game_of_life_spec.rb

describe 'Game of life w/o primitives and one dot per line' do
  let(:live_cell) { LiveCell.new }
  let(:dead_cell) { DeadCell.new }

  context 'live cell' do
    it 'dies with less than 2 neighbours' do
      alive_cells = Neighbours.new(LiveCell.new)
      expect(live_cell.next(alive_cells)).to be_a_kind_of DeadCell
    end

    it 'lives with 2 neighbours' do
      alive_cells = Neighbours.new(LiveCell.new, LiveCell.new)

      expect(live_cell.next(alive_cells)).to be_a_kind_of LiveCell
    end

    # it 'dies with more than 3 neighbours' do
    #   expect(live_cell.next(5)).to be_a_kind_of DeadCell
    # end
  end

  # context 'dead cell' do
  #   it 'lives with 3 neighbours' do
  #     expect(dead_cell.next(3)).to be_a_kind_of LiveCell
  #   end
  # end
end

class Neighbours
  def initialize(*neighbours)
    @neighbours = neighbours
  end
end

class LiveCell
  def next(neighbours)
    if neighbours.size == 2 || neighbours.size == 3
      LiveCell.new
    else
      DeadCell.new
    end
  end
end

class DeadCell
  def next(neighbours)
    if neighbours.size == 3
      LiveCell.new
    else
      DeadCell.new
    end
  end
end

apuntes de + ideas:

• hashmap de 'rules' (clave de colección y key del resultado)
• excepciones como ceros/null/muerte