MobLab games have two modes: Test Mode and Game Mode. Games played in Test Mode are not counted towards students' earnings, whereas games played in Game Mode are.
Use Test Mode to give students a practice round without performance counting against them.
To switch between Game Mode and Test Mode, simply open the game panel and click on the icon next to the cross. The beaker means the game is in Test Mode. The game pad means the game is in Game Mode.
You can always change a game's mode, even after the game has been played.