'),
    'three' => t('Three'),
    'four' => t('Four'),
  );

  $options['row1'] = array(
    'one' => 'row1col1',
    'two' => t('row1col2'),
    'three' => t('row1col3'),
    'four' => t('row1col4'),
  );

  $options['row2'] = array(
    'one' => 'row2col1',
    'two' => t('row2col2'),
    'three' => t('row2col3'),
    'four' => t('row2col4'),
  );

  $options['row3'] = array(
    'one' => 'row3col1',
    'two' => t('row3col2'),
    'three' => t('row3col3'),
    'four' => t('row3col4'),
  );

  return array($header, $options);
}

/**
 * Build a form to test the tableselect element.
 *
 * @param $form_state
 *   The form_state
 * @param $element_properties
 *   An array of element properties for the tableselect element.
 *
 * @return
 *   A form with a tableselect element and a submit button.
 */
function _form_test_tableselect_form_builder($form, $form_state, $element_properties) {
  list($header, $options) = _form_test_tableselect_get_data();

  $form['tableselect'] = $element_properties;

  $form['tableselect'] += array(
    '#type' => 'tableselect',
    '#header' => $header,
    '#options' => $options,
    '#multiple' => FALSE,
    '#empty' => t('Empty text.'),
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );

  return $form;
}

/**
 * Test the tableselect #multiple = TRUE functionality.
 */
function _form_test_tableselect_multiple_true_form($form, $form_state) {
  return _form_test_tableselect_form_builder($form, $form_state, array('#multiple' => TRUE));
}

/**
 * Process the tableselect #multiple = TRUE submitted values.
 */
function _form_test_tableselect_multiple_true_form_submit($form, &$form_state) {
  $selected = $form_state['values']['tableselect'];
  foreach ($selected as $key => $value) {
    drupal_set_message(t('Submitted: @key = @value', array('@key' => $key, '@value' => $value)));
  }
}

/**
 * Test the tableselect #multiple = FALSE functionality.
 */
function _form_test_tableselect_multiple_false_form($form, $form_state) {
  return _form_test_tableselect_form_builder($form, $form_state, array('#multiple' => FALSE));
}

/**
 * Process the tableselect #multiple = FALSE submitted values.
 */
function _form_test_tableselect_multiple_false_form_submit($form, &$form_state) {
  drupal_set_message(t('Submitted: @value', array('@value' => $form_state['values']['tableselect'])));
}

/**
 * Test functionality of the tableselect #empty property.
 */
function _form_test_tableselect_empty_form($form, $form_state) {
  return _form_test_tableselect_form_builder($form, $form_state, array('#options' => array()));
}

/**
 * Test functionality of the tableselect #js_select property.
 */
function _form_test_tableselect_js_select_form($form, $form_state, $action) {
  switch ($action) {
    case 'multiple-true-default':
      $options = array('#multiple' => TRUE);
      break;

    case 'multiple-false-default':
      $options = array('#multiple' => FALSE);
      break;

    case 'multiple-true-no-advanced-select':
      $options = array('#multiple' => TRUE, '#js_select' => FALSE);
      break;

    case 'multiple-false-advanced-select':
      $options = array('#multiple' => FALSE, '#js_select' => TRUE);
      break;
  }

  return _form_test_tableselect_form_builder($form, $form_state, $options);
}

/**
 * A multistep form for testing the form storage.
 *
 * It uses two steps for editing a virtual "thing". Any changes to it are saved
 * in the form storage and have to be present during any step. By setting the
 * request parameter "cache" the form can be tested with caching enabled, as
 * it would be the case, if the form would contain some #ajax callbacks.
 *
 * @see form_test_storage_form_submit().
 */
function form_test_storage_form($form, &$form_state) {
  if ($form_state['rebuild']) {
    $form_state['input'] = array();
  }
  // Initialize
  if (empty($form_state['storage'])) {
    if (empty($form_state['input'])) {
      $_SESSION['constructions'] = 0;
    }
    // Put the initial thing into the storage
    $form_state['storage'] = array(
      'thing' => array(
        'title' => 'none',
        'value' => '',
      ),
    );
  }
  // Count how often the form is constructed.
  $_SESSION['constructions']++;
  drupal_set_message("Form constructions: ". $_SESSION['constructions']);

