feat(tests): scaffold + integration smoke tests (config, db, models, pipeline)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/scaffold/test_db.py

@@ -0,0 +1,35 @@
+"""Smoke tests for codex.db — get_conn and apply_schema."""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock, patch
+
+
+def test_get_conn_context_manager() -> None:
+    """get_conn() yields a context manager that calls psycopg.connect and cleans up."""
+    from codex.db import get_conn
+
+    mock_conn = MagicMock()
+    mock_connect = MagicMock()
+    # psycopg.connect is itself used as a context manager inside get_conn
+    mock_connect.return_value.__enter__ = MagicMock(return_value=mock_conn)
+    mock_connect.return_value.__exit__ = MagicMock(return_value=False)
+
+    with patch("codex.db.psycopg.connect", mock_connect), get_conn() as conn:
+        assert conn is mock_conn
+
+    mock_connect.assert_called_once()
+
+
+def test_apply_schema_executes_sql() -> None:
+    """apply_schema(conn) calls conn.execute and conn.commit."""
+    from codex.db import apply_schema
+
+    mock_conn = MagicMock()
+
+    # Provide a fake schema.sql so Path.read_text succeeds
+    with patch("codex.db.Path.read_text", return_value="CREATE TABLE IF NOT EXISTS test ();"):
+        apply_schema(mock_conn)
+
+    mock_conn.execute.assert_called_once()
+    mock_conn.commit.assert_called_once()