snippet.rb

Factory.define :user_guest, :class => User do |f|
  f.sequence(:username) { |n| "foo#{n}" }
  f.password "foobar"
  f.password_confirmation { |u| u.password }
  f.sequence(:email) { |n| "foo#{n}@example.com" }
  f.role "guest"
  f.comments {|c| c.association(:comment) }
end