  $form['title'] = array(
    '#type' => 'textfield',
    '#title' => 'Title',
    '#default_value' => $form_state['storage']['thing']['title'],
    '#required' => TRUE,
  );
  $form['value'] = array(
    '#type' => 'textfield',
    '#title' => 'Value',
    '#default_value' => $form_state['storage']['thing']['value'],
    '#element_validate' => array('form_test_storage_element_validate_value_cached'),
  );
  $form['button'] = array(
    '#type' => 'button',
    '#value' => 'Reload',
    // Reload the form (don't rebuild), thus we start at the initial step again.
  );
  $form['continue_button'] = array(
    '#type' => 'button',
    '#value' => 'Reset',
    // Rebuilds the form without keeping the values.
    '#validate' => array('form_storage_test_form_continue_validate'),
  );
  $form['continue_submit'] = array(
    '#type' => 'submit',
    '#value' => 'Continue submit',
    '#submit' => array('form_storage_test_form_continue_submit'),
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Save',
  );

  if (isset($_REQUEST['cache'])) {
    // Manually activate caching, so we can test that the storage keeps working
    // when it's enabled.
    $form_state['cache'] = TRUE;
  }

  return $form;
}

/**
 * Form element validation handler for 'value' element in form_test_storage_form().
 *
 * Tests updating of cached form storage during validation.
 */
function form_test_storage_element_validate_value_cached($element, &$form_state) {
  // If caching is enabled and we receive a certain value, change the storage.
  // This presumes that another submitted form value triggers a validation error
  // elsewhere in the form. Form API should still update the cached form storage
  // though.
  if (isset($_REQUEST['cache']) && $form_state['values']['value'] == 'change_title') {
    $form_state['storage']['thing']['changed'] = TRUE;
  }
}

/**
 * Form submit handler to continue multi-step form.
 */
function form_storage_test_form_continue_submit($form, &$form_state) {
  $form_state['storage']['thing']['title'] = $form_state['values']['title'];
  $form_state['storage']['thing']['value'] = $form_state['values']['value'];
  $form_state['rebuild'] = TRUE;
}

/**
 * Form validation handler, which doesn't preserve the values but rebuilds the
 * form. We cannot use a submit handler here, as buttons of type button don't
 * submit the form.
 */
function form_storage_test_form_continue_validate($form, &$form_state) {
  $form_state['rebuild'] = TRUE;
}

/**
 * Form submit handler to finish multi-step form.
 */
function form_test_storage_form_submit($form, &$form_state) {
  drupal_set_message("Title: ". check_plain($form_state['values']['title']));
  drupal_set_message("Form constructions: ". $_SESSION['constructions']);
  if (isset($form_state['storage']['thing']['changed'])) {
    drupal_set_message("The thing has been changed.");
  }
  $form_state['redirect'] = 'node';
}

 /**
 * A form for testing form labels and required marks.
 */
function form_label_test_form(&$form_state) {
  $form['form_checkboxes_test'] = array(
    '#type' => 'checkboxes',
    '#title' => t('Checkboxes test'),
    '#options' => array(
      'first-checkbox' => t('First checkbox'),
      'second-checkbox' => t('Second checkbox'),
      'third-checkbox' => t('Third checkbox'),
    ),
  );
  $form['form_radios_test'] = array(
    '#type' => 'radios',
    '#title' => t('Radios test'),
    '#options' => array(
      'first-radio' => t('First radio'),
      'second-radio' => t('Second radio'),
      'third-radio' => t('Third radio'),
    ),
  );
  $form['form_checkbox_test'] = array(
    '#type' => 'checkbox',
    '#title' => t('Checkbox test'),
  );
  $form['form_textfield_test_title_and_required'] = array(
    '#type' => 'textfield',
    '#title' => t('Textfield test for required with title'),
    '#required' => TRUE,
  );
  $form['form_textfield_test_no_title_required'] = array(
    '#type' => 'textfield',
    // We use an empty title, since not setting #title supresses the label
    // and required marker.
    '#title' => '',
    '#required' => TRUE,
  );
  $form['form_textfield_test_title'] = array(
    '#type' => 'textfield',
    '#title' => t('Textfield test for title only'),
    // Not required.
  );
  $form['form_textfield_test_title_after'] = array(
    '#type' => 'textfield',
    '#title' => t('Textfield test for title after element'),
    '#title_display' => 'after',
  );
  // Textfield test for title set not to display
  $form['form_textfield_test_title_no_show'] = array(
    '#type' => 'textfield',
  );

