Extract multi-sample benchmarking into a helper method

spec/performance/shop_controller_spec.rb

@@ -28,20 +28,10 @@ describe ShopController, type: :controller, performance: true do
     end
 
     it "returns products via json" do
-      results = []
-      4.times do |i|
-        ActiveRecord::Base.connection.query_cache.clear
-        Rails.cache.clear
-        result = Benchmark.measure do
-          xhr :get, :products
-          response.should be_success
-        end
-
-        results << result.total if i > 0
-        puts result
+      results = multi_benchmark(3) do
+        xhr :get, :products
+        response.should be_success
       end
-
-      puts (results.sum / results.count * 1000).round 0
     end
   end
 end

spec/spec_helper.rb

@@ -109,6 +109,7 @@ RSpec.configure do |config|
   config.include OpenFoodNetwork::HtmlHelper
   config.include ActionView::Helpers::DateHelper
   config.include OpenFoodNetwork::DelayedJobHelper
+  config.include OpenFoodNetwork::PerformanceHelper
 
   # FactoryGirl
   require 'factory_girl_rails'

spec/support/performance_helper.rb

@@ -0,0 +1,20 @@
+module OpenFoodNetwork
+  module PerformanceHelper
+    def multi_benchmark(num_samples)
+      results = (0..num_samples).map do |i|
+        ActiveRecord::Base.connection.query_cache.clear
+        Rails.cache.clear
+
+        result = Benchmark.measure { yield }
+
+        puts result
+
+        result.total
+      end.drop(1) # Do not return the first sample
+
+      puts (results.sum / results.count * 1000).round 0
+
+      results
+    end
+  end
+end