drupal/modules/simpletest/tests/file_test.module

<?php
// $Id$

/**
 * @file
 * Helper module for the file tests.
 *
 * The caller is must call file_test_reset() to initializing this module before
 * calling file_test_get_calls() or file_test_set_return().
 */

/**
 * 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['file_test_replace'] = array(
    '#type' => 'select',
    '#title' => t('Replace existing image'),
    '#options' => array(
      FILE_EXISTS_RENAME => t('Appends number until name is unique'),
      FILE_EXISTS_REPLACE => t('Replace the existing file'),
      FILE_EXISTS_ERROR => t('Fail with an error'),
    ),
    '#default_value' => FILE_EXISTS_RENAME,
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );
  return $form;
}

/**
 * Process the upload.
 */
function _file_test_form_submit(&$form, &$form_state) {
  // Process the upload and validate that it is an image. Note: we're using the
  // form value for the $replace parameter.
  $file = file_save_upload('file_test_upload', array('file_validate_is_image' => array()), FALSE, $form_state['values']['file_test_replace']);
  if ($file) {
    $form_state['values']['file_test_upload'] = $file;
    drupal_set_message(t('File @filepath was uploaded.', array('@filepath' => $file->filepath)));
    drupal_set_message(t('You WIN!'));
  }
  elseif ($file === FALSE) {
    drupal_set_message(t('Epic upload FAIL!'), 'error');
  }
}


/**
 * Reset/initialize the history of calls to the file_* hooks.
 *
 * @see the getter/setter functions file_test_get_calls() and file_test_reset().
 */
function file_test_reset() {
  // Keep track of calls to these hooks
  $results = array(
    'load' => array(),
    'validate' => array(),
    'download' => array(),
    'references' => array(),
    'insert' => array(),
    'update' => array(),
    'copy' => array(),
    'move' => array(),
    'delete' => array(),
  );
  variable_set('file_test_results', $results);

  // These hooks will return these values, @see file_test_set_return().
  $return = array(
    'validate' => array(),
    'download' => NULL,
    'references' => NULL,
  );
  variable_set('file_test_return', $return);
}

/**
 * Get the arguments passed to invocation of a given hook since
 * file_test_reset() was last called.
 *
 * @param $op
 *   One of the hook_file_* operations: 'load', 'validate', 'download',
 *   'references', 'insert', 'update', 'copy', 'move', 'delete'.
 * @returns
 *   Array of the parameters passed to each call.
 * @see _file_test_log_call() and file_test_reset()
 */
function file_test_get_calls($op) {
  $results = variable_get('file_test_results', array());
  return $results[$op];
}

/**
 * Get an array with the calls for all hooks.
 *
 * @return
 *   An array keyed by hook name ('load', 'validate', 'download',
 *   'references', 'insert', 'update', 'copy', 'move', 'delete') with values
 *   being arrays of parameters passed to each call.
 */
function file_test_get_all_calls() {
  return variable_get('file_test_results', array());
}

/**
 * Store the values passed to a hook invocation.
 *
 * @param $op
 *   One of the hook_file_* operations: 'load', 'validate', 'download',
 *   'references', 'insert', 'update', 'copy', 'move', 'delete'.
 * @param $args
 *   Values passed to hook.
 * @see file_test_get_calls() and file_test_reset()
 */
function _file_test_log_call($op, $args) {
  $results = variable_get('file_test_results', array());
  $results[$op][] = $args;
  variable_set('file_test_results', $results);
}

/**
 * Load the appropriate return value.
 *
 * @param $op
 *   One of the hook_file_[validate,download,references] operations.
 * @return
 *   Value set by file_test_set_return().
* @see file_test_set_return() and file_test_reset().
 */
function _file_test_get_return($op) {
  $return = variable_get('file_test_return', array($op => NULL));
  return $return[$op];
}

/**
 * Assign a return value for a given operation.
 *
 * @param $op
 *   One of the hook_file_[validate,download,references] operations.
 * @param $value
 *   Value for the hook to return.
 * @see _file_test_get_return() and file_test_reset().
 */
function file_test_set_return($op, $value) {
  $return = variable_get('file_test_return', array());
  $return[$op] = $value;
  variable_set('file_test_return', $return);
}

/**
 * Implementation of hook_file_load().
 */
function file_test_file_load($files) {
  foreach ($files as $file) {
    _file_test_log_call('load', array($file));
    // 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($file) {
  _file_test_log_call('validate', array($file));
  return _file_test_get_return('validate');
}

/**
 * Implementation of hook_file_download().
 */
function file_test_file_download($file) {
  _file_test_log_call('download', array($file));
  return _file_test_get_return('download');
}

/**
 * Implementation of hook_file_references().
 */
function file_test_file_references($file) {
  _file_test_log_call('references', array($file));
  return _file_test_get_return('references');
}

/**
 * Implementation of hook_file_insert().
 */
function file_test_file_insert($file) {
  _file_test_log_call('insert', array($file));
}

/**
 * Implementation of hook_file_update().
 */
function file_test_file_update($file) {
  _file_test_log_call('update', array($file));
}

/**
 * Implementation of hook_file_copy().
 */
function file_test_file_copy($file, $source) {
  _file_test_log_call('copy', array($file, $source));
}

/**
 * Implementation of hook_file_move().
 */
function file_test_file_move($file, $source) {
  _file_test_log_call('move', array($file, $source));
}

/**
 * Implementation of hook_file_delete().
 */
function file_test_file_delete($file) {
  _file_test_log_call('delete', array($file));
}