  return $form;
}

/**
 * Menu callback; Invokes a form builder function with a wrapper callback.
 */
function form_test_wrapper_callback($form_id) {
  $form_state = array(
    'build_info' => array('args' => array()),
    'wrapper_callback' => 'form_test_wrapper_callback_wrapper',
  );
  return drupal_build_form($form_id, $form_state);
}

/**
 * Form wrapper for form_test_wrapper_callback_form().
 */
function form_test_wrapper_callback_wrapper($form, &$form_state) {
  $form['wrapper'] = array('#markup' => 'Form wrapper callback element output.');
  return $form;
}

/**
 * Form builder for form wrapper callback test.
 */
function form_test_wrapper_callback_form($form, &$form_state) {
  $form['builder'] = array('#markup' => 'Form builder element output.');
  return $form;
}

/**
 * Form builder for form_state_values_clean() test.
 */
function form_test_form_state_values_clean_form($form, &$form_state) {
  // Build an example form containing multiple submit and button elements; not
  // only on the top-level.
  $form = array('#tree' => TRUE);
  $form['foo'] = array('#type' => 'submit', '#value' => t('Submit'));
  $form['bar'] = array('#type' => 'submit', '#value' => t('Submit'));
  $form['beer'] = array('#type' => 'value', '#value' => 1000);
  $form['baz']['foo'] = array('#type' => 'button', '#value' => t('Submit'));
  $form['baz']['baz'] = array('#type' => 'submit', '#value' => t('Submit'));
  $form['baz']['beer'] = array('#type' => 'value', '#value' => 2000);
  return $form;
}

/**
 * Form submit handler for form_state_values_clean() test form.
 */
function form_test_form_state_values_clean_form_submit($form, &$form_state) {
  form_state_values_clean($form_state);
  drupal_json_output($form_state['values']);
  exit;
}

/**
 * Build a form to test a checkbox.
 */
function _form_test_checkbox($form, &$form_state) {
  // A required checkbox.
  $form['required_checkbox'] = array(
    '#type' => 'checkbox',
    '#required' => TRUE,
    '#title' => 'required_checkbox',
  );

  // A disabled checkbox should get its default value back.
  $form['disabled_checkbox_on'] = array(
    '#type' => 'checkbox',
    '#disabled' => TRUE,
    '#return_value' => 'disabled_checkbox_on',
    '#default_value' => 'disabled_checkbox_on',
    '#title' => 'disabled_checkbox_on',
  );
  $form['disabled_checkbox_off'] = array(
    '#type' => 'checkbox',
    '#disabled' => TRUE,
    '#return_value' => 'disabled_checkbox_off',
    '#default_value' => NULL,
    '#title' => 'disabled_checkbox_off',
  );

  // A checkbox is active when #default_value == #return_value.
  $form['checkbox_on'] = array(
    '#type' => 'checkbox',
    '#return_value' => 'checkbox_on',
    '#default_value' => 'checkbox_on',
    '#title' => 'checkbox_on',
  );

  // But inactive in any other case.
  $form['checkbox_off'] = array(
    '#type' => 'checkbox',
    '#return_value' => 'checkbox_off',
    '#default_value' => 'checkbox_on',
    '#title' => 'checkbox_off',
  );

  // Checkboxes with a #return_value of '0' are supported.
  $form['zero_checkbox_on'] = array(
    '#type' => 'checkbox',
    '#return_value' => '0',
    '#default_value' => '0',
    '#title' => 'zero_checkbox_on',
  );

