Rspec optmization techniques borrowed from 37Signals

rspec_optimize.rb

# method for clearing out instance variables from code blocks
# usage:

Spec::Runner.configure do |config|
 .....

  config.after(:each) do
    scrub_instance_variables
  end
end

.......

@@reserved_ivars = %w(@selected @_backtrace @_proxy @data_tem @_implementation @request @loaded_fixtures @controller @method_name @fixture_cache @_result @deliveries @response @test_passed @_assertion_wrapped)

# instance_variables is an actual method in the rspec source code

  def scrub_instance_variables
    (instance_variables - @@reserved_ivars).each do |ivar|
      instance_variable_set(ivar, nil)
    end
  end