From 92f2566d2c49d4bf548405b3d9a71be87480cc6c Mon Sep 17 00:00:00 2001
From: Meta Vens <rwvens@hotmail.com>
Date: Wed, 23 Sep 2026 15:21:03 +0200
Subject: [PATCH] Fix the golden-bytes lane to match by sequence, not assume
 frame 1
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Found by a real failure on the Linux verification container: latest-only
coalesces on both the provider's outbox and the managed connector's own
receive-side inbox, so a single ReceiveAsync() call is not guaranteed to
land on the first frame broadcast — on a slower host it landed on sequence 3.
The C# test now also prints CULTMESH_GOLDEN_SEQUENCE, and the harness looks
up the TypeScript peer's logged encoding of that same sequence instead of
hardcoding sent === 1.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
---
 .../test/interop/cultnet-interop.test.ts      | 21 ++++++++++++-------
 .../CultMeshQuicRealtimeTransportTests.cs     |  7 +++++++
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/packages/cultnet-ts/test/interop/cultnet-interop.test.ts b/packages/cultnet-ts/test/interop/cultnet-interop.test.ts
index c72deaff..940fcaf4 100644
--- a/packages/cultnet-ts/test/interop/cultnet-interop.test.ts
+++ b/packages/cultnet-ts/test/interop/cultnet-interop.test.ts
@@ -548,13 +548,18 @@ test("CultMesh QUIC realtime: TypeScript provider and C# managed connector, with
   assert.match(stdout, /Passed:\s*1/, `expected exactly one passed test.\n${stdout}`);
   assert.doesNotMatch(stdout, /Skipped:\s*1/, `the env var should have made the test run, not skip.\n${stdout}`);
 
-  const goldenMatch = /CULTMESH_GOLDEN_HEX=([0-9A-Fa-f]+)/.exec(stdout);
-  assert.ok(goldenMatch, `expected the C# test to print its golden hex line.\n${stdout}`);
-  const csharpHex = goldenMatch![1].toLowerCase();
+  const goldenHexMatch = /CULTMESH_GOLDEN_HEX=([0-9A-Fa-f]+)/.exec(stdout);
+  const goldenSequenceMatch = /CULTMESH_GOLDEN_SEQUENCE=(\d+)/.exec(stdout);
+  assert.ok(goldenHexMatch, `expected the C# test to print its golden hex line.\n${stdout}`);
+  assert.ok(goldenSequenceMatch, `expected the C# test to print which sequence it received.\n${stdout}`);
+  const csharpHex = goldenHexMatch![1].toLowerCase();
+  const csharpSequence = Number(goldenSequenceMatch![1]);
 
-  // The typescript peer logs the hex of its own encoding of frame 1 (the
-  // first, and here the only, frame the managed connector's single
-  // ReceiveAsync call can have gotten) to stderr as it sends it.
+  // Which frame the managed connector's single ReceiveAsync() call actually
+  // got is not pinned to frame 1: latest-only coalesces on both the
+  // provider's outbox and the connector's own receive-side inbox, so a slow
+  // start can land on a later sequence. Match the typescript peer's logged
+  // encoding of that same sequence rather than assuming the first one sent.
   const tsSentLine = server.stderr
     .join("")
     .split("\n")
@@ -567,8 +572,8 @@ test("CultMesh QUIC realtime: TypeScript provider and C# managed connector, with
         return undefined;
       }
     })
-    .find((entry) => entry?.event === "quic-realtime-serve" && entry.sent === 1);
-  assert.ok(tsSentLine?.hex, "expected the typescript peer to log frame 1's hex encoding");
+    .find((entry) => entry?.event === "quic-realtime-serve" && entry.sent === csharpSequence);
+  assert.ok(tsSentLine?.hex, `expected the typescript peer to log frame ${csharpSequence}'s hex encoding`);
 
   assert.equal(csharpHex, tsSentLine!.hex, "TypeScript and C# must encode the same frame identically");
 });
diff --git a/tests/GameCult.Mesh.Quic.Tests/CultMeshQuicRealtimeTransportTests.cs b/tests/GameCult.Mesh.Quic.Tests/CultMeshQuicRealtimeTransportTests.cs
index 1ff6fd20..a10c9671 100644
--- a/tests/GameCult.Mesh.Quic.Tests/CultMeshQuicRealtimeTransportTests.cs
+++ b/tests/GameCult.Mesh.Quic.Tests/CultMeshQuicRealtimeTransportTests.cs
@@ -193,7 +193,14 @@ public sealed class CultMeshQuicRealtimeTransportTests
             frame.BodyId.Should().NotBeNullOrWhiteSpace();
             frame.Payload.Should().NotBeEmpty();
 
+            // Which frame this actually is is not pinned to the provider's
+            // first broadcast: latest-only coalesces on both the provider's
+            // outbox and this connector's own receive-side inbox, so a
+            // single ReceiveAsync() can land on whichever sequence was
+            // latest by the time it was called. The harness matches by
+            // sequence rather than assuming the first frame sent.
             var hex = Convert.ToHexString(CultMeshRealtimeWireProtocol.EncodeFrame(frame));
+            TestContext.Out.WriteLine($"CULTMESH_GOLDEN_SEQUENCE={frame.Sequence}");
             TestContext.Out.WriteLine($"CULTMESH_GOLDEN_HEX={hex}");
         }
         finally