  // In that case, passing a #default_value != '0' means that the checkbox is off.
  $form['zero_checkbox_off'] = array(
    '#type' => 'checkbox',
    '#return_value' => '0',
    '#default_value' => '1',
    '#title' => 'zero_checkbox_off',
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit')
  );

  return $form;
}

/**
 * Return the form values via JSON.
 */
function _form_test_checkbox_submit($form, &$form_state) {
  drupal_json_output($form_state['values']);
  exit();
}

/**
 * Build a form to test disabled elements.
 */
function _form_test_disabled_elements($form, &$form_state) {
  // Elements that take a simple default value.
  foreach (array('textfield', 'textarea', 'hidden') as $type) {
    $form[$type] = array(
      '#type' => $type,
      '#title' => $type,
      '#default_value' => $type,
      '#disabled' => TRUE,
    );
  }

  // Multiple values option elements.
  foreach (array('checkboxes', 'select') as $type) {
    $form[$type . '_multiple'] = array(
      '#type' => $type,
      '#title' => $type . ' (multiple)',
      '#options' => array(
        'test_1' => 'Test 1',
        'test_2' => 'Test 2',
      ),
      '#multiple' => TRUE,
      '#default_value' => array('test_2' => 'test_2'),
      '#disabled' => TRUE,
    );
  }

  // Single values option elements.
  foreach (array('radios', 'select') as $type) {
    $form[$type . '_single'] = array(
      '#type' => $type,
      '#title' => $type . ' (single)',
      '#options' => array(
        'test_1' => 'Test 1',
        'test_2' => 'Test 2',
      ),
      '#multiple' => FALSE,
      '#default_value' => 'test_2',
      '#disabled' => TRUE,
    );
  }

  // Checkbox and radio.
  foreach (array('checkbox', 'radio') as $type) {
    $form[$type . '_unchecked'] = array(
      '#type' => $type,
      '#title' => $type . ' (unchecked)',
      '#return_value' => 1,
      '#default_value' => 0,
      '#disabled' => TRUE,
    );
    $form[$type . '_checked'] = array(
      '#type' => $type,
      '#title' => $type . ' (checked)',
      '#return_value' => 1,
      '#default_value' => 1,
      '#disabled' => TRUE,
    );
  }

  // Weight.
  $form['weight'] = array(
    '#type' => 'weight',
    '#title' => 'weight',
    '#default_value' => 10,
    '#disabled' => TRUE,
  );

  // Date.
  $form['date'] = array(
    '#type' => 'date',
    '#title' => 'date',
    '#disabled' => TRUE,
    '#default_value' => array(
      'day' => 19,
      'month' => 11,
      'year' => 1978,
    ),
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );

  return $form;
}

/**
 * Return the form values via JSON.
 */
function _form_test_disabled_elements_submit($form, &$form_state) {
  drupal_json_output($form_state['values']);
  exit();
}

/**
 * Form builder for testing preservation of values during a rebuild.
 */
function form_test_form_rebuild_preserve_values_form($form, &$form_state) {
  // Start the form with two checkboxes, to test different defaults, and a
  // textfield, to test more than one element type.
  $form = array(
    'checkbox_1_default_off' => array(
      '#type' => 'checkbox',
      '#title' => t('This checkbox defaults to unchecked.'),
      '#default_value' => FALSE,
    ),
    'checkbox_1_default_on' => array(
      '#type' => 'checkbox',
      '#title' => t('This checkbox defaults to checked.'),
      '#default_value' => TRUE,
    ),
    'text_1' => array(
      '#type' => 'textfield',
      '#title' => t('This textfield has a non-empty default value.'),
      '#default_value' => 'DEFAULT 1',
    ),
  );
  // Provide an 'add more' button that rebuilds the form with an additional two
  // checkboxes and a textfield. The test is to make sure that the rebuild
  // triggered by this button preserves the user input values for the initial
  // elements and initializes the new elements with the correct default values.
  if (empty($form_state['storage']['add_more'])) {
    $form['add_more'] = array(
      '#type' => 'submit',
      '#value' => 'Add more',
      '#submit' => array('form_test_form_rebuild_preserve_values_form_add_more'),
    );
  }
  else {
    $form += array(
      'checkbox_2_default_off' => array(
        '#type' => 'checkbox',
        '#title' => t('This checkbox defaults to unchecked.'),
        '#default_value' => FALSE,
      ),
      'checkbox_2_default_on' => array(
        '#type' => 'checkbox',
        '#title' => t('This checkbox defaults to checked.'),
        '#default_value' => TRUE,
      ),
      'text_2' => array(
        '#type' => 'textfield',
        '#title' => t('This textfield has a non-empty default value.'),
        '#default_value' => 'DEFAULT 2',
      ),
    );
  }
  // A submit button that finishes the form workflow (does not rebuild).
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Submit',
  );
  return $form;
}

