spec.rb

require 'active_support/core_ext/array'

class FactoryGirl
  attr_accessor :options

  def self.create(model, options = {})
    new(model, options)
  end

  def initialize(model, options)
    @model = model
    @options = options
  end
end

class DatabaseCleaner
  def self.clean; end
end

def sign_in(u); end
def sign_out(u); end

def authenticated_as(roles, options = nil, &block)

  Array.wrap(roles).each do |role|
    context "when logged in as a #{role}" do
      before(:each) {
        options = self.instance_eval &options if options.is_a? Proc
        @user = FactoryGirl.create role, *Array.wrap(options)
        sign_in @user
      }
      after(:each)  { sign_out @user }

      instance_eval &block
    end
  end
end

describe "Foo" do
  let(:test_val) { "Test Value" }
  authenticated_as :user, Proc.new{ {value: test_val.upcase} } do
    context "A case to populate params" do
      let(:params) { "original recipe" }
      specify { params.should == "original recipe" }
    end

    context "and a case to reuse them" do
      let(:params) { "extra crispy" }
      specify { params.should == "extra crispy"}
    end
  end
end