D7: programmatically create block

custom_block.php

<?php

/**
 * Implements hook_block_info();
 */
function hook_block_info() {
  $blocks['test'] = array(
    'info' => t('Description'),
    'cache' => DRUPAL_NO_CACHE,
  );

  return $blocks;
}

/**
 * Implements hook_block_view().
 */
function hook_block_view($delta) {
  // Block view only "test".
   if ($delta != 'test') {
       return;
   }

   $block = array(
     'title' => t('Title'),
     'content' => 'Test',
   );

   return $block;
 }