/**
 * Button submit handler for form_test_form_rebuild_preserve_values_form().
 */
function form_test_form_rebuild_preserve_values_form_add_more($form, &$form_state) {
  // Rebuild, to test preservation of input values.
  $form_state['storage']['add_more'] = TRUE;
  $form_state['rebuild'] = TRUE;
}

/**
 * Form submit handler for form_test_form_rebuild_preserve_values_form().
 */
function form_test_form_rebuild_preserve_values_form_submit($form, &$form_state) {
  // Finish the workflow. Do not rebuild.
  drupal_set_message(t('Form values: %values', array('%values' => var_export($form_state['values'], TRUE))));
}

/**
 * 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;
}

/**
 * Submit handler.
 *
 * @see form_test_state_persist()
 */
function form_test_state_persist_submit($form, &$form_state) {
  drupal_set_message($form_state['value']);
  $form_state['rebuild'] = TRUE;
}

/**
 * Implements hook_form_FORM_ID_alter().
 *
 * @see form_test_state_persist()
 */
function form_test_form_form_test_state_persist_alter(&$form, &$form_state) {
  // Simulate a form alter implementation inserting form elements that enable
  // caching of the form, e.g. elements having #ajax.
  if (!empty($_REQUEST['cache'])) {
    $form_state['cache'] = TRUE;
  }
}

/**
 * Form builder to test programmatic form submissions.
 */
function form_test_programmatic_form($form, &$form_state) {
  $form['submitted_field'] = array(
    '#title' => 'Submitted',
    '#type' => 'textfield',
  );

  return $form;
}

/**
 * Form validation handler for programmatic form submissions.
 *
 * To test that the validation handler is correctly executed, the field value is
 * explicitly required here.
 */
function form_test_programmatic_form_validate($form, &$form_state) {
  if (empty($form_state['values']['submitted_field'])) {
    form_set_error('submitted_field', t('Submitted field is required.'));
  }
}

/**
 * Form submit handler for programmatic form submissions.
 *
 * To test that the submission handler is correctly executed, we store the
 * submitted value in a place we can access from the caller context.
 */
function form_test_programmatic_form_submit($form, &$form_state) {
  $form_state['storage']['programmatic_form_submit'] = $form_state['values']['submitted_field'];
}


/**
 * Implements hook_form_FORM_ID_alter() for the registration form.
 */
function form_test_form_user_register_form_alter(&$form, &$form_state) {
  $form['test_rebuild'] = array(
    '#type' => 'submit',
    '#value' => t('Rebuild'),
    '#submit' => array('form_test_user_register_form_rebuild'),
  );
  // If requested, add the test field by attaching the node page form.
  if (!empty($_REQUEST['field'])) {
    $node = (object)array('type' => 'page');
    field_attach_form('node', $node, $form, $form_state);
    // The form API requires the builder function to set rebuilding, so do so.
    $form['#builder_function'] = 'form_test_user_register_form_rebuild';
  }
}

/**
 * Submit callback that just lets the form rebuild.
 */
function form_test_user_register_form_rebuild($form, &$form_state) {
  drupal_set_message('Form rebuilt.');
  $form_state['rebuild'] = TRUE;
}