some tweaks so it fails gracefully on systems that do not have free command

features/support/env.rb

@@ -104,8 +104,8 @@ end
 # https://makandracards.com/makandra/950-speed-up-rspec-by-deferring-garbage-collection
 require File.join(File.dirname(__FILE__), "..", "..", "spec", "support", "deferred_garbage_collection")
 Before do
-  DeferredGarbageCollection.start unless ENV['TRAVIS']
+  DeferredGarbageCollection.start
 end
 After do
-  DeferredGarbageCollection.reconsider unless ENV['TRAVIS']
+  DeferredGarbageCollection.reconsider 
 end

spec/spec_helper.rb

@@ -105,9 +105,9 @@ end
 # https://makandracards.com/makandra/950-speed-up-rspec-by-deferring-garbage-collection
 RSpec.configure do |config|
   config.before(:all) do
-    DeferredGarbageCollection.start unless ENV['TRAVIS']
+    DeferredGarbageCollection.start
   end
   config.after(:all) do
-    DeferredGarbageCollection.reconsider unless ENV['TRAVIS']
+    DeferredGarbageCollection.reconsider 
   end
 end

spec/support/deferred_garbage_collection.rb

@@ -7,16 +7,27 @@ class DeferredGarbageCollection
   @@last_gc_run = Time.now
 
   def self.start
+    return if unsupported_enviroment
     GC.disable if DEFERRED_GC_THRESHOLD > 0
   end
 
-  def self.reconsider
-    mem = %x(free).split(" ")
-    percent_used = mem[8].to_i / (mem[7].to_i/100)
+  def self.memory_threshold
+    mem = %x(free 2>/dev/null).to_s.split(" ")
+    return nil if mem.empty?
+    mem[8].to_i / (mem[7].to_i/100)
+  end
 
-    puts "percent memory used #{percent_used}" # just for info, as soon as we got some numbers remove it
+  def self.reconsider
+    return if unsupported_enviroment
 
-    if( (DEFERRED_GC_THRESHOLD > 0 && Time.now - @@last_gc_run >= DEFERRED_GC_THRESHOLD) || percent_used > 90 )
+    if (percent_used = self.memory_threshold)
+      running_out_of_memory = percent_used > 90
+      puts "percent memory used #{percent_used}" # just for info, as soon as we got some numbers remove it
+    else
+      running_out_of_memory = false
+    end
+ 
+    if( (DEFERRED_GC_THRESHOLD > 0 && Time.now - @@last_gc_run >= DEFERRED_GC_THRESHOLD) || running_out_of_memory )
       GC.enable
       GC.start
       GC.disable
@@ -24,4 +35,8 @@ class DeferredGarbageCollection
     end
   end
 
+  def self.unsupported_enviroment
+    # ENV['TRAVIS']
+  end
+
 end