Stabilize test imports with explicit project root path

tests/test_api.py

@@ -1,12 +1,18 @@
 import importlib
 import os
+import sys
 import time
+from pathlib import Path
 from typing import Iterator
 
 import pymysql
 import pytest
 from fastapi.testclient import TestClient
 
+PROJECT_ROOT = Path(__file__).resolve().parents[1]
+if str(PROJECT_ROOT) not in sys.path:
+    sys.path.insert(0, str(PROJECT_ROOT))
+
 
 def wait_for_db(host: str, port: int, user: str, password: str, timeout_seconds: int = 60) -> None:
     deadline = time.time() + timeout_seconds