factory.rb

# I wanted a simple object factory for use with Ohm, I'm used to factory_girl
# and fabrication. After a few minutes of messing around and trying to get them
# to work with Ohm, I decided to try giving it a whirl myself...

class Factory
  def self.factories
    @factories ||= {}
  end

  def self.define(model, &block)
    factories[model] = begin
      factory = new
      factory.instance_eval(&block)
      factory
    end
  end

  def self.build(model, overloads = {})
    factory = factories[model]
    raise ArgumentError, "There is no factory for #{model} yet." unless factory
    model.new(factory.defaults.merge(overloads))
  end

  def self.create(model, overloads = {})
    instance = build(model, overloads)
    instance.save
    instance
  end

  attr_reader :defaults

  def initialize
    @defaults = {}
  end

  def method_missing(name, value)
    defaults[name] = value
  end
end

def Factory(*args)
  Factory.create(*args)
end

# Usage:
#
# class Tree < Ohm::Model
#   attribute :name
#   attribute :height
# end
#
# Factory.define(Tree) do
#   name   'Pine'
#   height '22 feet'
# end
#
# @tree = Factory(Tree, :name => 'Maple')
#
# Anyways, obvs this implementation is limited but can be easily extended. I
# just thought you might find it interesting.
#
# Carsten