diff --git a/lib/parfait/binary_code.rb b/lib/parfait/binary_code.rb
index c2a7ed3a..31f7a61c 100644
--- a/lib/parfait/binary_code.rb
+++ b/lib/parfait/binary_code.rb
@@ -1,18 +1,18 @@
-# A typed method object is a description of the method, it's name etc
-#
-# But the code that the method represents, the binary, is held as an array
-# in one of these.
-#
-
 module Parfait
 
+  # A typed method object is a description of the method, it's name etc
+  #
+  # But the code that the method represents, the binary, is held as an array
+  # in these. As Objects are fixed size (this one 16 words), we use  linked list
+  # and as the last code of each link is a jump to the next link.
+  #
   class BinaryCode < Data16
-    attr_accessor :next
+    attr_reader :next
 
     def initialize(total_size)
       super()
       if total_size > self.data_length
-        @next = BinaryCode.new(total_size - data_length)
+        @next = BinaryCode.new(total_size - data_length - 1) #one for the jump
       end
       #puts "Init with #{total_size} for #{object_id}"
     end
@@ -22,18 +22,18 @@ module Parfait
     def data_length
       14
     end
-    def char_length
+    def byte_length
       4*data_length
     end
-    def set_char(c , index)
-      if index >= char_length
+    def set_char(index , char)
+      if index >= byte_length
         puts "Pass it on #{index} for #{object_id}"
-        return @next.set_char( c , index - char_length)
+        return @next.set_char( char , index - byte_length)
       end
       word_index = (index - 1) / 4 + 2
       old = get_internal_word( word_index )
-      old = old && c << ((index-1)%4)
-      set_internal_word(word_index , c)
+      old = old && char << ((index-1)%4)
+      set_internal_word(word_index , char)
     end
     def total_byte_length(start = 0 )
       start += 4*14
diff --git a/test/parfait/test_binary_code.rb b/test/parfait/test_binary_code.rb
new file mode 100644
index 00000000..23bbd7bb
--- /dev/null
+++ b/test/parfait/test_binary_code.rb
@@ -0,0 +1,51 @@
+require_relative "../helper"
+
+module Parfait
+  class TestBinaryCode < MiniTest::Test
+
+    def setup
+      Risc.machine.boot
+      @code = BinaryCode.new(10)
+    end
+
+    def test_class
+      assert_equal :BinaryCode, @code.get_type.object_class.name
+    end
+    def test_var_names
+      assert_equal List , @code.get_instance_variables.class
+    end
+    def test_var_names_length
+      assert_equal 2 , @code.get_instance_variables.get_length
+    end
+    def test_var_next
+      assert_equal :next , @code.get_instance_variables[2]
+    end
+    def test_next_nil
+      assert_nil @code.next
+    end
+    def test_data_length
+      assert_equal 14 , @code.data_length
+    end
+    def test_byte_length
+      assert_equal 14*4 , @code.byte_length
+    end
+    def test_next_not_nil
+      @code = BinaryCode.new(16)
+      assert @code.next
+      assert_nil @code.next.next
+    end
+    def test_set_char1
+      assert @code.set_char(1 , 1)
+    end
+    def test_set_char55
+      assert @code.set_char(55 , 1)
+    end
+    def test_set_char56_raises
+      assert_raises {@code.set_char(56 , 1)}
+    end
+    def test_set_char56_double
+      @code = BinaryCode.new(16)
+      assert @code.set_char(56 , 1)
+    end
+  end
+end
diff --git a/test/parfait/test_named_list.rb b/test/parfait/test_named_list.rb
index 41cd183f..68f9b62b 100644
--- a/test/parfait/test_named_list.rb
+++ b/test/parfait/test_named_list.rb
@@ -1,27 +1,32 @@
 require_relative "../helper"
 
-class TestNamedLists < MiniTest::Test
+module Parfait
+  class TestNamedLists < MiniTest::Test
 
-  def setup
-    Risc.machine.boot
-    @space = Parfait.object_space
-    @named_list = @space.first_message.frame
-    @type = @named_list.get_type
-  end
+    def setup
+      Risc.machine.boot
+      @space = Parfait.object_space
+      @named_list = @space.first_message.frame
+      @type = @named_list.get_type
+    end
 
-  def test_named_list_get_type
-    assert_equal Parfait::Type , @type.class
-    assert @type.names
-    assert @named_list.get_instance_variables
-  end
+    def test_named_list_get_type
+      assert_equal Type , @type.class
+      assert @type.names
+      assert @named_list.get_instance_variables
+    end
 
-  def test_new
-    list = Parfait::NamedList.new
-    assert list.get_type
-  end
-
-  def test_var_names
-    list = Parfait::NamedList.new
-    assert list.get_instance_variables
+    def test_new
+      list = NamedList.new
+      assert list.get_type
+    end
+    def test_var_names
+      list = NamedList.new
+      assert_equal List , list.get_instance_variables.class
+    end
+    def test_var_names_length
+      list = NamedList.new
+      assert_equal 1 , list.get_instance_variables.get_length
+    end
   end
 end