The most-likely beta-test server
test (without capitalization) is a server on Lunaria Story, most presumably to be a beta-testing server for creators. Some may or may not consider this a server.
Unlike the main servers, if you click on test when tryign to play, you will be lead to a new tab/window allowing you to play the game, like any other server, but you will only see this message;
All Lunaria Story servers are currently undergoing maintenance. Downtime servers will be 1-2 hours.