[Tests] Add integration tests for file upload endpoint POST /sessions/{session_id}/message/upload

[Nikitaa104]

What feature do you want to see added?

Problem

The file upload endpoint POST /sessions/{session_id}/message/upload has
unit tests in tests/unit/routes/test_file_upload.py but zero integration
tests in tests/integration/.

Missing Integration Test Cases

• Upload a text file to a valid session—returns 200 with reply
• Upload an image file to a valid session—returns 200 with reply
• Upload to a nonexistent session—returns 404
• Upload with empty message and no files—returns 422
• Upload unsupported file type—returns 400
• Full lifecycle: create session → upload file → delete session

Proposed Solution

Add integration tests to `tests/integration/test_chatbot.py the following:
existing conventions in that file.

Are you interested in contributing a fix?

Yes—I will submit a PR once this approach is approved.

@berviantoleo does this look good to proceed?

Upstream changes

No response

Are you interested in contributing this feature?

yes.

[Nikitaa104]

Hi @berviantoleo, I opened this issue and have submitted PR #237 to address it. I noticed that PR #236 was also submitted around the same time—I wasn't aware someone else was working on this. Both PRs aim to close the same issue, so I wanted to flag this for your awareness. Happy to collaborate with @himanshu748 on how to proceed. Thank you!