Growing a Test Suite Screencast Review

This is the review of the solution discussed in Growing a Test Suite Screencast.

Here is a list of things that the solution violates:

1. Separate Command from Query.
     digest method is a command. digest method should not return any value
2. Allocate responsibilities to the right class.
    digest method does not belong to the Cheese class.

3. Law of Demeter.

Here is my solution:

class Walrus
  attr_reader :energy
 
  def initialize
    @energy = 0
  end
 
  def eat(food)
    digest
    @energy += food.energy
  end
 
  private
 
  def digest
    p 'Digesting...'
  end
end

class Cheese
  def energy
    100
  end
end


cheese = Cheese.new
w  = Walrus.new

p "Energy before eating is : #{w.energy}"

w.eat(cheese)

p "Energy now is : #{w.energy}"