+my $old_afi;
+
+foreach my $tag ( @tags ) {
+
+ ok( my $blocks = $o->read_blocks( $tag ), "read_blocks $tag" );
+
+ ok( my $afi = $o->read_afi( $tag ), "read_afi $tag" );
+
+ ok( $o->write_blocks( $tag, $blocks->{$tag} ), "write_blocks $tag" );
+
+ my $new_afi = "\x42";
+
+ ok( $o->write_afi( $tag, $new_afi ), sprintf( "write_afi %s %x", $tag, $new_afi ) );
+
+ cmp_ok( $o->read_afi( $tag ), 'eq', $new_afi, 'AFI check' );
+
+ ok( $o->write_afi( $tag, $afi ), sprintf( "write_afi %s %x", $tag, $afi ) );
+
+}
+
+done_testing();