Speed up tests with the following gist

test_helper.rb

#
# Credit goes to jamis
# http://37signals.com/svn/posts/2742-the-road-to-faster-tests

#
# wipe almost all of the instance variables from the object

teardown :scrub_instance_variables

@@reserved_ivars = %w(@loaded_fixtures @test_passed @fixture_cache @method_name @_assertion_wrapped @_result)

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

#
# reduce the frequency at which the Garbage Collector runs
setup :begin_gc_deferment
teardown :reconsider_gc_deferment

DEFERRED_GC_THRESHOLD = (ENV['DEFER_GC'] || 1.0).to_f

@@last_gc_run = Time.now

def begin_gc_deferment
  GC.disable if DEFERRED_GC_THRESHOLD > 0
end

def reconsider_gc_deferment
  if DEFERRED_GC_THRESHOLD > 0 && Time.now - @@last_gc_run >= DEFERRED_GC_THRESHOLD
    GC.enable
    GC.start
    GC.disable

    @@last_gc_run = Time.now
  end
end