diff --git a/main.py b/main.py
index 5f6ca0d..6cd3637 100644
--- a/main.py
+++ b/main.py
@@ -1,16 +1,21 @@
 from fastapi import FastAPI, HTTPException
 from pydantic import BaseModel, Field
+import os
 import sqlite3
 from datetime import datetime
 from typing import Optional, List
 
 app = FastAPI(title="Shopping List API", version="0.1.0")
 
-DB_PATH = "shopping.db"
+
+def get_db_path():
+    return os.environ.get("DB_PATH", "shopping.db")
+
 
 def get_db():
-    conn = sqlite3.connect(DB_PATH)
+    conn = sqlite3.connect(get_db_path())
     conn.row_factory = sqlite3.Row
+    conn.execute("PRAGMA foreign_keys = ON")
     return conn
 
 def init_db():
@@ -98,7 +103,7 @@ class ListWithItems(ListResponse):
 
 @app.get("/", tags=["meta"])
 def read_root():
-    return {"message": "Shopping List API", "version": "0.1.0"}
+    return {"message": "Shopping List API"}
 
 @app.post("/products", response_model=ProductResponse, status_code=201, tags=["products"])
 def create_product(product: Product):
@@ -188,8 +193,8 @@ def get_list(id: int):
             product_id=row['product_id'],
             quantity=row['quantity'],
             added_at=row['added_at'],
-            product_name=row.get('product_name'),
-            product_sku=row.get('product_sku')
+            product_name=row['product_name'],
+            product_sku=row['product_sku']
         ))
     return ListWithItems(**dict(lst_row), items=items)
 
@@ -238,8 +243,8 @@ def add_item(list_id: int, item: ListItemCreate):
         product_id=row['product_id'],
         quantity=row['quantity'],
         added_at=row['added_at'],
-        product_name=row.get('product_name'),
-        product_sku=row.get('product_sku')
+        product_name=row['product_name'],
+        product_sku=row['product_sku']
     )
 
 @app.patch("/lists/{list_id}/items/{item_id}", tags=["items"])
@@ -293,8 +298,8 @@ def list_items(list_id: int):
             product_id=row['product_id'],
             quantity=row['quantity'],
             added_at=row['added_at'],
-            product_name=row.get('product_name'),
-            product_sku=row.get('product_sku')
+            product_name=row['product_name'],
+            product_sku=row['product_sku']
         )
         for row in rows
     ]
diff --git a/requirements.txt b/requirements.txt
index 0a4249c..cf4b680 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 fastapi
 uvicorn
-sqlalchemy
 pydantic
+pytest
+httpx
diff --git a/test_main.py b/test_main.py
index bb99326..a78ffa7 100644
--- a/test_main.py
+++ b/test_main.py
@@ -1,16 +1,27 @@
+import os
+import tempfile
+
 import pytest
 from fastapi.testclient import TestClient
 from main import app, init_db
-import sqlite3
-import os
 
-client = TestClient(app)
 
 def setup_module(module):
-    # Use an in-memory database for tests
-    os.environ["DB_PATH"] = ":memory:"
+    fd, path = tempfile.mkstemp(suffix=".db")
+    os.close(fd)
+    module.TEST_DB_PATH = path
+    os.environ["DB_PATH"] = path
     init_db()
 
+
+def teardown_module(module):
+    path = getattr(module, "TEST_DB_PATH", None)
+    if path and os.path.exists(path):
+        os.remove(path)
+
+
+client = TestClient(app)
+
 def test_root():
     r = client.get("/")
     assert r.status_code == 200