* Rename NullAdapter to SimpleAdapter

* Introduce abstract Adapter class
* Organaze test structure to match convemtions

lib/action_controller/serialization.rb

@@ -12,7 +12,7 @@ module ActionController
       if serializer
         # omg hax
         object = serializer.new(resource)
-        adapter = ActiveModel::Serializer::Adapter::NullAdapter.new(object)
+        adapter = ActiveModel::Serializer::Adapter::SimpleAdapter.new(object)
 
         super(adapter, options)
       else

lib/active_model/serializer.rb

@@ -3,6 +3,7 @@ module ActiveModel
     extend ActiveSupport::Autoload
     autoload :Configuration
     autoload :ArraySerializer
+    autoload :Adapter
     include Configuration
 
     class << self

lib/active_model/serializer/adapter.rb

@@ -0,0 +1,20 @@
+module ActiveModel
+  class Serializer
+    class Adapter
+      extend ActiveSupport::Autoload
+      autoload :SimpleAdapter
+
+      def initialize(serializer)
+        @attributes = serializer.attributes
+      end
+
+      def serializable_hash(options = {})
+        raise NotImplementedError, 'This is abstract method. Should be implemented at concrete adapter.'
+      end
+
+      def to_json(options = {})
+        raise NotImplementedError, 'This is abstract method. Should be implemented at concrete adapter.'
+      end
+    end
+  end
+end

lib/active_model/serializer/adapter/simple_adapter.rb

@@ -1,11 +1,7 @@
 module ActiveModel
   class Serializer
     class Adapter
-      class NullAdapter
-        def initialize(adapter)
-          @attributes = adapter.attributes 
-        end
-
+      class SimpleAdapter < Adapter
         def to_json(options={})
           @attributes.each_with_object({}) do |(attr, value), h|
             h[attr] = value

lib/active_model_serializers.rb

@@ -1,7 +1,7 @@
 require "active_model"
 require "active_model/serializer/version"
 require "active_model/serializer"
-require "active_model/serializer/adapter/null_adapter"
+require "active_model/serializer/adapter/simple_adapter"
 
 begin
   require 'action_controller'

test/adapter/simple_adapter_test.rb

@@ -3,15 +3,15 @@ require 'test_helper'
 module ActiveModel
   class Serializer
     class Adapter
-      class NullAdapterTest < Minitest::Test
+      class SimpleAdapterTest < Minitest::Test
         def setup
           @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
           @profile_serializer = ProfileSerializer.new(@profile)
 
-          @adapter = NullAdapter.new(@profile_serializer)
+          @adapter = SimpleAdapter.new(@profile_serializer)
         end
 
-        def test_null_adapter
+        def test_simple_adapter
           assert_equal('{"name":"Name 1","description":"Description 1"}',
                        @adapter.to_json)
 

test/adapter_test.rb

@@ -0,0 +1,25 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class AdapterTest < Minitest::Test
+      def setup
+        profile = Profile.new
+        serializer = ProfileSerializer.new(profile)
+        @adapter = ActiveModel::Serializer::Adapter.new(serializer)
+      end
+
+      def test_serializable_hash_is_abstract_method
+        assert_raises(NotImplementedError) do
+          @adapter.serializable_hash(only: [:name])
+        end
+      end
+
+      def test_serializable_hash_is_abstract_method
+        assert_raises(NotImplementedError) do
+          @adapter.to_json(only: [:name])
+        end
+      end
+    end
+  end
+end