test.local.rb

#base on http://ariejan.net/2011/09/24/rspec-speed-up-by-tweaking-ruby-garbage-collection
class DeferredGarbageCollection

  MEM_FREE_FOR_GC_THRESHOLD = (ENV['MEM_FREE_FOR_GC_THRESHOLD'] || 500).to_f

  @@last_gc_run = Time.now

  def self.start
    GC.disable if MEM_FREE_FOR_GC_THRESHOLD > 0
  end

  def self.reconsider
    memory = Vmstat.snapshot.memory

    #get amount of memory free in MB's
    mem_free = memory.free * memory.pagesize / 1024 / 1024

    if MEM_FREE_FOR_GC_THRESHOLD > mem_free
      GC.enable
      GC.start
      GC.disable
      @@last_gc_run = Time.now
    end
  end
end


RSpec.configure do |config|
  config.before(:suite) do
    DeferredGarbageCollection.start
  end

  config.after(:all) do
    DeferredGarbageCollection.reconsider
  end
end