fix(gateway): isolate telegram forum topic sessions

tests/tools/test_send_message_tool.py

@@ -0,0 +1,67 @@
+"""Tests for tools/send_message_tool.py."""
+
+import asyncio
+import json
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, patch
+
+from gateway.config import Platform
+from tools.send_message_tool import send_message_tool
+
+
+def _run_async_immediately(coro):
+    return asyncio.run(coro)
+
+
+def _make_config():
+    telegram_cfg = SimpleNamespace(enabled=True, token="fake-token", extra={})
+    return SimpleNamespace(
+        platforms={Platform.TELEGRAM: telegram_cfg},
+        get_home_channel=lambda _platform: None,
+    ), telegram_cfg
+
+
+class TestSendMessageTool:
+    def test_sends_to_explicit_telegram_topic_target(self):
+        config, telegram_cfg = _make_config()
+
+        with patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch("model_tools._run_async", side_effect=_run_async_immediately), \
+             patch("tools.send_message_tool._send_to_platform", new=AsyncMock(return_value={"success": True})) as send_mock, \
+             patch("gateway.mirror.mirror_to_session", return_value=True) as mirror_mock:
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "telegram:-1001:17585",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        send_mock.assert_awaited_once_with(Platform.TELEGRAM, telegram_cfg, "-1001", "hello", thread_id="17585")
+        mirror_mock.assert_called_once_with("telegram", "-1001", "hello", source_label="cli", thread_id="17585")
+
+    def test_resolved_telegram_topic_name_preserves_thread_id(self):
+        config, telegram_cfg = _make_config()
+
+        with patch("gateway.config.load_gateway_config", return_value=config), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch("gateway.channel_directory.resolve_channel_name", return_value="-1001:17585"), \
+             patch("model_tools._run_async", side_effect=_run_async_immediately), \
+             patch("tools.send_message_tool._send_to_platform", new=AsyncMock(return_value={"success": True})) as send_mock, \
+             patch("gateway.mirror.mirror_to_session", return_value=True):
+            result = json.loads(
+                send_message_tool(
+                    {
+                        "action": "send",
+                        "target": "telegram:Coaching Chat / topic 17585",
+                        "message": "hello",
+                    }
+                )
+            )
+
+        assert result["success"] is True
+        send_mock.assert_awaited_once_with(Platform.TELEGRAM, telegram_cfg, "-1001", "hello", thread_id="17585")