Faster RSpec with manual garbage collection

garbage_collection.rb

##
# spec/support/garbage_collection.rb
#
# Inspired by:
# http://www.rubyinside.com/careful-cutting-to-get-faster-rspec-runs-with-rails-5207.html
#
# At time of writing:
# reduces duration from ~16.7sec to ~15.7sec (6% improvement)
# increases peak memory usage from 150mb to 200mb (33% increase)

RSpec.configure do |config|

  config.before(:suite) { GC.disable }
  config.after(:suite) { GC.enable }

  example_counter = 0

  config.after(:each) do
    if example_counter % 32 == 0
      GC.enable
      GC.start
      GC.disable
    end
    example_counter += 1
  end

end