FIX: Allow event to return nil without failure

lib/sinatra.rb

@@ -357,7 +357,8 @@ module Sinatra
           [:complete, context.instance_eval(&result.block)]
         end
         body = returned.to_result(context)
-        context.body = String === body ? [*body] : body
+        body = '' unless body.respond_to?(:each)
+        context.body = body.kind_of?(String) ? [*body] : body
         context.finish
       rescue => e
         raise e if options.raise_errors

test/app_test.rb

@@ -6,6 +6,16 @@ context "Sinatra" do
     Sinatra.application = nil
   end
   
+  specify "should handle result of nil" do
+    get '/' do
+      nil
+    end
+    
+    get_it '/'
+    should.be.ok
+    body.should == ''
+  end
+  
   specify "handles events" do
     get '/:name' do
       'Hello ' + params[:name]