properly pass options when fields_for is called with colletion

Closes ryanb#214

lib/nested_form/builder_mixin.rb

@@ -75,10 +75,11 @@ def fields_for_with_nested_attributes(association_name, *args)
       # TODO Test this better
       block = args.pop || Proc.new { |fields| @template.render(:partial => "#{association_name.to_s.singularize}_fields", :locals => {:f => fields}) }
 
-      options = if args[0].kind_of? Array # Rails 3.0.x
-        args[0].dup.extract_options!
-      else
-        args.dup.extract_options!
+      options = args.dup.extract_options!
+
+      # Rails 3.0.x
+      if options.empty? && args[0].kind_of?(Array)
+        options = args[0].dup.extract_options!
       end
 
       @fields ||= {}

spec/nested_form/builder_spec.rb

@@ -126,6 +126,18 @@
 
         output.should match(/div.+data-blueprint="Task"/)
       end
+
+      it "doesn't render wrapper div when collection is passed" do
+        task = project.tasks.build
+        fields = subject.fields_for(:tasks, project.tasks, :wrapper => false) { 'Task' }
+
+        fields.should eq('Task')
+
+        subject.link_to_add 'Add', :tasks
+        output = template.send(:after_nested_form_callbacks)
+
+        output.should match(/div.+data-blueprint="Task"/)
+      end
     end
 
     context "with options" do