Basicly the idea is to use a scenario with very different nations (by size, government, economical development). Neccessary is also that every nation has cities which differ by productivity, geographical location, etc).
Then set all buildings preq to no, so that AI can build only units or Capitalization. Also make sure that AI can discover only Future Technologies and disband virtually all units from the scenario. In events prohibit any negotiations.
The most time-consuming work is monitoring AI unit building choices during about 200 turns (checking it after every 5 turns). And doing it many times, changing few parameters every time (diplomatic relations between nations, technological levels - all technologies disovered, no technology discovered, adding key advances which can have impact to building choices like Trade, Gunpowder, Map Making etc). Actually I think that technologies have no impact to AI building choices - these tests can prove or disprove it.
Interaction between nations (unit losses during war, capturing cities, enemy units near cities, etc) needs special attention.
I use following unit rules:
@UNITS
Settlers, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Engineers, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Warriors, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Phalanx, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 0, nil, 000000000000000
Archers, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, nil, 000000000000000
Legion, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 2, nil, 000000000000000
Pikemen, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 3, nil, 000000000000000
Musketeers, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Fanatics, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Partisans, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Alpine Troops,nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 4, nil, 000000000000000
Riflemen, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 5, nil, 000000000000000
Marines, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 6, nil, 000000000000000
Paratroopers, nil, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 7, nil, 000000000000000
Mech. Inf., nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 0, nil, 000000000000000
Horsemen, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, nil, 000000000000000
Chariot, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 2, nil, 000000000000000
Elephant, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 3, nil, 000000000000000
Crusaders, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Knights, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Dragoons, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 4, nil, 000000000000000
Cavalry, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 5, nil, 000000000000000
Armor, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 6, nil, 000000000000000
Catapult, nil, 1, 1.,0, 1a, 1d, 1h,1f, 1,0, 7, nil, 000000000000000
Cannon, nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 0, nil, 000000000000000
Artillery, nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, nil, 000000000000000
Howitzer, nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 2, nil, 000000000000000
Fighter, nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 3, nil, 000000000000000
Bomber, nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 4, nil, 000000000000000
Helicopter, nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 5, nil, 000000000000000
Stlth Ftr., nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 6, nil, 000000000000000
Stlth Bmbr., nil, 2, 1.,0, 1a, 1d, 1h,1f, 1,0, 7, nil, 000000000000000
Trireme, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 0, nil, 000000000000000
Caravel, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, nil, 000000000000000
Galleon, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 2, nil, 000000000000000
Frigate, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 3, nil, 000000000000000
Ironclad, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 4, nil, 000000000000000
Destroyer, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 5, nil, 000000000000000
Cruiser, nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 6, nil, 000000000000000
AEGIS Cruiser,nil, 3, 1.,0, 1a, 1d, 1h,1f, 1,0, 7, nil, 000000000000000
Battleship, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Submarine, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Carrier, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Transport, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Cruise Msl., no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Nuclear Msl., no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Diplomat, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Spy, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Caravan, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Freight, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Explorer, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Rocket Launcer,no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
AA Battery, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
A-Defender, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Aerostat, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
SF-Battleship,no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Lasertroopers,no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Light Walker, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Heavy Walker, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Energy Shield,no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Space Fighter,no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
Space Bomber, no, 0, 1.,0, 1a, 1d, 1h,1f, 1,0, 1, no, 000000000000000
All units have the same stats in order to equalize all chances. There is only one unit for each type (domains 0-3 and roles 0-7) available. All other units are no,no including units which occupy special slots.
Actually all slots are "special" in aspect of building probability. I'm making now a matrix what will help to rule out the "slot factor" from final results.
It seems complicated and long but you are able to see most of the rules what govern AI building choices quite fast and rest of the work is simply for giving credibility to your results.
