It requires a separate download. Think its ~8GB in size. Characters you create are given 10k certs to play around with and they seem to update it quite regularly with new features. Almost everything that was in GU07 was on the Test Server first for like a week. http://forums.station.sony.com/ps2/...nder-ps2-test-server-is-now-available.114569/
What you have to do is buy all the chassis lights, as well as all the golden pistols. If you don't already have the engineer AV turret, you will need to buy that as well. After you have those things, put the cyan chassis lights on your Flash, switch to engineer (make sure you have the AV turret equipped!) and drive to the empty buildings just north of Howling Pass Checkpoint. Bring a friend with an S-AMS Sunderer, for a spawn point. One you get there, you will notice that one of these buildings looks different from all the other buildings in the game. It's locked up, but if you look through the windows on the doors, you'll notice a BFR (the mechs from PS1) inside. You need to get inside the building, but the doors are locked. To get inside, have your friend deploy the S-AMS Sunderer, and then walk around to the west side of the building. Have him climb up onto the mid-portion of the building, and walk into the wall while crouching. The collision detection is messed up here, so if he does it right, he should have crouched into an invisible wall and will be hugging the building, but will be trapped and will be unable to stop hugging the wall. Tell him to sit still, and then drive your Flash over there. Now, it helps if your friend is already damaged for this part to work correctly. Place an AV turret facing the Flash, and then shoot your friend until he only has a sliver of health left. Get in the AV turret and shoot the Flash. If you're lucky, some of the debris may fly off and hit your friend, killing him. This will be recognized as a sacrifice to the BFR gods, and the doors will unlock. If it fails, get another Flash and try again. If you accidentally kill your friend in some way besides hitting him with Flash debris, he can just spawn on the S-AMS Sunderer. After you succeed, go inside and get in the BFR. You're almost there, don't worry. Take the BFR to the Crown if it's controlled by the enemy. If your faction controls the Crown, wait until the enemy captures it. Anyway, take the BFR to the Crown when it is controlled by the enemy, and kill everyone there. After you've locked them all into their spawn point, press "5" on your keyboard. This will select the special BFR-only weapon that destroys spawn points. Aim it at the spawn point and it will get completely obliterated, destroying the Crown forever. After that, a wormhole should appear, taking you to the Test Server. Make sure you have the Golden Pistol equipped as you cannot pass through the wormhole without one. Good luck!
Browse a little in this thread. It's in the very same Forum you posted this in. http://forums.station.sony.com/ps2/index.php?threads/public-test-server-is-active.114080/