activitypub-1.0.x-dev/tests/modules/activitypub_test/activitypub_test.module

<?php

/**
 * @file
 * ActivityPub test module.
 */

/**
 * Debug dump helper function.
 *
 * @param $var
 * @param string $filename
 */
function activitypub_test_dump_debug($var, string $filename = 'debugging') {
  file_put_contents($filename, $var . "\n", FILE_APPEND);
}