Add unit tests for web fetching tools

backend/tests/test_agent_web_tools.py

@@ -0,0 +1,46 @@
+import asyncio
+import unittest
+from unittest.mock import AsyncMock, patch
+
+from backend.agent.registry import NativeToolProvider, ToolExecutionContext
+from backend.agent.tools.web import FETCH_TEXT_LIMIT, register_web_tools
+
+
+def context(registry):
+    return ToolExecutionContext(
+        run_id="run",
+        workflow_id="workflow",
+        node_id="fetch",
+        session_id=None,
+        selection_mode="explicit",
+        explicit_user_action=True,
+        emit=lambda *_args: asyncio.sleep(0),
+        cancellation_event=asyncio.Event(),
+        db_factory=lambda: None,
+        registry=registry,
+    )
+
+
+class WebToolTests(unittest.IsolatedAsyncioTestCase):
+    async def test_fetch_accepts_search_result_batches_and_caps_page_text(self):
+        registry = NativeToolProvider()
+        register_web_tools(registry)
+        urls = [{"url": f"https://example.test/{index}"} for index in range(16)]
+
+        async def fake_fetch(url):
+            return {
+                "requested_url": url,
+                "url": url,
+                "title": "Example",
+                "text": "x" * (FETCH_TEXT_LIMIT + 500),
+            }
+
+        with patch("backend.agent.tools.web.fetch_website_snapshot", new=AsyncMock(side_effect=fake_fetch)):
+            result = await registry.call_tool(
+                "heimgeist.web_fetch",
+                {"url": None, "urls": urls, "maximum_pages": 6},
+                context(registry),
+            )
+
+        self.assertEqual(len(result["pages"]), 6)
+        self.assertTrue(all(len(page["cleaned_text"]) == FETCH_TEXT_LIMIT for page in result["pages"]))