Measure time spent in DB in a RSpec suite

rails_helper.rb

RSpec.configure do |config|
  config.before(:suite) do
    $_events = []
  end

  config.around do |example|
    callback = lambda do |*args|
      $_events << ActiveSupport::Notifications::Event.new(*args)
    end

    ActiveSupport::Notifications.subscribed(callback, "sql.active_record") do
      example.run
    end
  end

  config.after(:suite) do
    p $_events.sum(&:duration)
  end
end