Economics challenge for (RPCFN: Economics 101 (#13)) - Oto Brglez

economics.rb

require 'nokogiri'

class World
  attr_reader :continents
  
  def initialize(world_xml="cia-1996.xml")
    @continents = []
    
    if File.exists?(world_xml)
      @noko = Nokogiri::XML(File.open world_xml )
      @continents = @noko.xpath("/cia/continent").map do |n| 
        c = Continent.new :id => n['id'], :name => n['name']
        @noko.xpath("/cia/country[@continent='#{c.to_s}']").each do |country|
          c.countries.push Country.new :name => country['name'], :population => country['population'], :inflation => country['inflation']
        end
        c.countries.sort!{ |a,b| a.name.downcase <=> b.name.downcase }
        c
      end
      @continents.sort!{ |a,b| a.name.downcase <=> b.name.downcase }
    end
    
  end
  
  def country_with_biggest_population
    continents.collect{ |c| c.countries }.flatten.max{ |a,b| a.population.to_i <=> b.population.to_i  }
  end
  
  def countries_with_highest_inflation_rates
    continents.collect{ |c| c.countries }.flatten.sort { |a,b| b.inflation.to_f <=> a.inflation.to_f }.slice(0,5)
  end
  
end

class Continent
  attr_reader :countries, :id, :name
  
  def initialize(params=nil)
    @countries = []
    @id = params[:id] if params[:id]
    @name = params[:name] if params[:name]
  end
  
  def to_s
    "#{@name}"
  end
  
end

class Country
  attr_reader :name, :population, :inflation
  
  def initialize(params=nil)
    @name = params[:name] if params[:name]
    @population = params[:population].to_i if params[:population]
    @inflation = params[:inflation].to_f if params[:inflation]
  end
  
  def to_s
    "#{@name}"
  end

end

economics_test.rb

#!/usr/bin/env ruby -w

require 'test/unit'
require './economics'

class EconomicsTest < Test::Unit::TestCase
  
  def setup
    @world = World.new
  end
  
  def test_world
    assert_equal @world.continents.count.to_s, "6"
  end
  
  def test_number_of_countries_of_first_continent
    assert_not_equal @world.continents.first.countries.count, "0"
  end
  
  def test_continents_order
    assert_equal @world.continents.first.name.downcase , "africa"
  end
  
  def test_is_china_the_biggest
    assert_equal @world.country_with_biggest_population.name , "China"
  end
  
  def test_countries_with_highest_inflation_rates
    assert_equal %w(Belarus Turkey Azerbaijan Malawi Yemen), @world.countries_with_highest_inflation_rates.map(&:name)
  end
  
  def test_task_one
    puts "
    1) What is the population of the country with the most people?
    Yes, we know it\'s China, but just how many people lived there in 1996?"
  
    puts "
    Answer: People in china : #{ @world.country_with_biggest_population.population }"
  
  end
  
  def test_task_two
    puts "
    2) What are the five countries with the highest inflation rates, and what were those rates in 1996?"
    
    puts "
    Answer: Five countries with the highest inflation rates are:"
    
    @world.countries_with_highest_inflation_rates.each do |country|
      puts "\t#{country} - #{country.inflation}"
    end
    
  end
  
  def test_task_three
    puts"
    3) What are the six continents in the file and which countries belong to which continent?
    Can you also produce them in alphabetical order?"
    
    @world.continents.each do |continent|
      puts "\n\t #{continent}: \n" + continent.countries.map(&:name).join(", ")
    end
  end
  
end