Poker Kata

PokerKata.cs

using System.Collections.Generic;
using System.Linq;
using NUnit.Framework;

namespace PokerKata
{
    [TestFixture]
    public class describe_Hand
    {
        [Test]
        public void hand_of_nine_beats_8()
        {
            new Hand("9", "2").Beats(new Hand("8", "2")).Is(true);
        }

        [Test]
        public void hand_with_ace_king_beats_hand_with_ace_queen()
        {
            new Hand("5", "A").Beats(new Hand("9", "7")).Is(true);
        }

        [Test]
        public void hand_with_ace_queen_loses_to_hand_with_ace_king()
        {
            new Hand("A", "Q").Beats(new Hand("A", "K")).Is(false);
        }
    }
    [TestFixture]
    public class describe_Card
    {
        [Test]
        public void nine_beats_8()
        {
            new Card("9").Beats(new Card("8")).Is(true);
        }

        [Test]
        public void eight_doesnt_beat_9()
        {
            new Card("8").Beats(new Card("9")).Is(false);
        }

        [Test]
        public void king_beats_8()
        {
            new Card("K").Beats(new Card("8")).Is(true);
        }

        [Test]
        public void ace_beats_king()
        {
            new Card("A").Beats(new Card("K")).Is(true);
        }

        [Test]
        public void ace_value_is_14()
        {
            new Card("A").Rank.Is(14);
        }

        [Test]
        public void king_value_is_13()
        {
            new Card("K").Rank.Is(13);
        }
    }

    public class Hand
    {
        List<Card> Cards;

        public Hand(params string[] cards)
        {
            Cards = cards.Select(c => new Card(c)).OrderByDescending(c=>c.Rank).ToList();
        }

        int WeightedRank()
        {
            return Cards[0].Rank * 14 + Cards[1].Rank;
        }

        public bool Beats(Hand hand)
        {
            return WeightedRank() > hand.WeightedRank();
        }
    }

    public class Card
    {
        public int Rank;
        private Dictionary<string, int> map;

        public Card(string value)
        {
            CreateMap();
            Rank = map[value];
        }

        private void CreateMap()
        {
            map = new Dictionary<string, int>
                      {
                          {"1",1},
                          {"2",2},
                          {"3",3},
                          {"4",4},
                          {"5",5},
                          {"6",6},
                          {"7",7},
                          {"8",8},
                          {"9",9},
                          {"T",10},
                          {"J",11},
                          {"Q",12},
                          {"K",13},
                          {"A",14},
                      };
        }

        public bool Beats(Card card)
        {
            return Rank > card.Rank;
        }
    }
}

public static class Extensions
{
    public static void Is(this object actual, object expected)
    {
        Assert.AreEqual(expected, actual);
    }
}