Sets Content-Length to body string bytesize

Sets the Conten-Length to the bytesize of the joined body to cover UTF-8

lib/zero/response.rb

@@ -42,7 +42,7 @@ module Zero
     # Also creates one, if it does not exists
     #
     def content_length
-      header['Content-Length'] = body.join.length
+      header['Content-Length'] = body.join.bytesize
     end
 
   end

spec/unit/response/response_spec.rb

@@ -1,3 +1,4 @@
+# encoding: UTF-8
 require 'spec_helper'
 
 describe Zero::Response do
@@ -60,6 +61,13 @@ describe Zero::Response do
 
       subject.header['Content-Length'].should eq(6)
     end
+
+     it "sets the content_length to the bytesize of the message body" do
+      subject.body = ['föö', 'bär']
+      subject.content_length
+
+      subject.header['Content-Length'].should eq(9)
+    end
   end
 
 end