Test fixtures: the Rust owner's Idunn runtime records, and one fake Idunn RUDP endpoint

tests/fixtures/idunn-runtime holds expected.cc, activation.cc, the activation seed,
the presence identity credential and the machine-id it is bound to, copied from
CultLib 217a9480 (Rust-written; test keys only). fake-idunn-rudp.ts is the accept
server idunn-rudp-health.test.ts built inline, now keeping a session per remote and
every delivered frame, so a boot test can receive several pulses.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/fixtures/fake-idunn-rudp.ts

@@ -0,0 +1,64 @@
+/**
+ * A stand-in for Idunn's health endpoint: it accepts each RUDP connect, acks
+ * the frame that follows and keeps every delivered frame. Heimdall opens a
+ * fresh socket and session per publication, so sessions are kept per remote.
+ */
+import dgram from "node:dgram";
+import {
+  CultNetRudpSession,
+  decodeRudpPacket,
+  encodeRudpPacket,
+  type CultNetTransportFrame,
+} from "cultnet-ts";
+
+export interface FakeIdunnRudp {
+  port: number;
+  frames: CultNetTransportFrame[];
+  /** Resolves with the nth delivered frame (0-based) once it has arrived. */
+  frame(index: number): Promise<CultNetTransportFrame>;
+  close(): void;
+}
+
+export async function startFakeIdunnRudp(): Promise<FakeIdunnRudp> {
+  const server = dgram.createSocket("udp4");
+  const sessions = new Map<string, CultNetRudpSession>();
+  const frames: CultNetTransportFrame[] = [];
+  const waiting: Array<{ index: number; resolve: (frame: CultNetTransportFrame) => void }> = [];
+
+  server.on("message", (wire, remote) => {
+    const packet = decodeRudpPacket(wire);
+    const key = `${remote.address}:${remote.port}`;
+    if (packet.packetType === "connect") {
+      const session = new CultNetRudpSession({
+        connectionId: 0x1d0d0001,
+        initialSequence: 1,
+        resendDelayMs: 100,
+      });
+      sessions.set(key, session);
+      server.send(encodeRudpPacket(session.acceptConnect(packet, Date.now())), remote.port, remote.address);
+      return;
+    }
+    const session = sessions.get(key);
+    if (!session) return;
+    const result = session.receive(packet, Date.now());
+    if (result.reply) server.send(encodeRudpPacket(result.reply), remote.port, remote.address);
+    for (const frame of result.delivered) {
+      frames.push(frame);
+      for (const waiter of waiting.filter((entry) => entry.index === frames.length - 1)) waiter.resolve(frame);
+    }
+    if (result.delivered.length > 0) {
+      server.send(encodeRudpPacket(session.createAck()), remote.port, remote.address);
+    }
+  });
+  await new Promise<void>((resolve) => server.bind(0, "127.0.0.1", resolve));
+
+  return {
+    port: server.address().port,
+    frames,
+    frame: (index) =>
+      frames[index]
+        ? Promise.resolve(frames[index]!)
+        : new Promise((resolve) => waiting.push({ index, resolve })),
+    close: () => server.close(),
+  };
+}

tests/fixtures/idunn-runtime/.gitattributes

@@ -0,0 +1 @@
+* -text

tests/fixtures/idunn-runtime/README.md

@@ -0,0 +1,11 @@
+# Idunn runtime fixtures
+
+Written by the Rust owner, not by Heimdall's tests. Copied byte for byte from CultLib
+`217a9480`, `packages/cultnet-ts/test/fixtures/idunn-runtime/web` (`expected.cc`,
+`activation.cc`, `activation-key.seed`, `provider-identity.credential`) and that directory's
+`machine-id`. CultLib regenerates them with `packages/cultnet-rs/examples/idunn_runtime_fixture.rs`
+(its own README has the Yggdrasil command); the provider identity is bound to `machine-id`, so a
+test that decodes it supplies that machine id instead of `/etc/machine-id`.
+
+Every key here is a test key. `provider-identity.credential` is the shape Idunn passes on the
+presence-identity descriptor: key fields are 32-integer arrays, which only the Rust owner writes.

