tracked_let.rb

# transaction/truncation strategies won't work when you have a
# capybara feature and you must preserve what's already in the
# database
#
# Usage: 
# include TrackedLet
#
# track(:foo) { User.create }
# track!(:foo) { User.create }
# specify { expect(track(User.create)).to be_persisted }

module TrackedLet
  module TrackHelper
    def track(key, &block)
      let(key) do
        instance_eval(&block).tap { |x| __test_records << x }
      end
    end

    def track!(key, &block)
      let!(key) do
        instance_eval(&block).tap { |x| __test_records << x }
      end
    end
  end
  
  def track(value)
    __test_records << value
    value
  end

  def self.included(mod)
    mod.extend TrackHelper
    mod.instance_eval do
      let(:__test_records) { Array.new }
      after { __test_records.each(&:destroy) }
    end
  end
end

Reasons for needing:

• we don't want to wipe the staging data that our customer may be toying with when we run tests
• capybara doesn't have access to what's in a transaction