drupal/modules/simpletest/tests/file_test.module

<?php
// $Id$

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

/**
 * Implementation of hook_menu().
 */
function file_test_menu() {
  $items['file-test/upload'] = array(
    'title' => t('Upload test'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('_file_test_form'),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  return $items;
}

/**
 * Form to test file uploads.
 */
function _file_test_form(&$form_state) {
  $form['#attributes'] = array('enctype' => 'multipart/form-data');
  $form['file_test_upload'] = array(
    '#type' => 'file',
    '#title' => t('Upload an image'),
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );
  return $form;
}

/**
 * Process the upload.
 */
function _file_test_form_submit(&$form, &$form_state) {
  // Validate the uploaded picture.
  $file = file_save_upload('file_test_upload', array('file_validate_is_image' => array()));
  if ($file) {
    $form_state['values']['file_test_upload'] = $file;
    drupal_set_message(t('File @filepath was uploaded.', array('@filepath' => $file->filepath)));
  }
  else {
    drupal_set_message(t('Epic upload FAIL!'), 'error');
  }
}


/**
 * Reset/initialize the history of calls to the file_* hooks.
 */
function file_test_reset() {
  // Keep track of calls to these hooks
  $GLOBALS['file_test_results'] = array(
    'load' => array(),
    'validate' => array(),
    'download' => array(),
    'references' => array(),
    'status' => array(),
    'insert' => array(),
    'update' => array(),
    'copy' => array(),
    'move' => array(),
    'delete' => array(),
  );

  // These hooks will return these values.
  $GLOBALS['file_test_hook_return'] = array(
    'validate' => NULL,
    'download' => NULL,
    'references' => NULL,
  );
}

/**
 * Get the values passed to a the hook calls for a given operation.
 *
 * @param $op One of the hook_file_* operations.
 * @returns Array of the parameters passed to each call.
 */
function file_test_get_calls($op) {
  return $GLOBALS['file_test_results'][$op];
}

/**
 * Implementation of hook_file_load().
 */
function file_test_file_load(&$file) {
  $GLOBALS['file_test_results']['load'][] = func_get_args();
  // Assign a value on the object so that we can test that the $file is passed
  // by reference.
  $file->file_test['loaded'] = TRUE;
}

/**
 * Implementation of hook_file_validate().
 */
function file_test_file_validate(&$file) {
  $GLOBALS['file_test_results']['validate'][] = func_get_args();
  return $GLOBALS['file_test_hook_return']['validate'];
}

/**
 * Implementation of hook_file_status().
 */
function file_test_file_status(&$file) {
  $GLOBALS['file_test_results']['status'][] = func_get_args();
}

/**
 * Implementation of hook_file_download().
 */
function file_test_file_download(&$file) {
  $GLOBALS['file_test_results']['download'][] = func_get_args();
  return $GLOBALS['file_test_hook_return']['download'];
}

/**
 * Implementation of hook_file_references().
 */
function file_test_file_references(&$file) {
  $GLOBALS['file_test_results']['references'][] = func_get_args();
  return $GLOBALS['file_test_hook_return']['references'];
}

/**
 * Implementation of hook_file_insert().
 */
function file_test_file_insert(&$file) {
  $GLOBALS['file_test_results']['insert'][] = func_get_args();
}

/**
 * Implementation of hook_file_update().
 */
function file_test_file_update(&$file) {
  $GLOBALS['file_test_results']['update'][] = func_get_args();
}

/**
 * Implemenation of hook_file_copy().
 */
function file_test_file_copy(&$file, &$source) {
  $GLOBALS['file_test_results']['copy'][] = func_get_args();
}

/**
 * Implemenation of hook_file_move().
 */
function file_test_file_move(&$file, &$source) {
  $GLOBALS['file_test_results']['move'][] = func_get_args();
}

/**
 * Implementation of hook_file_delete().
 */
function file_test_file_delete(&$file) {
  $GLOBALS['file_test_results']['delete'][] = func_get_args();
}