Game of life implementation

gol.rb

class World
  attr_accessor :cells

  def initialize
    @cells = []
  end

  def push_cell cell
    @cells = @cells << cell
  end
end

class Cell
  attr_accessor :state, :x, :y, :world, :neighbour_count

  def initialize(x,y,state,world)
   @x = x
   @y = y
   @neighbour_count = 0
   @state = state
   @world = world
   @world.push_cell self
  end

  def all_minus_self
    cells_minus_self = world.cells - [self]
  end

  def coords
    [@x,@y]
  end

  def more_than_three(neighbour_count)
    neighbour_count > 3
  end

  def less_than_two(neighbour_count)
    neighbour_count < 2
  end

  def count_neighbors
    check_loop
    @neighbour_count
  end

  def check_for_neighbours
    the_neighbour_count = count_neighbors

    while (more_than_three the_neighbour_count) || (less_than_two neighbour_count)
      return @state = false
    end

    @state = true
  end

  def self.is_neighbour(cell, target, x_range, y_range)
    (cell.x + x_range == target.x) && (cell.y + y_range == target.y)
  end

  def check_loop
    all_minus_self.each do |cell|
      (-1..1).each do |x_range|
        (-1..1).each do |y_range|
          (Cell.is_neighbour(cell, self, x_range, y_range)) ? (@neighbour_count += 1) : nil
        end
      end
    end
  end
end

gol_spec.rb

require 'rspec'
require_relative '../cell.rb'

describe Cell do
  it 'initializes with coords and a state' do
    cell = Cell.new(0,0,true,World.new)
    expect(cell.state).to eq true
    expect(cell.coords).to eq [0,0]
  end

  it 'dies when there are greater than 3 cells adjacent to it' do
    world = World.new
    cell = Cell.new(1,2,true,world)
    Cell.new(2,3,true,world)
    Cell.new(1,3,true,world)
    Cell.new(0,1,true,world)
    Cell.new(2,2,true,world)
    cell.check_for_neighbours
    expect(cell.state).to eq false
  end

  it 'dies when there are less than 2 cells adjacent to it' do
    world = World.new
    cell = Cell.new(1,2,true,world)
    Cell.new(2,3,true,world)
    cell.check_for_neighbours
    expect(cell.state).to eq false
  end

  it "carries on if there are 2 or 3 neighbours adjacent to it" do
    world = World.new
    cell = Cell.new(1,2,true,world)
    Cell.new(2,3,true,world)
    Cell.new(1,3,true,world)
    Cell.new(0,1,true,world)
    cell.check_for_neighbours
    expect(cell.state).to eq true
  end

end