Unit test for NSID support

MANIFEST

@@ -182,6 +182,7 @@ t/example.org
 t/idn.t
 t/load_zonefile.t
 t/netldns.t
+t/nsid.t
 t/packet.t
 t/regression.t
 t/resolver.t

t/nsid.t

@@ -0,0 +1,22 @@
+use strict;
+use warnings;
+
+use Test::More;
+use Zonemaster::LDNS;
+
+SKIP: {
+    skip 'no network', 1 unless $ENV{TEST_WITH_NETWORK};
+
+    my $host = '192.134.4.1'; #ns1.nic.fr with nsid: ns1.th3.nic.fr
+    my $expected_nsid = "ns1.th3.nic.fr";
+
+    my $pkt = Zonemaster::LDNS::Packet->new('domain.example');
+    $pkt->nsid; # set the NSID EDNS option
+    my $res = Zonemaster::LDNS->new($host)->query_with_pkt($pkt);
+
+    my $nsid = $res->get_nsid();
+
+    is( $nsid, $expected_nsid, 'Correct NSID' );
+};
+
+done_testing();