test(gateway): pin SQLite-only load_transcript behaviour

tests/gateway/test_load_transcript_db_only.py

@@ -0,0 +1,27 @@
+"""Verify load_transcript returns SQLite messages without any JSONL file."""
+from pathlib import Path
+import pytest
+
+from gateway.session import SessionStore
+from gateway.config import GatewayConfig
+
+
+def test_load_transcript_returns_db_messages_when_no_jsonl(tmp_path):
+    """Reading a transcript must work from SQLite alone — no JSONL fallback needed."""
+    config = GatewayConfig()
+    store = SessionStore(sessions_dir=tmp_path, config=config)
+
+    sid = "test-session-db-only"
+    store._db.create_session(session_id=sid, source="test")
+    store.append_to_transcript(sid, {"role": "user", "content": "hello", "timestamp": 1.0})
+    store.append_to_transcript(sid, {"role": "assistant", "content": "world", "timestamp": 2.0})
+
+    # Delete any JSONL that the current dual-writer left behind
+    jsonl_path = tmp_path / f"{sid}.jsonl"
+    if jsonl_path.exists():
+        jsonl_path.unlink()
+
+    history = store.load_transcript(sid)
+    assert len(history) == 2
+    assert history[0]["content"] == "hello"
+    assert history[1]["content"] == "world"