Introduce respond_to? on DecoratedEnumerableProxy

lib/draper/decorated_enumerable_proxy.rb

@@ -20,8 +20,12 @@ module Draper
       @wrapped_collection.send(meth, *args, &block)
     end
 
+    def respond_to?(meth)
+      super || @wrapped_collection.respond_to?(meth)
+    end
+
     def to_s
       "#<DecoratedEnumerableProxy of #{@klass} for #{@wrapped_collection.inspect}>"
     end
   end
-end
+end

spec/base_spec.rb

@@ -188,6 +188,7 @@ describe Draper::Base do
     module Paginator; def page_number; "magic_value"; end; end
     Array.send(:include, Paginator)
     let(:paged_array) { [Product.new, Product.new] }
+    let(:empty_collection) { [] }
     subject { ProductDecorator.decorate(paged_array) }
 
     it "should proxy all calls to decorated collection" do
@@ -201,6 +202,19 @@ describe Draper::Base do
       subject.respond_to?(:to_ary).should be true
       subject.to_a.first.should == ProductDecorator.decorate(paged_array.first)
     end
+
+    it "should delegate respond_to? to the wrapped collection" do
+      decorator = ProductDecorator.decorate(paged_array)
+      paged_array.should_receive(:respond_to?).with(:whatever)
+      decorator.respond_to?(:whatever)
+    end
+
+    it "should return blank for a decorated empty collection" do
+      # This tests that respond_to? is defined for the DecoratedEnumerableProxy
+      # since activesupport calls respond_to?(:empty) in #blank
+      decorator = ProductDecorator.decorate(empty_collection)
+      decorator.should be_blank
+    end
   end
 
   describe "a sample usage with denies" do