Add Phyrexian Arena

lib/magic/cards/phyrexian_arena.rb

@@ -0,0 +1,27 @@
+module Magic
+  module Cards
+    PhyrexianArena = Card("Phyrexian Arena") do
+      cost generic: 1, black: 2
+      type "Enchantment"
+    end
+
+    class PhyrexianArena < Card
+      class BeginningOfUpkeepTrigger < TriggeredAbility
+        def should_perform?
+          you?
+        end
+
+        def call
+          actor.trigger_effect(:draw_cards, source: actor)
+          actor.trigger_effect(:lose_life, target: controller, life: 1)
+        end
+      end
+
+      def event_handlers
+        {
+          Events::BeginningOfUpkeep => BeginningOfUpkeepTrigger
+        }
+      end
+    end
+  end
+end

lib/magic/events/beginning_of_upkeep.rb

@@ -1,6 +1,12 @@
 module Magic
   module Events
     class BeginningOfUpkeep
+      attr_reader :player
+
+      def initialize(player:)
+        @player = player
+      end
+
       def inspect
         "#<Events::BeginningOfUpkeep>"
       end

lib/magic/game/turn.rb

@@ -24,7 +24,7 @@ class Turn
 
         after_transition to: :upkeep do |turn|
           turn.notify!(
-            Events::BeginningOfUpkeep.new
+            Events::BeginningOfUpkeep.new(player: turn.active_player)
           )
         end
 

spec/cards/phyrexian_arena_spec.rb

@@ -0,0 +1,21 @@
+require 'spec_helper'
+
+RSpec.describe Magic::Cards::PhyrexianArena do
+  include_context "two player game"
+
+  subject! { ResolvePermanent("Phyrexian Arena", owner: p1) }
+
+  context "at the beginning of your upkeep" do
+    it "loses a life, draws a card" do
+      turn_1 = game.current_turn
+
+      turn_1.untap!
+
+      expect(p1.life).to eq(20)
+      turn_1 = game.current_turn
+      expect(p1).to receive(:draw!)
+      turn_1.upkeep!
+      expect(p1.life).to eq(19)
+    end
+  end
+end