Redis Cache: implement compression

Install Redis service (daemon) on your Moodle server (see https://docs.moodle.org/37/en/Redis_cache_store#Installing_Redis_server ) if you do not already have it. Install the PHP extension Redis (see https://docs.moodle.org/37/en/Redis_cache_store#Installing_Redis_php_driver ) if you do not already have it. Start the Redis daemon (eg. redis-server /usr/local/etc/redis.conf ). Add the following to your config.php file define('TEST_CACHESTORE_REDIS_TESTSERVERS', '127.0.0.1'); Run the unit tests ie. vendor/bin/phpunit cache/stores/redis/tests/redis_test.php and vendor/bin/phpunit cache/stores/redis/tests/compressor_test.php .