From a048cbc4f0e81bcf8b24dbd96fdae41cd6c593b9 Mon Sep 17 00:00:00 2001
From: Ayaan Zaidi <hi@obviy.us>
Date: Thu, 28 May 2026 13:02:34 +0000
Subject: [PATCH] test(telegram): cover draft preview overflow

---
 extensions/telegram/src/draft-stream.test.ts | 75 +++++++++++++++++---
 1 file changed, 67 insertions(+), 8 deletions(-)

diff --git a/extensions/telegram/src/draft-stream.test.ts b/extensions/telegram/src/draft-stream.test.ts
index e790f747bea..a3466292c07 100644
--- a/extensions/telegram/src/draft-stream.test.ts
+++ b/extensions/telegram/src/draft-stream.test.ts
@@ -399,7 +399,42 @@ describe("createTelegramDraftStream", () => {
     });
   });
 
-  it("continues in a new message when rendered preview crosses maxChars", async () => {
+  it("keeps non-final overflow in one editable preview", async () => {
+    const api = createMockDraftApi();
+    const onSupersededPreview = vi.fn();
+    const stream = createDraftStream(api, { maxChars: 20, onSupersededPreview });
+
+    stream.update("Hello world");
+    await stream.flush();
+    stream.update("Hello world foo bar baz qux");
+    await stream.flush();
+
+    expect(api.sendMessage).toHaveBeenCalledTimes(1);
+    expect(api.sendMessage).toHaveBeenNthCalledWith(1, 123, "Hello world", undefined);
+    expect(api.editMessageText).toHaveBeenCalledWith(123, 17, "Hello world foo bar");
+    expect(onSupersededPreview).not.toHaveBeenCalled();
+    expect(stream.lastDeliveredText?.()).toBe("Hello world foo bar");
+  });
+
+  it("does not retain non-final overflow preview pages", async () => {
+    const api = createMockDraftApi();
+    const onSupersededPreview = vi.fn();
+    const stream = createDraftStream(api, {
+      maxChars: 20,
+      onSupersededPreview,
+    });
+
+    stream.update("Hello world");
+    await stream.flush();
+    stream.update("Hello world foo bar baz qux");
+    await stream.flush();
+
+    expect(api.sendMessage).toHaveBeenCalledTimes(1);
+    expect(api.editMessageText).toHaveBeenCalledWith(123, 17, "Hello world foo bar");
+    expect(onSupersededPreview).not.toHaveBeenCalled();
+  });
+
+  it("continues in a new message when a final rendered preview crosses maxChars", async () => {
     const api = createMockDraftApi();
     api.sendMessage
       .mockResolvedValueOnce({ message_id: 17 })
@@ -409,29 +444,53 @@ describe("createTelegramDraftStream", () => {
     stream.update("Hello world");
     await stream.flush();
     stream.update("Hello world foo bar baz qux");
-    await stream.flush();
+    await stream.stop();
 
     expect(api.sendMessage).toHaveBeenCalledTimes(2);
     expect(api.sendMessage).toHaveBeenNthCalledWith(1, 123, "Hello world", undefined);
     expect(api.sendMessage).toHaveBeenNthCalledWith(2, 123, "foo bar baz qux", undefined);
   });
 
-  it("splits a first oversized rendered preview into chained messages", async () => {
+  it("clamps a first oversized non-final preview", async () => {
     const api = createMockDraftApi();
-    api.sendMessage
-      .mockResolvedValueOnce({ message_id: 17 })
-      .mockResolvedValueOnce({ message_id: 42 });
     const stream = createDraftStream(api, { maxChars: 10 });
 
     stream.update("1234567890ABCDEFGHIJ");
     await stream.flush();
 
+    expect(api.sendMessage).toHaveBeenCalledTimes(1);
+    expect(api.sendMessage).toHaveBeenNthCalledWith(1, 123, "1234567890", undefined);
+    expect(stream.lastDeliveredText?.()).toBe("1234567890");
+  });
+
+  it("finalizes overflow that was hidden by a clamped non-final preview", async () => {
+    const api = createMockDraftApi();
+    api.sendMessage
+      .mockResolvedValueOnce({ message_id: 17 })
+      .mockResolvedValueOnce({ message_id: 42 });
+    const onSupersededPreview = vi.fn();
+    const stream = createDraftStream(api, {
+      maxChars: 10,
+      onSupersededPreview,
+    });
+
+    stream.update("1234567890ABCDEFGHIJ");
+    await stream.flush();
+    await stream.stop();
+
     expect(api.sendMessage).toHaveBeenCalledTimes(2);
     expect(api.sendMessage).toHaveBeenNthCalledWith(1, 123, "1234567890", undefined);
     expect(api.sendMessage).toHaveBeenNthCalledWith(2, 123, "ABCDEFGHIJ", undefined);
+    expect(stream.lastDeliveredText?.()).toBe("1234567890ABCDEFGHIJ");
+    expect(onSupersededPreview).toHaveBeenCalledWith(
+      expect.objectContaining({
+        messageId: 17,
+        retain: true,
+      }),
+    );
   });
 
-  it("retains overflow preview pages", async () => {
+  it("retains final overflow preview pages", async () => {
     const api = createMockDraftApi();
     api.sendMessage
       .mockResolvedValueOnce({ message_id: 17 })
@@ -445,7 +504,7 @@ describe("createTelegramDraftStream", () => {
     stream.update("Hello world");
     await stream.flush();
     stream.update("Hello world foo bar baz qux");
-    await stream.flush();
+    await stream.stop();
 
     expect(onSupersededPreview).toHaveBeenCalledTimes(1);
     const [supersededPreview] = onSupersededPreview.mock.calls.at(0) ?? [];