Using lambda functions to test exception raising with RSpec.

work_place_spec.rb

require 'spec_helper'

describe WorkPlace do

  # This is the simplest (best) way to test a dependent: :destroy option
  it "has one address and ensures it's destroyed when destroyed itself" do
    should have_one(:address).dependent(:destroy)
  end

  # ... however the use this example does of lambda {} to encapsulate the code
  # which is expected to raise an exception (and prevent the exception to make the example fail)
  # is, IMHO, quite interesting.
  it "ensures it's address is destroyed when destroyed" do
    address = FactoryGirl.create(:address)
    work_place = FactoryGirl.create(:work_place, address: address)

    work_place.destroy

    lambda { Address.find(address.id) }.should raise_error ActiveRecord::RecordNotFound
  end
end

# Credit: http://stackoverflow.com/questions/4946635/rspec-not-working-or-raise-not-raising