my $bar = Bar->new;
isa_ok($bar, 'Bar');
-ok ! exception {
+is( exception {
$bar->foo('Foo');
-}, '... checked the type constraint correctly';
+}, undef, '... checked the type constraint correctly' );
-ok exception {
+isnt( exception {
$bar->foo(Foo->new);
-}, '... checked the type constraint correctly';
+}, undef, '... checked the type constraint correctly' );
done_testing;