Add Hunter's Edge

lib/magic/cards/hunters_edge.rb

@@ -0,0 +1,35 @@
+module Magic
+  module Cards
+    HuntersEdge = Sorcery("Hunter's Edge") do
+      cost generic: 3, green: 1
+
+      def multi_target? = true
+
+      def target_choices
+        [
+          battlefield.creatures.controlled_by(controller),
+          battlefield.creatures.not_controlled_by(controller),
+        ]
+      end
+
+      def resolve!(targets:)
+        first_creature, second_creature = targets
+
+        trigger_effect(
+          :add_counter,
+          target: first_creature,
+          counter_type: "+1/+1",
+        )
+
+        game.tick!
+
+        trigger_effect(
+          :deal_damage,
+          source: first_creature,
+          target: second_creature,
+          damage: first_creature.power,
+        )
+      end
+    end
+  end
+end

spec/cards/hunters_edge_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Magic::Cards::HuntersEdge do
+  include_context "two player game"
+
+  let!(:wood_elves) { ResolvePermanent("Wood Elves", owner: p1) }
+  let!(:alpine_watchdog) { ResolvePermanent("Alpine Watchdog", owner: p2) }
+
+  let(:hunters_edge) { Card("Hunter's Edge") }
+
+  it "puts a +1/+1 counter on your creature, then it deals damage equal to its new power to opponent's creature" do
+    p1.add_mana(green: 4)
+    p1.cast(card: hunters_edge) do
+      _1.targeting(wood_elves, alpine_watchdog)
+      _1.pay_mana(green: 1, generic: { green: 3 })
+    end
+    game.stack.resolve!
+    game.tick!
+
+    expect(wood_elves.power).to eq(2)
+    expect(wood_elves.toughness).to eq(2)
+    expect(alpine_watchdog.damage).to eq(2)
+  end
+
+  it "only allows targeting your creature first and an opponent's creature second" do
+    p1.hand.add(hunters_edge)
+    cast = p1.prepare_cast(card: hunters_edge)
+    expect(cast.target_choices[0]).to include(wood_elves)
+    expect(cast.target_choices[0]).not_to include(alpine_watchdog)
+    expect(cast.target_choices[1]).to include(alpine_watchdog)
+    expect(cast.target_choices[1]).not_to include(wood_elves)
+  end
+end