John Cleary (@TheRealBifter) is doing a nice project -
The 12 TDD's of Xmas.
Day 11 was Poker Hands. I did it in Ruby. Here's the code from traffic-light 116.
Tests first:
require './card'
require './hand'
require 'test/unit'
class TestUntitled < Test::Unit::TestCase
def test_start
hand = Hand.new("2H 4S 4C 2D 4H")
assert_equal Card.new('2',:hearts), hand[0]
assert_equal Card.new('4',:spades), hand[1]
assert_equal Card.new('4',:clubs), hand[2]
assert_equal Card.new('2',:diamonds), hand[3]
assert_equal Card.new('4',:hearts), hand[4]
end
def test_card_has_pips_and_suit_set_on_creation
card = Card.new('2',:hearts)
assert_equal '2', card.pips
assert_equal :hearts, card.suit
card = Card.new('T',:hearts)
assert_equal 'T', card.pips
assert_equal :hearts, card.suit
card = Card.new('J',:hearts)
assert_equal 'J', card.pips
assert_equal :hearts, card.suit
card = Card.new('Q',:hearts)
assert_equal 'Q', card.pips
assert_equal :hearts, card.suit
card = Card.new('K',:hearts)
assert_equal 'K', card.pips
assert_equal :hearts, card.suit
card = Card.new('A',:hearts)
assert_equal 'A', card.pips
assert_equal :hearts, card.suit
end
def test_hand_ranked_three_of_a_kind
assert_equal :three_of_a_kind, Hand.new("2H 4S 4C AD 4H").rank
end
def test_hand_ranked_one_pair
assert_equal :one_pair, Hand.new("2H 4S 5C JD 4H").rank
end
def test_hand_ranked_two_pairs
assert_equal :two_pairs, Hand.new("2H 4S 5C 2D 4H").rank
end
def test_hand_ranked_flush
assert_equal :flush, Hand.new("2H 4H 6H 8H TH").rank
end
def test_hand_ranked_straight
assert_equal :straight, Hand.new("2H 3C 4H 5H 6H").rank
end
def test_hand_ranked_full_house
assert_equal :full_house, Hand.new("2H 4S 4C 2D 4H").rank
end
def test_hand_ranked_four_of_a_kind
assert_equal :four_of_a_kind, Hand.new("2H 4S 4C 4D 4H").rank
end
def test_hand_ranked_straight_flush
assert_equal :straight_flush, Hand.new("2H 4H 3H 5H 6H").rank
end
def test_hand_ranked_high_card
assert_equal :high_card, Hand.new("2C 3H 4S 8C AH").rank
end
def test_full_house_beats_flush
black = Hand.new("2H 4S 4C 2D 4H")
white = Hand.new("2S 8S AS QS 3S")
assert_equal 1, black <=> white
end
def test_higher_card_wins_if_equal_rank
black = Hand.new("2H 3D 5S 9C KD")
assert_equal :high_card, black.rank
white = Hand.new("2C 3H 4S 8C AH")
assert_equal :high_card, white.rank
assert_equal -1, black <=> white
end
def test_equal_hands
black = Hand.new("2H 3D 5S 9C KD")
assert_equal :high_card, black.rank
white = Hand.new("2D 3H 5C 9S KH")
assert_equal :high_card, white.rank
assert_equal 0, black <=> white
end
end
Code second:
class Hand
def initialize(cards)
@cards =
cards.gsub(/\s+/, "")
.scan(/.{2}/)
.map{|ch| Card.new(ch[0],suit(ch[1]))}
end
def [](n)
return @cards[n]
end
def rank
return :straight_flush if straight? && flush?
return :flush if flush?
return :straight if straight?
pip_tallies = pip_counts.sort.reverse
return {
[4,1] => :four_of_a_kind,
[3,2] => :full_house,
[3,1] => :three_of_a_kind,
[2,2] => :two_pairs,
[2,1] => :one_pair,
[1,1] => :high_card
}[pip_tallies[0..1]]
end
def <=>(other)
keys <=> other.keys
end
def keys
[ranking,pip_counts]
end
private
def ranking
ranks.index(rank)
end
def ranks
[
:high_card,
:pair,
:two_pairs,
:three_of_a_kind,
:straight,
:flush,
:full_house,
:four_of_a_kind,
:straight_flush
]
end
def pip_counts
"23456789TJQKA"
.chars
.collect {|pips| pip_count(pips)}
end
def pip_count(pips)
@cards.count{|card| card.pips == pips}
end
def pip_flags
pip_counts.map{|n| n > 0 ? 'T' : 'F'}.join
end
def straight?
pip_flags.include? 'TTTTT'
end
def flush?
suit_counts.any?{|n| n == 5}
end
def suit_counts
suits.collect{|suit| suit_count(suit)}
end
def suits
[:clubs,:diamonds,:hearts,:spades]
end
def suit_count(suit)
@cards.count{|card| card.suit == suit}
end
def suit(ch)
return suits["CDHS".index(ch)]
end
end
class Card
def initialize(pips,suit)
@pips,@suit = pips,suit
end
def ==(other)
pips == other.pips && suit == other.suit
end
def pips
@pips
end
def suit
@suit
end
end
You can
replay my entire progression (warts and all) on Cyber-Dojo (naturally).
is an excellent book by Eugen Herrigel (isbn 978-0-14-019074-8). As usual I'm going to quote from a few pages:
