The test game means a non competitive game (or mostly non competitive) where we are using 2-3 minute turns and the players are asked not to completely kill of other players. The purpose of the test game is testing the ruleset and finding errors. If I have changed something, that may not alwasy work as intended and the test games are a great way of figuring out that kind of issues.
If you join a test game but don't have time to play, that's not an issue since a test game is for testing only
