Test Problem

urinal_etiquette.rb

class Ptest
  def initialize(stalls)
    @stalls = Array.new(stalls).map { |s| s = false }
  end
  
  def stalls
    @stalls
  end
    
  def empty?
    is_occupied = false
    @stalls.each do |s|
      is_occupied = is_occupied || s
    end    
    ! is_occupied
  end
  
  def furthest_available
    return (@stalls.size - 1) if empty?
    (@stalls.size - 2).downto(0).each do |s|
      next if @stalls[s] || @stalls[s + 1]
      return s
    end
  end
  
  def add_occupant
    furthest = self.furthest_available
    @stalls[furthest] = true
    furthest
  end
end

urinal_etiquette_test.rb

require 'rspec'
require File.expand_path('.', 'urinal_etiquette')

describe Ptest do

  before do
    @size = 6
    @ptest = Ptest.new(@size)
  end

  context '#initialize' do
    it "should be the right length" do
      @ptest.stalls.size.should eq(@size)
    end

    it "should be 'empty'" do
      @ptest.empty?.should eq(true)
    end
    
  end
  
  context 'rule 1: Furthest from the door' do
    it "should be furthest from the door" do
      @ptest.furthest_available.should eq(@size-1)
    end
    
    context "adding one occupant" do
      it "should place the occupant furtherest from the door" do
        @ptest.add_occupant.should eq(@size - 1)
      end
    end
  end
  context "rule 2: Don't stand next to a dude" do
    before do
      @ptest.add_occupant
    end
    
    it "should properly place a new dude" do
      @ptest.add_occupant.should eq(@size - 3)
    end

    context "with a full restroom" do
      it "should return nil" do
        @ptest.add_occupant
        @ptest.add_occupant.should eq(nil)
      end
    end
  end
end