Add a test for deprecated feature

diff --git a/t/990_deprecated/990-undefined-class-type.t b/t/990_deprecated/990-undefined-class-type.t
new file mode 100755 (executable)
index 0000000..4a5e314
--- /dev/null
+++ b/t/990_deprecated/990-undefined-class-type.t
@@ -0,0 +1,26 @@
+#!perl\r
+\r
+use strict;
+use warnings;
+use Test::More tests => 5;\r
+\r
+use Mouse::Util::TypeConstraints;\r
+
+my $z = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint('My::New::Class | Str');
+\r
+#diag $z->dump;\r
+
+eval q{
+    package My::New::Class;
+    use Mouse;
+    package My::New::DerivedClass;
+    use Mouse;
+    extends 'My::New::Class';
+};
+
+ok $z->check(My::New::Class->new);
+ok $z->check(My::New::DerivedClass->new);
+ok $z->check('Foo');
+ok!$z->check(undef);
+ok!$z->check(bless {}, 'Foo');
+