fixup! Port TCP request statistics checks to Python

Assisted-by: Claude:claude-fable-5

diff --git a/bin/tests/system/tcp/tests_tcp.py b/bin/tests/system/tcp/tests_tcp.py
index 0e6b96e6a73425b797d50b76e0d7876c25edd9f3..b788a96d62ce31a40b7ed450f74e6bbf90c92462 100644 (file)
--- a/bin/tests/system/tcp/tests_tcp.py
+++ b/bin/tests/system/tcp/tests_tcp.py
@@ -24,6 +24,7 @@ import time
 import dns.message
 import dns.name
 import dns.query
+import dns.rcode
 import dns.rrset
 import pytest
 
@@ -369,6 +370,24 @@ def test_tcp_big(named_port: int) -> None:
         tcp_round_trip(sock, msg)
 
 
+def wait_for_stable_tcp_requests(ns: NamedInstance, timeout: int = 10) -> int:
+    """Read the TCP request counter until it stops changing.
+
+    The counter is incremented on request receipt, so a client response
+    implies its upstream queries are already counted; this only needs to
+    absorb unsynchronized traffic such as the resolver's root priming query.
+    """
+    last = -1
+
+    def stable() -> bool:
+        nonlocal last
+        previous, last = last, tcp_requests_received(ns)
+        return previous == last
+
+    isctest.run.retry_with_timeout(stable, timeout=timeout)
+    return last
+
+
 def test_tcp_request_statistics(
     ns1: NamedInstance, ns2: NamedInstance, ns3: NamedInstance, ns4: NamedInstance
 ) -> None:
@@ -378,21 +397,19 @@ def test_tcp_request_statistics(
 
     isctest.log.info("checking TCP request statistics (resolver)")
     msg = isctest.query.create("txt.example.", "A")
-    isctest.query.udp(msg, ns3.ip)
-    time.sleep(1)
+    isctest.query.udp(msg, ns3.ip, expected_rcode=dns.rcode.NXDOMAIN)
 
-    ns1_tcp_after_resolver = tcp_requests_received(ns1)
-    ns2_tcp_after_resolver = tcp_requests_received(ns2)
+    ns1_tcp_after_resolver = wait_for_stable_tcp_requests(ns1)
+    ns2_tcp_after_resolver = wait_for_stable_tcp_requests(ns2)
     assert ns1_tcp < ns1_tcp_after_resolver
     assert ns2_tcp == ns2_tcp_after_resolver
 
     isctest.log.info("checking TCP request statistics (forwarder)")
     msg = isctest.query.create("txt.example.", "A")
-    isctest.query.udp(msg, ns4.ip)
-    time.sleep(1)
+    isctest.query.udp(msg, ns4.ip, expected_rcode=dns.rcode.NXDOMAIN)
 
-    ns1_tcp_after_forwarder = tcp_requests_received(ns1)
-    ns2_tcp_after_forwarder = tcp_requests_received(ns2)
+    ns1_tcp_after_forwarder = wait_for_stable_tcp_requests(ns1)
+    ns2_tcp_after_forwarder = wait_for_stable_tcp_requests(ns2)
     assert ns1_tcp_after_resolver == ns1_tcp_after_forwarder
     assert ns2_tcp_after_resolver < ns2_tcp_after_forwarder