Covenant

Covenant is a location and possible settlement in the Commonwealth in Fallout 4.

Appearances
Covenant only appears in Fallout 4.

Behind the scenes
The SAFE Test, the test to get into Covenant, is actually the G.O.A.T. test from Fallout 3 having all the questions except the last question, but a few have been modified.

This is also a pretty blatant reference to the Voight-Kampff test from Blade Runner/Do Androids Dream of Electric Sheep.

Settlement
It is possible to settle the Covenant if you complete the Human Error mission and side against the Covenant. Returning after completion will initiate a battle with the residents and settlers in which you can use the workshop once you emerge victorious. To emerge victorious you must destroy all the machine gun turrets and kill everyone except the cat.

In some cases, it has been reported that if you can avoid alerting the turrets and Deezer, you don't have to destroy them. Somehow get the townsfolk to chase after you outside their walls, and you can leave the turrets up, let the lemonade vendor serve on, and still access the workshop. You can't dismantle the turrets, and they don't count towards the defense score, but they ought to attack hostiles. (Need confirmation) You could also, at this point, just destroy them for a tiny bit of 5.56 ammo. Deezer cannot be moved to another settlement, and if killed, only drops flamer ammo.