1/ install moodle (without debug mode) 2/ run phpunit init and then all tests 3/ run behat init and then all tests 4/ set config.php setting $CFG->alternative_component_cache = 'somepath/core_component.php'; and verify it is created automatically if directory writable 5/ try all CLI options from "php admin/cli/alternative_component_cache.php" 6/ alter you alternative core_component.php file - some whitespace that does not create PHP error 7/ verify normal pages still work fine (because they do not validate the cache) 8/ verify admin/index.php page shows error that the cache file is stale 9/ execute "php admin/cli/alternative_component_cache.php --rebuild" and verify the core_component.php file is fixed again