performance.rb

require 'benchmark/ips'
require 'benchmark/memory'

# For use within a spec. Three methods must be provided within the current
# namespace. #performance_object, #performance_a, and #performance_b. 
# The object is the object with the methods to be measured.
# The performance a and b are the methods to be compared.
# The original is #performance_a.
#
# Example use
#
# let(:performance_object) { parasite_property }
# let(:performance_a)      { :compare_restore_room_rates }
# let(:performance_b)      { :restore_room_rates }
#
# it_behaves_like 'Performance'

class Performance
  A = 'original'.freeze
  B = 'new'.freeze

  def initialize(object, a, b)
    @object = object
    @a      = a
    @b      = b
  end

  def ips
    Benchmark.ips do |x|
      x.config time: 2, warmup: 5
      x.report(A) { @object.send @a }
      x.report(B) { @object.send @b }
      x.compare!
    end
  end

  def memory
    Benchmark.memory do |x|
      x.report(A) { @object.send @a }
      x.report(B) { @object.send @b }
    end
  end
end

shared_examples_for 'Performance' do
  let(:performance) { Performance.new performance_object, performance_a, performance_b }

  it 'Iterations per second' do
    performance.ips
  end

  it 'Memory and object consumption' do
    performance.memory
  end
end