Retry dnssec-verify in kasp test code

It is possible that the zone is not yet fully signed because it is
signed in batches. Retry the AXFR and verify command a couple of times.

bin/tests/system/isctest/kasp.py

@@ -13,6 +13,7 @@ from functools import total_ordering
 import os
 from pathlib import Path
 import re
+import subprocess
 import time
 from typing import Optional, Union
 
@@ -21,7 +22,7 @@ from datetime import timedelta
 
 import dns
 import isctest.log
-
+import isctest.query
 
 DEFAULT_TTL = 300
 
@@ -29,7 +30,7 @@ DEFAULT_TTL = 300
 def _query(server, qname, qtype):
     query = dns.message.make_query(qname, qtype, use_edns=True, want_dnssec=True)
     try:
-        response = dns.query.tcp(query, server.ip, port=server.ports.dns, timeout=3)
+        response = isctest.query.tcp(query, server.ip, server.ports.dns, timeout=3)
     except dns.exception.Timeout:
         isctest.log.debug(f"query timeout for query {qname} {qtype} to {server.ip}")
         return None
@@ -278,21 +279,34 @@ def check_zone_is_signed(server, zone):
 def check_dnssec_verify(server, zone):
     # Check if zone if DNSSEC valid with dnssec-verify.
     fqdn = f"{zone}."
-    transfer = _query(server, fqdn, dns.rdatatype.AXFR)
-    if not isinstance(transfer, dns.message.Message):
-        isctest.log.debug(f"no response for {fqdn} AXFR from {server.ip}")
-    elif transfer.rcode() != dns.rcode.NOERROR:
-        rcode = dns.rcode.to_text(transfer.rcode())
-        isctest.log.debug(f"{rcode} response for {fqdn} AXFR from {server.ip}")
-    else:
-        zonefile = f"{zone}.axfr"
-        with open(zonefile, "w", encoding="utf-8") as file:
-            for rr in transfer.answer:
-                file.write(rr.to_text())
-                file.write("\n")
 
-    verify_command = [os.environ.get("VERIFY"), "-z", "-o", zone, zonefile]
-    isctest.run.cmd(verify_command)
+    verified = False
+    for _ in range(10):
+        transfer = _query(server, fqdn, dns.rdatatype.AXFR)
+        if not isinstance(transfer, dns.message.Message):
+            isctest.log.debug(f"no response for {fqdn} AXFR from {server.ip}")
+        elif transfer.rcode() != dns.rcode.NOERROR:
+            rcode = dns.rcode.to_text(transfer.rcode())
+            isctest.log.debug(f"{rcode} response for {fqdn} AXFR from {server.ip}")
+        else:
+            zonefile = f"{zone}.axfr"
+            with open(zonefile, "w", encoding="utf-8") as file:
+                for rr in transfer.answer:
+                    file.write(rr.to_text())
+                    file.write("\n")
+
+            try:
+                verify_command = [os.environ.get("VERIFY"), "-z", "-o", zone, zonefile]
+                verified = isctest.run.cmd(verify_command)
+            except subprocess.CalledProcessError:
+                pass
+
+        if verified:
+            break
+
+        time.sleep(1)
+
+    assert verified
 
 
 def check_dnssecstatus(server, zone, keys, policy=None, view=None):