Add test_deep_search_agent.py

test_deep_search_agent.py

@@ -0,0 +1,11 @@
+from deep_search_agent import ScratchDeepAgent
+
+
+def test_agent_creates_and_flushes_virtual_files(tmp_path):
+    agent = ScratchDeepAgent()
+    report = agent.run("LangGraph")
+    written = agent.flush_files(str(tmp_path))
+
+    assert "Search report" in report
+    assert "report.md" in agent.virtual_files
+    assert all(path.exists() for path in written)