Example of Ruby's behavior when modifying properties/values of objects/hashes passed as parameters

gistfile1.rb

This test passes:

 it "should tell me how params are passed" do
    # that new car smell
    car = Car.new
    car.colour = "blue"
    # this car smells like hash
    car_hash = {'colour' => 'blue'}
    
    # both cars were created blue yeah?
    car.colour.should eq('blue')
    car_hash['colour'].should eq('blue')
    
    # now we paint them red
    make_it_red(car)
    set_value_to_red(car_hash)
    
    # they're read right?
    car.colour.should eq('red')
    car_hash['colour'].should eq('red')
    # not still blue? Not even a little bit?
    car.colour.should_not eq('blue')
    car_hash['colour'].should_not eq('blue')
    
  end
  
  def make_it_red(car)
    car.colour = 'red'
  end
  
  def set_value_to_red(hash)
    hash['colour'] = 'red'
  end
  
  class Car
    attr_accessor :colour
  end