slightly better messages for unsupported ruby

Very slightly unfortunately, just just enought to find the error.
Also testing what is unsupported, so it's documented.

test/ruby/test_basic_values.rb

@@ -33,8 +33,8 @@ module Ruby
       assert_equal SymbolConstant , lst.class , lst.inspect
     end
     def test_dstr
-      assert_raises RuntimeError do
-        compile( '"dstr#{self}"')
+      assert_raises Ruby::ProcessError do
+        compile( '"interpolate #{self}"')
       end
     end
 

test/ruby/test_not_implemented.rb

@@ -0,0 +1,20 @@
+require_relative "helper"
+
+module Ruby
+  class NotImplemented < Minitest::Test
+    include RubyTests
+
+    def assert_handler_missing(input)
+      assert_raises(Ruby::ProcessError){ compile(input) }
+    end
+
+    def test_module
+      assert_handler_missing "module Name ; end"
+    end
+
+    def test_module_module_scoped
+      assert_handler_missing( "M::Module" )
+    end
+
+  end
+end

test/ruby/test_variables.rb

@@ -51,9 +51,6 @@ module Ruby
       assert_equal ModuleName , lst.class
       assert_equal :Module , lst.name
     end
-    def test_module_module_scoped
-      assert_raises {compile( "M::Module" ) }
-    end
   end
   class TestVariablesVool < MiniTest::Test
     include RubyTests