Fix wrong UninferrableDecoratorError error raising

lib/draper/decoratable.rb

@@ -74,10 +74,10 @@ module Draper
         decorator_name = "#{prefix}Decorator"
         decorator_name.constantize
       rescue NameError => error
+        raise unless error.missing_name?(decorator_name)
         if superclass.respond_to?(:decorator_class)
           superclass.decorator_class
         else
-          raise unless error.missing_name?(decorator_name)
           raise Draper::UninferrableDecoratorError.new(self)
         end
       end

spec/draper/decoratable_spec.rb

@@ -182,6 +182,15 @@ module Draper
         end
       end
 
+      context "when the decorator contains name error" do
+        it "throws an NameError" do
+          # We imitate ActiveSupport::Autoload behavior here in order to cause lazy NameError exception raising
+          allow_any_instance_of(Module).to receive(:const_missing) { Class.new { any_nonexisting_method_name } }
+
+          expect{Model.decorator_class}.to raise_error { |error| expect(error).to be_an_instance_of(NameError) }
+        end
+      end
+
       context "when the decorator can't be inferred" do
         it "throws an UninferrableDecoratorError" do
           expect{Model.decorator_class}.to raise_error UninferrableDecoratorError