Tic Tac Toe pairing with @kmeister2000

tictactoe.rb

class TicTacToe

  SIZE = 3

  def initialize
    @board = []
    SIZE.times do
      row = []
      SIZE.times do
        row << nil
      end
      @board << row
    end
  end

  def play(mark)
    @mark = mark
    self
  end

  def at(x, y)
    if x < 0 || x > SIZE-1  || y < 0 || y > SIZE-1
       raise GameRangeError
    else
      if @board[x][y].nil?
        @board[x][y] = @mark
        true
      else
        false
      end
    end
  end

  def winner
    @board.each do |e|
     if e.all? {|r| r == 'X'}
       return 'X'
     end
    end
    return nil
  end
end

class GameRangeError < Exception; end

tictactoe_spec.rb

require 'rspec'
require './tictactoe'

# Observations
#   TDD is not substitue for lack of domain knowledge
#   Brittle because based on string... instead of class?  Or Constant?

# Tic Tac Toe is a game
#   where there is a 3x3 board of blank spaces
#   and players take turns filling the spaces with their marks
#   players cannot play in an occupied space
#   if a player gets three of the same mark in a column, row or diagonal, they win
#   if all spaces are filled but no winner exists, the cat wins

describe "Tic Tac Toe" do
  let(:game) { TicTacToe.new }

  it "does not allow you to play outside of a 3x3 board" do
    expect { game.play('X').at( 1, 3)}.to raise_error(GameRangeError)
    expect { game.play('X').at( 3, 1)}.to raise_error(GameRangeError)
    expect { game.play('X').at( -1, 1)}.to raise_error(GameRangeError)
    expect { game.play('X').at( 1, -1)}.to raise_error(GameRangeError)
  end

  it "allows you to play inside of the 3x3 board" do
    game.play('X').at(1, 1).should be_true
  end

  it "does not allow you to play in a marked space" do
    game.play('X').at(1,1)
    game.play('X').at(1,1).should be_false
  end

  describe "winning" do
    it "wins if the same mark is all in the same row" do
      game.winner.should be_nil

      game.play('X').at(1, 0)
      game.play('X').at(1, 1)
      game.play('X').at(1, 2)

      game.winner.should == 'X'
    end

  end

end