start a new ruby layer to do the to_vool conversion

the "normalization" is getting more and more complicated and is not tested
And it seems i really don't like working with the untyped ast

test/ruby/test_op_assignment.rb

@@ -0,0 +1,41 @@
+require_relative "helper"
+
+module Ruby
+  module OpAss
+    def test_local_name
+      assert_equal :foo , @lst.name
+    end
+    def test_local_value
+      assert_equal SendStatement , @lst.value.class
+    end
+    def test_local_method
+      assert_equal :+ , @lst.value.name
+    end
+    def test_local_receiver
+      assert_equal :foo , @lst.value.receiver.name
+    end
+    def test_local_receiver
+      assert_equal 5 , @lst.value.arguments.first.value
+    end
+  end
+  class TestLocalOpAssignX < MiniTest::Test
+    include OpAss
+    include RubyTests
+    def setup
+      @lst = compile( "foo += 5")
+    end
+    def test_local_ass
+      assert_equal LocalAssignment , @lst.class
+    end
+  end
+  class TestIvarOpAssignX < MiniTest::Test
+    include OpAss
+    include RubyTests
+    def setup
+      @lst = compile( "@foo += 5")
+    end
+    def test_ivar_ass
+      assert_equal IvarAssignment , @lst.class
+    end
+  end
+end