Add Short Sword

Fixes #247

lib/magic/card_builder.rb

@@ -24,6 +24,10 @@ def Artifact(name, &block)
       Card(name, Magic::Cards::Artifact, &block)
     end
 
+    def Equipment(name, &block)
+      Card(name, Magic::Cards::Equipment, &block)
+    end
+
     def Card(name, base_class = Magic::Card, &block)
       card = Class.new(base_class, &block)
       card.const_set(:NAME, name)

lib/magic/cards/equipment.rb

@@ -0,0 +1,62 @@
+module Magic
+  module Cards
+    class Equipment < Card
+      TYPE_LINE = "Artifact -- Equipment"
+
+
+      def self.equip(cost)
+        equip = Class.new(ActivatedAbility) do
+          def costs
+            [Costs::Mana.new(generic: 1)]
+          end
+
+          def target_choices
+            game.battlefield.creatures.controlled_by(controller)
+          end
+
+          def resolve!(target:)
+            target.attachments << source
+          end
+        end
+
+        define_method(:activated_abilities) do
+          [equip]
+        end
+      end
+
+      def resolve!(target:)
+        permanent = super()
+        permanent.attach_to!(target)
+      end
+
+      def single_target?
+        true
+      end
+
+      def resolve!(target:)
+        permanent = super()
+        permanent.attach_to!(target)
+      end
+
+      def power_modification
+        0
+      end
+
+      def toughness_modification
+        0
+      end
+
+      def keyword_grants
+        []
+      end
+
+      def type_grants
+        []
+      end
+
+      def can_activate_ability?(_)
+        true
+      end
+    end
+  end
+end

lib/magic/cards/short_sword.rb

@@ -0,0 +1,17 @@
+module Magic
+  module Cards
+    ShortSword = Equipment("Short Sword") do
+      cost generic: 1
+
+      equip 1
+
+      def power_modification
+        1
+      end
+
+      def toughness_modification
+        1
+      end
+    end
+  end
+end

spec/cards/short_sword_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+RSpec.describe Magic::Cards::ShortSword do
+  include_context "two player game"
+
+  subject(:permanent) { ResolvePermanent("Short Sword") }
+
+  context "equips, gives a +1/+1" do
+    let!(:wood_elves) { ResolvePermanent("Wood Elves", owner: p1) }
+
+    it "buffs wood elves" do
+      p1.add_mana(white: 1)
+      p1.activate_ability(ability: permanent.activated_abilities.first) do
+        _1.targeting(wood_elves)
+        _1.pay_mana(generic: { white: 1 })
+      end
+
+      expect(wood_elves.attachments.count).to eq(1)
+      expect(wood_elves.attachments.first.name).to eq("Short Sword")
+      expect(wood_elves.power).to eq(2)
+      expect(wood_elves.toughness).to eq(2)
+    end
+  end
+end