[Truffle] Add a script to check methods parity with MRI.

.gitignore

@@ -66,6 +66,7 @@ target
 test/prawn
 test/rails
 test/testapp/testapp
+test/truffle/*.methods
 tool/nailgun/Makefile
 tool/nailgun/config.log
 tool/nailgun/config.status

test/truffle/test_methods_parity.rb

@@ -0,0 +1,33 @@
+=begin
+Run first with JRuby+Truffle, then with MRI:
+
+$ .../jruby -X+T test_methods_parity.rb > truffle.methods
+$ .../ruby test_methods_parity.rb truffle.methods > mri.methods
+Compare with:
+$ git diff -U10 --no-index mri.methods truffle.methods
+  Red is what we don't implement yet,
+  Green is methods not existing in MRI (which should be fixed!)
+=end
+
+start = BasicObject # Numeric
+
+modules = Object.constants.sort.map { |c|
+  Object.const_get(c)
+}.select { |v|
+  Module === v and !v.instance_methods(false).empty?
+}.select { |mod|
+  !mod.name.end_with?("Error")
+}.select { |mod|
+  mod <= start
+}
+
+if RUBY_ENGINE == "ruby" and truffle_file = ARGV.first
+  truffle_modules = File.readlines(truffle_file).map(&:chomp).grep(/^[A-Z]/)
+  modules = modules.select { |mod| truffle_modules.include? mod.name }
+end
+
+modules.each do |mod|
+  puts
+  puts mod.name
+  puts mod.instance_methods(false).sort
+end