--- /dev/null
+use strict;
+use warnings;
+use Test::More tests => 5;
+
+{
+ package Request::Headers::Role;
+ use Mouse::Role;
+ has 'foo' => ( is => 'rw' );
+}
+
+{
+ package Request::Headers;
+ use Mouse;
+ with 'Request::Headers::Role';
+}
+
+{
+ package Response::Headers::Role;
+ use Mouse::Role;
+ has 'foo' => ( is => 'rw' );
+}
+
+{
+ package Response::Headers;
+ use Mouse;
+ with 'Response::Headers::Role';
+}
+
+{
+ package Response;
+ use Mouse;
+ use Mouse::TypeRegistry;
+
+ role_type Headers => { role => 'Response::Headers::Role' };
+ coerce 'Headers' => +{
+ HashRef => sub {
+ Response::Headers->new(%{ $_ });
+ },
+ };
+
+ has headers => (
+ is => 'rw',
+ isa => 'Headers',
+ coerce => 1,
+ );
+}
+
+my $res = Response->new(headers => { foo => 'bar' });
+isa_ok($res->headers, 'Response::Headers');
+is($res->headers->foo, 'bar');
+$res->headers({foo => 'yay'});
+isa_ok($res->headers, 'Response::Headers');
+is($res->headers->foo, 'yay');
+
+eval {
+ $res->headers( Request::Headers->new( foo => 'baz' ) );
+};
+ok $@;