Merge pull request #510 from dNitza/add-rhystic-study

Rhystic Study

lib/magic/cards/rhystic_study.rb

@@ -0,0 +1,51 @@
+module Magic
+  module Cards
+    RhysticStudy = Enchantment("Rhystic Study") do
+      type "Enchantment"
+      cost generic: 2, blue: 1
+    end
+
+    class RhysticStudy < Enchantment
+      class Choice < Magic::Choice
+        attr_reader :owner, :caster
+
+        def initialize(owner:, caster:)
+          @owner = owner
+          @caster = caster
+        end
+
+        def costs
+          @costs ||= [Costs::Mana.new(generic: 1)]
+        end
+
+        def pay(player:, payment:)
+          cost = costs.first
+          cost.pay!(player:, payment:)
+        end
+
+        def resolve!
+          if !costs.all?(&:paid?)
+            owner.draw!
+          end
+        end
+      end
+
+      # Whenever an opponent casts a spell,
+      # you may draw a card unless that player pays {1}
+      def event_handlers
+        {
+          Events::SpellCast => ->(receiver, event) do
+            return if event.player == receiver.controller
+
+            game
+              .choices
+              .add(
+                Magic::Cards::RhysticStudy::Choice.new(owner: receiver.controller,
+                  caster: event.player)
+              )
+          end
+        }
+      end
+    end
+  end
+end

spec/cards/rhystic_study_spec.rb

@@ -0,0 +1,61 @@
+require "spec_helper"
+
+RSpec.describe Magic::Cards::RhysticStudy do
+  include_context "two player game"
+
+  let!(:rhystic_study) { ResolvePermanent("Rhystic Study", owner: p1) }
+
+  context "when opponent casts spell" do
+    let!(:wood_elves_1) { Card("Wood Elves") }
+
+    it "p2 casts 1 wood elf, p2 doesn't pay the 1, p1 draws" do
+      expect(p1).to receive(:draw!)
+      p2.add_mana({green: 4})
+      p2.cast(card: wood_elves_1) do
+        _1.pay_mana(generic: {green: 2}, green: 1)
+      end
+
+      choice = game.choices.first
+      expect(choice).to be_a(Magic::Cards::RhysticStudy::Choice)
+      game.resolve_choice!
+    end
+
+    it "p1 casts 1 wood elf, Rhystic Study doesn't trigger" do
+      expect(p1).to_not receive(:draw!)
+      p1.add_mana({green: 4})
+      p1.cast(card: wood_elves_1) do
+        _1.pay_mana(generic: {green: 2}, green: 1)
+      end
+
+      choice = game.choices.first
+      expect(choice).to be_nil
+    end
+
+    it "p2 casts 1 wood elf, p2 pays the 1, p1 doesn't draws" do
+      expect(p1).to_not receive(:draw!)
+      p2.add_mana({green: 4})
+      p2.cast(card: wood_elves_1) do
+        _1.pay_mana(generic: {green: 2}, green: 1)
+      end
+
+      choice = game.choices.first
+      expect(choice).to be_a(Magic::Cards::RhysticStudy::Choice)
+      choice.pay(player: p2, payment: {generic: {green: 1}})
+      choice.resolve!
+    end
+
+    it "p2 casts 1 wood elf, p2 tries to pay 3, which is not allowed" do
+      expect {
+        expect(p1).to_not receive(:draw!)
+        p2.add_mana({green: 7})
+        p2.cast(card: wood_elves_1) do
+          _1.pay_mana(generic: {green: 2}, green: 1)
+        end
+
+        choice = game.choices.first
+        expect(choice).to be_a(Magic::Cards::RhysticStudy::Choice)
+        choice.pay(player: p2, payment: {generic: {green: 3}})
+      }.to raise_error(Magic::Costs::Mana::Overpayment)
+    end
+  end
+end