Variable Sized ASCII Chess Board

chess_board.rb

class ChessBoard
  attr_accessor :rows, :columns, :square_size

  def initialize(rows, columns, square_size)
    @rows = rows
    @columns = columns
    @square_size = square_size
  end

  def render
    puts border_top, board, border_bottom
  end

  private

  def border_top
    "⌈#{'-' * columns * square_size}⌉"
  end

  def border_bottom
    "⌊#{'-' * columns * square_size}⌋"
  end

  def board
    (1..rows).map do |row_num|
      row(row_num)
    end.join
  end

  def row(row_num)
    content = (1..columns).map do |col_num|
      cell(row_num, col_num)
    end.join
    "|#{content}|\n" * square_size
  end

  def cell(row_num, col_num)
    fill = same_parity?([row_num, col_num]) ? '#' : ' '
    fill * square_size
  end

  def same_parity?(numbers)
    numbers.all?(&:odd?) || numbers.all?(&:even?)
  end
end

chess_board_spec.rb

require 'rspec'
require './chess_board'

describe ChessBoard do
  subject { described_class.new(8, 8, 3).render }

  expected_output = <<~OUTPUT
    ⌈------------------------⌉
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |###   ###   ###   ###   |
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    |   ###   ###   ###   ###|
    ⌊------------------------⌋
  OUTPUT

  it 'outputs the expected output' do
    expect { subject }.to output(expected_output).to_stdout
  end
end