add valgrind rake task to ensure nothing leaks

Rakefile

@@ -13,3 +13,42 @@ task :default => :test
 gem = Gem::Specification.load( File.dirname(__FILE__) + '/mini_racer.gemspec' )
 Rake::ExtensionTask.new( 'mini_racer_extension', gem )
 
+
+# via http://blog.flavorjon.es/2009/06/easily-valgrind-gdb-your-ruby-c.html
+namespace :test do
+  # partial-loads-ok and undef-value-errors necessary to ignore
+  # spurious (and eminently ignorable) warnings from the ruby
+  # interpreter
+  VALGRIND_BASIC_OPTS = "--num-callers=50 --error-limit=no \
+                         --partial-loads-ok=yes --undef-value-errors=no"
+
+  desc "run test suite under valgrind with basic ruby options"
+  task :valgrind => :compile do
+    cmdline = "valgrind #{VALGRIND_BASIC_OPTS} ruby test/test_leak.rb"
+    puts cmdline
+    system cmdline
+  end
+
+  desc "run test suite under valgrind with leak-check=full"
+  task :valgrind_leak_check => :compile do
+    cmdline = "valgrind #{VALGRIND_BASIC_OPTS} --leak-check=full ruby test/test_leak.rb"
+    puts cmdline
+    require 'open3'
+    _, stderr = Open3.capture3(cmdline)
+
+    section = ""
+    stderr.split("\n").each do |line|
+
+      if line =~ /==.*==\s*$/
+        if (section =~ /mini_racer|SUMMARY/)
+          puts
+          puts section
+          puts
+        end
+        section = ""
+      else
+        section << line << "\n"
+      end
+    end
+  end
+end

test/test_leak.rb

@@ -0,0 +1,43 @@
+$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
+require 'mini_racer'
+require 'objspace'
+
+def has_contexts
+  ObjectSpace.each_object(MiniRacer::Context).count > 0
+end
+
+def clear
+  while has_contexts
+    GC.start
+  end
+end
+
+def test
+  context = MiniRacer::Context.new
+  context.attach("add", proc{|a,b| a+b})
+  context.eval('1+1')
+  context.eval('"1"')
+  context.eval('a=function(){}')
+  context.eval('a={a: 1}')
+  context.eval('a=[1,2,"3"]')
+  context.eval('add(1,2)')
+end
+
+
+def start
+  n = 100
+
+  puts "Running #{n} contexts"
+
+  n.times do
+    test
+    clear
+  end
+
+  puts "Ensuring garbage is collected"
+
+
+  puts "Done"
+end
+
+start