my $kdf = File::KDBX::KDF->new(uuid => KDF_UUID_AES, seed => "\1" x 32, rounds => 10);
-ok !File::KDBX::_XS_LOADED(), 'XS can be avoided';
+ok !File::KDBX::XS->can('kdf_aes_transform_half'), 'XS can be avoided';
my $r = $kdf->transform("\2" x 32);
is $r, "\342\234cp\375\\p\253]\213\f\246\345\230\266\260\r\222j\332Z\204:\322 p\224mhm\360\222",