faster_specs.rb

# Using Rspec 2.5.0 + Spork
# 
# Before the hack: 
# 2131/2131:   100% |==========================================| Time: 00:02:26
#
# After the hack:
# 2131/2131:   100% |==========================================| Time: 00:02:09

# spec/spec_helper.rb (simplified...)
# Adapted from http://37signals.com/svn/posts/2742-the-road-to-faster-tests
module FasterTests
  def scrub_instance_variables
    reserved_ivars = %w(@loaded_fixtures @test_passed @fixture_cache @method_name @_assertion_wrapped @_result)
    (instance_variables - reserved_ivars).each do |ivar|
      instance_variable_set(ivar, nil)
    end
  end
end

RSpec.configure do |config|
  config.include FasterTests
  config.before(:all) { scrub_instance_variables }
end