speeding up rspec by deferring garbage collection

-> https://makandracards.com/makandra/950-speed-up-rspec-by-deferring-garbage-collection

on my machine the rspec tests went from taking 5min 02sec to 3min 29sec :O
(31% improvement)

spec/spec_helper.rb

@@ -101,3 +101,13 @@ Spork.each_run do
   AppConfig.load!
   AppConfig.setup!
 end
+
+# https://makandracards.com/makandra/950-speed-up-rspec-by-deferring-garbage-collection
+RSpec.configure do |config|
+  config.before(:all) do
+    DeferredGarbageCollection.start
+  end
+  config.after(:all) do
+    DeferredGarbageCollection.reconsider
+  end
+end

spec/support/deferred_garbage_collection.rb

@@ -0,0 +1,22 @@
+
+# https://makandracards.com/makandra/950-speed-up-rspec-by-deferring-garbage-collection
+class DeferredGarbageCollection
+
+  DEFERRED_GC_THRESHOLD = (ENV['DEFER_GC'] || 10.0).to_f
+
+  @@last_gc_run = Time.now
+
+  def self.start
+    GC.disable if DEFERRED_GC_THRESHOLD > 0
+  end
+
+  def self.reconsider
+    if DEFERRED_GC_THRESHOLD > 0 && Time.now - @@last_gc_run >= DEFERRED_GC_THRESHOLD
+      GC.enable
+      GC.start
+      GC.disable
+      @@last_gc_run = Time.now
+    end
+  end
+
+end