diff --git a/lib/fb_graph2/attribute_assigner.rb b/lib/fb_graph2/attribute_assigner.rb
index 862ab96..3d44cc5 100644
--- a/lib/fb_graph2/attribute_assigner.rb
+++ b/lib/fb_graph2/attribute_assigner.rb
@@ -17,7 +17,7 @@ module FbGraph2
 
     def assign(attributes)
       self.raw_attributes = attributes
-      self.class.registered_attributes.each do |type, keys|
+      Array(self.class.registered_attributes).each do |type, keys|
         keys.each do |key|
           raw = attributes[key]
           if raw.present?
diff --git a/spec/fb_graph2/node_subclass_spec.rb b/spec/fb_graph2/node_subclass_spec.rb
new file mode 100644
index 0000000..15d651d
--- /dev/null
+++ b/spec/fb_graph2/node_subclass_spec.rb
@@ -0,0 +1,23 @@
+require 'spec_helper'
+
+module FbGraph2
+  class NodeSubClass < Node
+  end
+end
+
+describe FbGraph2::NodeSubClass do
+  let(:klass) { FbGraph2::NodeSubClass }
+  let(:instance) { klass.new 'identifier' }
+
+  context 'class' do
+    subject { klass }
+    it { should respond_to :register_attributes }
+    it { should respond_to :registered_attributes }
+    it { should respond_to :registered_attributes= }
+  end
+
+  context 'instance' do
+    subject { instance }
+    it { should respond_to :assign }
+  end
+end
\ No newline at end of file
diff --git a/spec/fb_graph2/page_spec.rb b/spec/fb_graph2/page_spec.rb
new file mode 100644
index 0000000..6a50e87
--- /dev/null
+++ b/spec/fb_graph2/page_spec.rb
@@ -0,0 +1,5 @@
+require 'spec_helper'
+
+describe FbGraph2::Page do
+  it :TODO
+end
\ No newline at end of file
diff --git a/spec/fb_graph2/user_spec.rb b/spec/fb_graph2/user_spec.rb
index a038805..d1965ba 100644
--- a/spec/fb_graph2/user_spec.rb
+++ b/spec/fb_graph2/user_spec.rb
@@ -1,8 +1,5 @@
 require 'spec_helper'
 
 describe FbGraph2::User do
-  it do
-    p FbGraph2::User, FbGraph2::User.registered_attributes
-    p FbGraph2::Page, FbGraph2::Page.registered_attributes
-  end
+  it :TODO
 end
\ No newline at end of file