Shows you how much money you're wasting in this meeting.

clock.rb

require 'rspec'

class Clock
  def initialize(minutes = 0)
    @minutes = minutes
    @cost = 0
  end

  def work_days; 22 end
  def average_salary; 4000.0 end
  def work_hours; 8 end

  def hourly_rate(person = 1)
    (average_salary/work_days/work_hours) * person
  end

  def minute_rate(person = 1)
    (hourly_rate/60) * person
  end

  def running_cost(person)
    (minute_rate(person) * @minutes).round(2)
  end

  def minutes; @minutes end

  def tick
    @minutes+=1
  end

  def self.start(person)
    clock = Clock.new
    while true do
      system 'clear'
      puts "We've been here for #{clock.minutes} minutes and it has cost us $#{clock.running_cost(person)}"
      clock.tick
      sleep 60
    end
  end
end

# Clock.start 1

describe Clock do
  it 'assumes that there are 22 working days in a month' do
    subject.work_days.should == 22
  end

  it 'assumes that the average salary is 4000 a month' do
    subject.average_salary.should == 4000.0
  end

  it 'assumes that people work for 8 hours a day' do
    subject.work_hours.should == 8
  end

  it 'computes how much a person earns per hour' do
    subject.hourly_rate.should == hourly_rate
  end

  it 'computes how much this meeting costs given 1 person' do
    subject.minute_rate(1).should == minute_rate
  end

  it 'computes how much this meeting costs given 2 person' do
    subject.minute_rate(2).should == (minute_rate) * 2
  end

  it 'knows the running cost given the # of minutes given 1 persons' do
    Clock.new(5).running_cost(1).should == (minute_rate * 1 * 5).round(2)
  end

  it 'knows the running cost given the # of minutes given 2 persons' do
    Clock.new(5).running_cost(2).should == (minute_rate * 2 * 5).round(2)
  end

  def hourly_rate
    4000.0/22/8
  end

  def minute_rate
    hourly_rate/60
  end
end