Test Problem

bathroom.rb

class Bathroom
  # door is on the right
  
  def initialize(params)
    @stalls = params[:stalls]
    @stall_ratings = rate_stalls
    @line = params[:line]
  end
  
  def find_stall
    return first_empty_stall if line? || (safe_stalls? && rules_broken?)
    return best_stall unless rules_broken?
    return nil if rules_broken? && no_safe_stalls?
  end
  
  private
  
  def line?
    @line
  end
  
  def rules_broken?
    @stall_ratings.index(2)
  end

  def safe_stalls?
    @stall_ratings.index(0)    
  end
  
  def no_safe_stalls?
    !@stall_ratings.index(0)    
  end
  
  def first_empty_stall
    @stalls.index(false) + 1
  end

  def rate_stalls
    ratings = []
    @stalls.each_with_index do |stall, index|
      rating = 0
      rating = 1 if would_be_next_to_a_guy?(index)
      rating = 2 if would_be_next_to_two_guys?(index)
      rating = 3 if stall
      ratings << rating
    end
    return ratings
  end

  def would_be_next_to_a_guy?(index)
    @stalls[index-1] || @stalls[index+1]
  end
  
  def would_be_next_to_two_guys?(index)
    (@stalls[index-2] && @stalls[index-1]) || (@stalls[index+1] && @stalls[index+2])
  end
  
  def best_stall
    @stall_ratings.index(@stall_ratings.min) + 1
  end
end

bathroom_spec.rb

require 'rspec'
require_relative 'bathroom'

describe Bathroom do
  describe "#find_stall" do
    
    describe "Rule #1: Farthest from the door" do      
      describe "when no line" do
        it do
          @bathroom = Bathroom.new(stalls: [false, false, false, false, false], line: false)
          @bathroom.find_stall.should == 1
        end
      end

      describe "when there is a line" do
        it do
          @bathroom = Bathroom.new(stalls: [false, true, true, false, true], line: true)
          @bathroom.find_stall.should == 1
        end
      end
      
      describe "when guys are standing next to each other" do
        it do
          @bathroom = Bathroom.new(stalls: [false, true, true, false, false], line: false)
          @bathroom.find_stall.should == 1
        end
      end
    end
    
    describe "Rule #2: Don't stand next to a dude" do
      describe "when no line" do
        it do
          @bathroom = Bathroom.new(stalls: [false, true, false, false, false], line: false)
          @bathroom.find_stall.should == 4
        end
      end
    
      describe "when there is a line" do
        it do
          @bathroom = Bathroom.new(stalls: [false, true, false, false, false], line: true)
          @bathroom.find_stall.should == 1
        end
      end
      
      describe "when guys are standing next to each other" do
        it do
          @bathroom = Bathroom.new(stalls: [false, true, true, false, true, false], line: false)
          @bathroom.find_stall.should == nil
        end
      end
    end
    
    describe "Rule #3: Really don't stand next to 2 dudes" do      
      describe "when no line" do
        it do
          @bathroom = Bathroom.new(stalls: [true, true, false, false, true], line: false)
          @bathroom.find_stall.should == nil
        end
      end
    
      describe "when there is a line" do
        it do
          @bathroom = Bathroom.new(stalls: [true, true, false, false, true], line: true)
          @bathroom.find_stall.should == 3
        end
      end
      
      describe "when guys are standing next to each other" do
        it do
          @bathroom = Bathroom.new(stalls: [true, true, false, false, true], line: false)
          @bathroom.find_stall.should == nil
        end
      end
    end
  end
end