view_mode_test.module

<?php
/**
 * @file
 * Test module for Field UI display modes.
 */

/**
 * Implements hook_theme_registry_alter().
 */
function view_mode_test_theme_registry_alter(&$registry) {
  if ($hooks = state_get('entity_view_mode_theme_output_suggestions', array())) {
    foreach ($hooks as $hook) {
      if (isset($registry[$hook])) {
        $registry[$hook]['function'] = 'view_mode_test_return_suggestions';
      }
    }
  }
}

/**
 * Theme registry callback.
 */
function view_mode_test_return_suggestions(array $variables) {
  $suggestions = array();
  if (!empty($variables['theme_hook_suggestions'])) {
    $suggestions = $variables['theme_hook_suggestions'];
  }
  if (!empty($variables['theme_hook_suggestion'])) {
    $suggestions[] = $variables['theme_hook_suggestion'];
  }
  return array_reverse($suggestions);
}

/**
 * Implements hook_entity_view_mode_info().
 */
function view_mode_test_entity_view_mode_info() {
  $info['node']['info_1'] = array(
    'label' => t('Hook-defined display mode #1'),
  );
  $info['node']['info_2'] = array(
    'label' => t('Hook-defined display mode #2'),
    'custom settings' => FALSE,
  );
  $info['node']['info_3'] = array(
    'label' => t('Hook-defined display mode #3'),
  );
  $info['node']['full'] = array(
    'label' => t('Full display mode already defined by core.'),
    'custom settings' => TRUE,
  );

  $info['taxonomy_term']['info_1'] = array(
    'label' => t('Hook-defined display mode #1'),
    'custom settings' => TRUE,
  );

  // Invalid entity type.
  $info['invalid-type']['test'] = array(
    'label' => t('Test display mode'),
  );

  // Call entity_get_info() from inside this hook to test recursion prevention.
  foreach (entity_get_info() as $entity_type => $entity_info) {
    $info[$entity_type]['recursion'] = array(
      'label' => t('Recursion'),
    );
  }

  return $info;
}

/**
 * Implements hook_entity_view_mode_info_alter().
 */
function view_mode_test_entity_view_mode_info_alter(&$info) {
  $info['node']['info_2']['label'] = t('Hook-altered display mode');
  $info['node']['info_2']['custom settings'] = TRUE;
}