fixed xml_escape to use character semantics

Changes

@@ -12,6 +12,7 @@ This file documents the revision history for Perl extension Mojo.
           defensive and made them in turn 20 times faster.
         - Fixed keep alive problem in Mojo::Transaction::Pipeline.
         - Fixed and simplified Mojo::Parameters. (gbarr)
+        - Fixed xml_escape to use character semantics. (vti)
         - Fixed body helper in Mojo::Message and added tests. (vti)
         - Fixed padding byte handling in Mojo::Server::FastCGI.
           (Jaroslav Muhin)

lib/Mojo/ByteStream.pm

@@ -503,6 +503,9 @@ sub url_unescape {
 sub xml_escape {
     my $self = shift;
 
+    # Character semantics
+    no bytes;
+
     # Replace "&", "<", ">", """ and "'"
     for ($self->{bytestream}) {
         s/&/&amp;/g;

t/mojo/bytestream.t

@@ -5,10 +5,12 @@
 use strict;
 use warnings;
 
+use utf8;
+
 # Homer, we're going to ask you a few simple yes or no questions.
 # Do you understand?
 # Yes. *lie dectector blows up*
-use Test::More tests => 30;
+use Test::More tests => 32;
 
 use_ok('Mojo::ByteStream', 'b');
 
@@ -121,3 +123,11 @@ is("$stream", '/usr/local/lib/perl5/site_perl/5.10.0/Mojo/ByteStream.pm');
 # xml_escape
 $stream = b(qq/la<f>\nbar"baz"'yada\n'&lt;la/)->xml_escape;
 is("$stream", "la&lt;f&gt;\nbar&quot;baz&quot;&apos;yada\n&apos;&amp;lt;la");
+
+# utf8 xml_escape with nothing to escape
+$stream = b(qq/привет/)->xml_escape;
+is("$stream", "привет");
+
+# utf8 xml_escape
+$stream = b(qq/привет<foo>/)->xml_escape;
+is("$stream", "привет&lt;foo&gt;");