Add Ranger's Guile

lib/magic/cards/rangers_guile.rb

@@ -0,0 +1,23 @@
+module Magic
+  module Cards
+    RangersGuile = Instant("Ranger's Guile") do
+      cost green: 1
+    end
+
+    class RangersGuile < Instant
+      def single_target?
+        true
+      end
+
+      def target_choices
+        controller.creatures
+      end
+
+      def resolve!(target:)
+        target.modify_power(1)
+        target.modify_toughness(1)
+        target.grant_hexproof!
+      end
+    end
+  end
+end

spec/cards/rangers_guile_spec.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Magic::Cards::RangersGuile do
+  include_context "two player game"
+
+  let!(:wood_elves) { ResolvePermanent("Wood Elves", owner: p1) }
+
+  it "gives target creature you control +1/+1 and hexproof until end of turn" do
+    p1.add_mana(green: 1)
+    p1.cast(card: Card("Ranger's Guile")) do
+      _1.auto_pay_mana
+      _1.targeting(wood_elves)
+    end
+
+    game.stack.resolve!
+    game.tick!
+
+    expect(wood_elves.power).to eq(2)
+    expect(wood_elves.toughness).to eq(2)
+    expect(wood_elves.hexproof?).to eq(true)
+    expect(wood_elves.keyword_grant_modifiers.first.until_eot?).to eq(true)
+  end
+
+  it "the +1/+1 boost and hexproof wear off after end of turn" do
+    p1.add_mana(green: 1)
+    p1.cast(card: Card("Ranger's Guile")) do
+      _1.auto_pay_mana
+      _1.targeting(wood_elves)
+    end
+
+    game.stack.resolve!
+    game.tick!
+
+    expect(wood_elves.power).to eq(2)
+    expect(wood_elves.toughness).to eq(2)
+    expect(wood_elves.hexproof?).to eq(true)
+
+    game.current_turn.end!
+    game.current_turn.cleanup!
+    game.next_turn
+    game.tick!
+
+    expect(wood_elves.power).to eq(1)
+    expect(wood_elves.toughness).to eq(1)
+    expect(wood_elves.hexproof?).to eq(false)
+  end
+end