Dogs are very smart, and, contrary to popular belief, you can teach an old dog new tricks. The Dog test is really a form of solitaire Magic. Take some of your extra basic lands (equal numbers of each type) and shuffle them together. Then choose one action to correspond with each land type. These actions can be anything you want; you can make the duel as easy or as challenging as you want by varying them, or make it simulate a particular type of deck. You can restrict the Dog to casting spells that fit his available mana, or you can ignore the mana entirely, or count the amount of available mana but ignore the color.

For example, you might pick:

Island: Dog does nothing now, but Counterspells the next spell you cast. The Counterspell costs no mana.

Swamp: If Dog has four or fewer lands, he plays a Will-O'-The-Wisp. Otherwise, he plays a Sengir Vampire.

Mountain: If Dog has three or fewer lands in play, he Lightning Bolts you. Otherwise, he hits you with a Disintegrate for as many points as he has lands.

Forest: If Dog has only one land, he plays a Scryb Sprite; if two lands, a Grizzly Bear; three lands, Land Leeches; four lands, Giant Spider; five lands, Durkwood Boars; six or more lands, Craw Wurm.

Plains: Dog plays a Circle of Protection for whichever color you're using most that isn't already protected against, or CoP: Artifacts if you have more artifact creatures than colored ones. (Pretend the casting cost is just if Dog has only one land.)

For this particular set of Dog rules, Dog must tap the appropriate number of lands for the casting cost of his spells, but ignores the color requirements for the creatures which need two or more of one color to summon.

Each time that it's Dog's turn, flip over the top card from the pile of lands and put it into play in Dog's territory. Dog then does whatever action you assigned to that land, and then attacks if it's profitable to do so. When you attack, Dog will defend and/or prevent the damage in the most effective way you can think of. (Dogs are smart, remember?)