tests/fixtures/idunn-runtime/activation-key.seed

@@ -0,0 +1 @@
+¯ÂOd×f¯l*oµ‘ÀFªv‰n<E280B0>hLûÑpšS
´p

tests/fixtures/idunn-runtime/machine-id

@@ -0,0 +1 @@
+c1c1c1c1c1c1c1c1c1c1c1c1c1c1c1c1

tests/idunn-rudp-health.test.ts

@@ -1,18 +1,12 @@
-import dgram from "node:dgram";
 import { mkdtemp } from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import { decode } from "@msgpack/msgpack";
-import {
+import { parseCultNetMessage } from "cultnet-ts";
-  CultNetRudpSession,
-  decodeRudpPacket,
-  encodeRudpPacket,
-  parseCultNetMessage,
-  type CultNetTransportFrame,
-} from "cultnet-ts";
 import { describe, expect, it, vi } from "vitest";
 import { loadConfig } from "../src/config.js";
 import { publishIdunnRudpHealth } from "../src/idunn-rudp-health.js";
+import { startFakeIdunnRudp } from "./fixtures/fake-idunn-rudp.js";
 
 vi.mock("node:fs/promises", async (importOriginal) => {
   const original = await importOriginal<typeof import("node:fs/promises")>();
@@ -27,37 +21,12 @@ vi.mock("node:fs/promises", async (importOriginal) => {
 
 describe("Heimdall Idunn health publication", () => {
   it("completes the canonical RUDP handshake before publishing its signed frame", async () => {
-    const server = dgram.createSocket("udp4");
+    const server = await startFakeIdunnRudp();
-    const session = new CultNetRudpSession({
-      connectionId: 0x1d0d0001,
-      initialSequence: 1,
-      resendDelayMs: 100,
-    });
-    let resolveFrame!: (frame: CultNetTransportFrame) => void;
-    const frameReceived = new Promise<CultNetTransportFrame>((resolve) => {
-      resolveFrame = resolve;
-    });
-
-    server.on("message", (wire, remote) => {
-      const packet = decodeRudpPacket(wire);
-      if (packet.packetType === "connect") {
-        server.send(encodeRudpPacket(session.acceptConnect(packet, Date.now())), remote.port, remote.address);
-        return;
-      }
-      const result = session.receive(packet, Date.now());
-      if (result.reply) server.send(encodeRudpPacket(result.reply), remote.port, remote.address);
-      for (const frame of result.delivered) resolveFrame(frame);
-      if (result.delivered.length > 0) {
-        server.send(encodeRudpPacket(session.createAck()), remote.port, remote.address);
-      }
-    });
-    await new Promise<void>((resolve) => server.bind(0, "127.0.0.1", resolve));
 
     try {
       const tmp = await mkdtemp(path.join(os.tmpdir(), "heimdall-idunn-rudp-"));
-      const address = server.address();
       const config = loadConfig({
-        GC_ACCESS_IDUNN_RUDP_HEALTH: `127.0.0.1:${address.port}`,
+        GC_ACCESS_IDUNN_RUDP_HEALTH: `127.0.0.1:${server.port}`,
         GC_ACCESS_PROVIDER_HEALTH_IDENTITY_PATH: path.join(tmp, "provider-health-identity.cc"),
       });
       const observedAt = "2026-08-22T00:45:00.000Z";
@@ -78,7 +47,7 @@ describe("Heimdall Idunn health publication", () => {
         observedAt,
         presence,
       });
-      const frame = await frameReceived;
+      const frame = await server.frame(0);
       const message = parseCultNetMessage(decode(frame.payload), "cultnet.schema.v0");
 
       expect(frame.channelId).toBe("schema");