Smartmatch is experimental at t/1.t line 21.
t/1.t .. 
1..6
ok 1
ok 2
ok 3
ok 4
ok 5
[2021-12-16 12:59:25] listening for DNS queries on address 127.0.0.1 and port 18004
ok 6
ok
All tests successful.
Files=1, Tests=6,  0 wallclock secs ( 0.02 usr  0.00 sys +  0.28 cusr  0.02 csys =  0.32 CPU)
Result: PASS