From 928357f221fc45ed05401c73c0b156e97f591675 Mon Sep 17 00:00:00 2001
From: Danijel Martinek <danijel@fraqtal.xyz>
Date: Fri, 8 May 2026 21:56:18 +0200
Subject: [PATCH] feat(core-testing): RecordingRealtimeBroadcaster
 (local-type-alias pattern)

---
 .../core-testing/src/instrumentation/index.ts |  1 +
 .../recording-realtime-broadcaster.test.ts    | 27 +++++++++++++++++
 .../recording-realtime-broadcaster.ts         | 29 +++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 packages/core-testing/src/instrumentation/recording-realtime-broadcaster.test.ts
 create mode 100644 packages/core-testing/src/instrumentation/recording-realtime-broadcaster.ts

diff --git a/packages/core-testing/src/instrumentation/index.ts b/packages/core-testing/src/instrumentation/index.ts
index 053357c..60ee39f 100644
--- a/packages/core-testing/src/instrumentation/index.ts
+++ b/packages/core-testing/src/instrumentation/index.ts
@@ -2,3 +2,4 @@ export { RecordingTracer, type RecordedSpan } from "./recording-tracer";
 export { RecordingLogger, type RecordedCapture } from "./recording-logger";
 export { RecordingJobQueue } from "./recording-job-queue";
 export { RecordingEventBus } from "./recording-event-bus";
+export { RecordingRealtimeBroadcaster } from "./recording-realtime-broadcaster";
diff --git a/packages/core-testing/src/instrumentation/recording-realtime-broadcaster.test.ts b/packages/core-testing/src/instrumentation/recording-realtime-broadcaster.test.ts
new file mode 100644
index 0000000..1e3d14b
--- /dev/null
+++ b/packages/core-testing/src/instrumentation/recording-realtime-broadcaster.test.ts
@@ -0,0 +1,27 @@
+import { describe, it, expect } from "vitest";
+import { z } from "zod";
+import { RecordingRealtimeBroadcaster } from "@/instrumentation/recording-realtime-broadcaster";
+
+const ch = {
+  name: "test.ch" as const,
+  schema: z.object({ x: z.number() }).strict(),
+  scope: "public" as const,
+};
+
+describe("RecordingRealtimeBroadcaster", () => {
+  it("records every broadcast call after schema validation", async () => {
+    const b = new RecordingRealtimeBroadcaster();
+    await b.broadcast(ch, { x: 1 });
+    await b.broadcast(ch, { x: 2 });
+    expect(b.broadcasts).toEqual([
+      { channel: "test.ch", payload: { x: 1 } },
+      { channel: "test.ch", payload: { x: 2 } },
+    ]);
+  });
+
+  it("rejects payloads that fail schema validation", async () => {
+    const b = new RecordingRealtimeBroadcaster();
+    await expect(b.broadcast(ch, { x: "wrong" } as never)).rejects.toThrow();
+    expect(b.broadcasts).toHaveLength(0);
+  });
+});
diff --git a/packages/core-testing/src/instrumentation/recording-realtime-broadcaster.ts b/packages/core-testing/src/instrumentation/recording-realtime-broadcaster.ts
new file mode 100644
index 0000000..2ea6ce8
--- /dev/null
+++ b/packages/core-testing/src/instrumentation/recording-realtime-broadcaster.ts
@@ -0,0 +1,29 @@
+// Local type aliases mirroring @repo/core-realtime's contracts. Kept inline to
+// avoid a build-graph cycle between core-testing (tooling) and core-realtime (core).
+// Same pattern recording-event-bus + recording-job-queue use.
+import type { z } from "zod";
+
+type RealtimeChannelDescriptor<TName extends string, TSchema extends z.ZodType> = {
+  readonly name: TName;
+  readonly schema: TSchema;
+  readonly scope?: string;
+};
+
+interface IRealtimeBroadcaster {
+  broadcast<T>(
+    descriptor: RealtimeChannelDescriptor<string, z.ZodType<T>>,
+    payload: T,
+  ): Promise<void>;
+}
+
+export class RecordingRealtimeBroadcaster implements IRealtimeBroadcaster {
+  readonly broadcasts: { channel: string; payload: unknown }[] = [];
+
+  async broadcast<T>(
+    descriptor: RealtimeChannelDescriptor<string, z.ZodType<T>>,
+    payload: T,
+  ): Promise<void> {
+    descriptor.schema.parse(payload);
+    this.broadcasts.push({ channel: descriptor.name, payload });
+  }
+}