Tests: cover shared Telegram draft stream state

src/telegram/draft-stream.test.ts

@@ -1,6 +1,7 @@
 import type { Bot } from "grammy";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import { createTelegramDraftStream } from "./draft-stream.js";
+import { importFreshModule } from "../../test/helpers/import-fresh.js";
+import { __testing, createTelegramDraftStream } from "./draft-stream.js";
 
 type TelegramDraftStreamParams = Parameters<typeof createTelegramDraftStream>[0];
 
@@ -65,6 +66,10 @@ function createForceNewMessageHarness(params: { throttleMs?: number } = {}) {
 }
 
 describe("createTelegramDraftStream", () => {
+  afterEach(() => {
+    __testing.resetTelegramDraftStreamForTests();
+  });
+
   it("sends stream preview message with message_thread_id when provided", async () => {
     const api = createMockDraftApi();
     const stream = createForumDraftStream(api);
@@ -355,6 +360,46 @@ describe("createTelegramDraftStream", () => {
     expect(api.editMessageText).not.toHaveBeenCalled();
   });
 
+  it("shares draft-id allocation across distinct module instances", async () => {
+    const draftA = await importFreshModule<typeof import("./draft-stream.js")>(
+      import.meta.url,
+      "./draft-stream.js?scope=shared-a",
+    );
+    const draftB = await importFreshModule<typeof import("./draft-stream.js")>(
+      import.meta.url,
+      "./draft-stream.js?scope=shared-b",
+    );
+    const apiA = createMockDraftApi();
+    const apiB = createMockDraftApi();
+
+    draftA.__testing.resetTelegramDraftStreamForTests();
+
+    try {
+      const streamA = draftA.createTelegramDraftStream({
+        api: apiA as unknown as Bot["api"],
+        chatId: 123,
+        thread: { id: 42, scope: "dm" },
+        previewTransport: "draft",
+      });
+      const streamB = draftB.createTelegramDraftStream({
+        api: apiB as unknown as Bot["api"],
+        chatId: 123,
+        thread: { id: 42, scope: "dm" },
+        previewTransport: "draft",
+      });
+
+      streamA.update("Message A");
+      await streamA.flush();
+      streamB.update("Message B");
+      await streamB.flush();
+
+      expect(apiA.sendMessageDraft.mock.calls[0]?.[1]).toBe(1);
+      expect(apiB.sendMessageDraft.mock.calls[0]?.[1]).toBe(2);
+    } finally {
+      draftA.__testing.resetTelegramDraftStreamForTests();
+    }
+  });
+
   it("creates new message after forceNewMessage is called", async () => {
     const { api, stream } = createForceNewMessageHarness();