Refactor Golgari Guildgate

lib/magic/cards/golgari_guildgate.rb

@@ -9,23 +9,8 @@ def enters_tapped?
         true
       end
 
-      class ManaAbility < Magic::ManaAbility
-        def initialize(source:)
-          @costs = [Costs::Tap.new(source)]
-
-          super
-        end
-
-        def resolve!
-          game.add_effect(
-            Effects::AddManaOrAbility.new(
-              source: source,
-              player: source.controller,
-              black: 1,
-              green: 1
-            )
-          )
-        end
+      class ManaAbility < Magic::TapManaAbility
+        choices :black, :green
       end
 
       def activated_abilities = [ManaAbility]

spec/cards/golgari_guildgate_spec.rb

@@ -16,11 +16,9 @@
   end
 
   it "taps for either black or green" do
-    p1.activate_ability(ability: permanent.activated_abilities.first) do
-      _1.pay_tap
+    p1.activate_mana_ability(ability: permanent.activated_abilities.first) do
+      _1.choose(:black)
     end
-    game.resolve_pending_effect(black: 1)
-    expect(game.effects).to be_empty
     expect(p1.mana_pool[:black]).to eq(1)
   end
 end