unslothai--unsloth/studio/backend/tests/test_tool_message_empty_content.py

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0

"""Empty ``role="tool"`` content must be accepted on the OpenAI-compat surface.

Agentic clients send ``content: ""`` when a command produced no output;
OpenAI and llama-server both accept it. Studio used to 400, which standard
clients treat as non-retryable and kill the session. The validator must
normalize empty/missing tool content to ``""`` instead of raising.
"""

from __future__ import annotations

import sys
from pathlib import Path

import pytest

_BACKEND_DIR = str(Path(__file__).resolve().parent.parent)
if _BACKEND_DIR not in sys.path:
    sys.path.insert(0, _BACKEND_DIR)

from models.inference import ChatMessage


def test_tool_message_empty_string_content_is_accepted():
    msg = ChatMessage(role = "tool", content = "", tool_call_id = "call_1")
    assert msg.content == ""


def test_tool_message_none_content_normalizes_to_empty_string():
    msg = ChatMessage(role = "tool", content = None, tool_call_id = "call_1")
    assert msg.content == ""


def test_tool_message_empty_list_content_normalizes_to_empty_string():
    msg = ChatMessage(role = "tool", content = [], tool_call_id = "call_1")
    assert msg.content == ""


def test_tool_message_real_content_is_preserved():
    msg = ChatMessage(role = "tool", content = "ok", tool_call_id = "call_1")
    assert msg.content == "ok"


def test_user_message_still_requires_content():
    with pytest.raises(ValueError):
        ChatMessage(role = "user", content = None)


def test_assistant_empty_content_still_collapses_to_none():
    msg = ChatMessage(role = "assistant", content = "")
    assert msg.content is None