Berlin clock kata implemented in ruby (http://content.codersdojo.org/code-kata-catalogue/berlin-clock/)

berlin_clock.rb

class BerlinClock
  SECONDS  = "Y"
  HOURS_FIVES = "RRRR"
  HOURS_ONES = "RRRR"
  MINUTES_FIVES = "YYRYYRYYRYY"
  MINUTES_ONES = "YYYY"

  def initialize(h,m,s)
    @h, @m, @s = h, m, s
  end

  def format(line, part, op, mod=5)
    on_count = part.public_send(op, mod)
    off_count = line.length - on_count
    line[0, on_count] + "O" * off_count
  end
  
  def seconds
    format(SECONDS, @s + 1, :%, 2)
  end

  def hours_fives
    format(HOURS_FIVES, @h, :/)
  end

  def hours_ones
    format(HOURS_ONES, @h, :%)
  end

  def minutes_ones
    format(MINUTES_ONES, @m, :%)
  end

  def minutes_fives
    format(MINUTES_FIVES, @m, :/)  
  end

  def to_s
    "#{seconds}\n#{hours_fives}\n#{hours_ones}\n#{minutes_fives}\n#{minutes_ones}"
  end 
end

berlin_clock_spec.rb

require './lib/berlin_clock'

describe BerlinClock do
  it 'midnight all lights are off, but Y' do
    clock = BerlinClock.new(0,0,0)
    expect(clock.to_s).to eq("Y\nOOOO\nOOOO\nOOOOOOOOOOO\nOOOO")
  end  

  it '1 second after midnight all lights are off' do
    clock = BerlinClock.new(0,0,1)
    expect(clock.to_s).to eq("O\nOOOO\nOOOO\nOOOOOOOOOOO\nOOOO")
  end  

  it '1 hour after midnight third row has 1 light on' do
    clock = BerlinClock.new(1,0,0)
    expect(clock.to_s).to eq("Y\nOOOO\nROOO\nOOOOOOOOOOO\nOOOO")
  end  

  it '2 hours after midnight third row has 2 light on' do
    clock = BerlinClock.new(2,0,0)
    expect(clock.to_s).to eq("Y\nOOOO\nRROO\nOOOOOOOOOOO\nOOOO")
  end  

  it '5 hours after midnight second row has 1 light on' do
    clock = BerlinClock.new(5,0,0)
    expect(clock.to_s).to eq("Y\nROOO\nOOOO\nOOOOOOOOOOO\nOOOO")
  end  
  
  it '6 hours after midnight second row has 1 light on and third has 1 light' do
    clock = BerlinClock.new(6,0,0)
    expect(clock.to_s).to eq("Y\nROOO\nROOO\nOOOOOOOOOOO\nOOOO")
  end  
  
  it '13 hours after midnight second row has 2 lights on and third has 3 lights' do
    clock = BerlinClock.new(13,0,0)
    expect(clock.to_s).to eq("Y\nRROO\nRRRO\nOOOOOOOOOOO\nOOOO")
  end  

  it '1 minute after midnight last row has 1 lights on' do
    clock = BerlinClock.new(0,1,0)
    expect(clock.to_s).to eq("Y\nOOOO\nOOOO\nOOOOOOOOOOO\nYOOO")
  end  

  it '5 minutes after midnight minutes row has 1 lights on' do
    clock = BerlinClock.new(0,5,0)
    expect(clock.to_s).to eq("Y\nOOOO\nOOOO\nYOOOOOOOOOO\nOOOO")
  end  

  it '13:17:01' do
    clock = BerlinClock.new(13,17,01)
    expect(clock.to_s).to eq("O\nRROO\nRRRO\nYYROOOOOOOO\nYYOO")
  end

  it '23:59:59' do
    clock = BerlinClock.new(23,59,59)
    expect(clock.to_s).to eq("O\nRRRR\nRRRO\nYYRYYRYYRYY\nYYYY")
  end

  it '24:00:00' do
    clock = BerlinClock.new(24,00,00)
    expect(clock.to_s).to eq("Y\nRRRR\nRRRR\nOOOOOOOOOOO\nOOOO")
  end

end