spud.rb

# Pattern: Replace exception with test

class PreRefactoringRoster
  def initialize
    @members = []
  end
  
  attr_reader :members
  
  def add_user(name)
    begin
      add_user_to_game(name)
    rescue Exception => e
      add_user_to_game(name + rand(10000).to_s)
    end
    @members.last
  end

  private
  def add_user_to_game(this_name)
    # totally contrived
    if @members.find{|n| n.name.eql?(this_name)}
      raise "A player already has this username"
    else
      @members << Person.new(this_name)
    end
  end
end

class PostRefactoringRoster
  def initialize
    @members = []
  end
  
  attr_reader :members
  
  def add_user(name)
    if @members.find{|n| n.name.eql?(name)}
      add_user_to_game(name + rand(10000).to_s)
    else
      add_user_to_game(name)
    end
    @members.last
  end

  private
  def add_user_to_game(this_name)
    # totally contrived
    if @members.find{|n| n.name.eql?(this_name)}
      raise "A player already has this username"
    else
      @members << Person.new(this_name)
    end
  end
end

class Person
  def initialize(name)
    @name = name
  end
  attr_reader :name
end

spud_spec.rb

require "spud"

describe "pre refactoring" do
  before(:each) do
    @roster = PreRefactoringRoster.new
  end
  
  it "should add a random number to the username if you try to add it 2x" do
    @roster.add_user("Carol")
    @roster.add_user("Carol").name.should match(/Carol\d+/)
  end

end

describe "post refactoring" do
  before(:each) do
    @roster = PostRefactoringRoster.new
  end
  
  it "should add a random number to the username if you try to add it 2x" do
    @roster.add_user("Carol")
    @roster.add_user("Carol").name.should match(/Carol\d+/)
  end

end