fix: resolve heartbeat sender and Slack thread_ts

src/slack/monitor/thread-resolution.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, it, vi } from "vitest";
+
+import type { SlackMessageEvent } from "../types.js";
+import { createSlackThreadTsResolver } from "./thread-resolution.js";
+
+describe("createSlackThreadTsResolver", () => {
+  it("caches resolved thread_ts lookups", async () => {
+    const historyMock = vi.fn().mockResolvedValue({
+      messages: [{ ts: "1", thread_ts: "9" }],
+    });
+    const resolver = createSlackThreadTsResolver({
+      client: { conversations: { history: historyMock } } as any,
+      cacheTtlMs: 60_000,
+      maxSize: 5,
+    });
+
+    const message = {
+      channel: "C1",
+      parent_user_id: "U2",
+      ts: "1",
+    } as SlackMessageEvent;
+
+    const first = await resolver.resolve({ message, source: "message" });
+    const second = await resolver.resolve({ message, source: "message" });
+
+    expect(first.thread_ts).toBe("9");
+    expect(second.thread_ts).toBe("9");
+    expect(historyMock).toHaveBeenCalledTimes(1);
+  });
+});