WARNING: concept-quality code, that is, anything may change!

Other than that, this is an attempt to make code like below work:

require 'spec/rails/ar'

describe BarController do
  context "having some items" do
    before do
      Drink.csv_send "
              , volume(i) , price(f)
        Juice , 250       , 2.50
        Beer  , 473       , 5.50
        "    
      Food.Bun :weight => 20, :price => 2
    end

    it "should update the prices upon request" do
      post :price_change :category => 'food', :by => '+10%'
      response.should be_success

      Drink.constinsts.each_value { |d| d.should be_the_same }
      Food.Bun.should be_the_same_but :price => 2.20
    end

    after do
      # TODO resetting the database?
    end
end

• which roughly does in already.

Note that you will need xgem from http://github.com/costa/xgem and export RUBYLIB="<a path to its ./lib>:$RUBYLIB" until the gem is developed, packaged and distributed.