fix: improve test isolation and configuration

- Use in-memory SQLite for tests to prevent conflicts
- Add try/finally for robust test cleanup
- Make database URL configurable via env var
- Make CORS origins configurable via env var
- Make SQL echo configurable via env var

backend/app/database.py

@@ -1,9 +1,10 @@
+import os
 from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
 from sqlalchemy.orm import declarative_base
 
-DATABASE_URL = "sqlite+aiosqlite:///./backup_tool.db"
+DATABASE_URL = os.environ.get("DATABASE_URL", "sqlite+aiosqlite:///./backup_tool.db")
 
-engine = create_async_engine(DATABASE_URL, echo=True)
+engine = create_async_engine(DATABASE_URL, echo=os.environ.get("SQL_ECHO", "false").lower() == "true")
 AsyncSessionLocal = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
 
 Base = declarative_base()

backend/app/main.py

@@ -1,3 +1,4 @@
+import os
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 from contextlib import asynccontextmanager
@@ -18,7 +19,7 @@ app = FastAPI(
 
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=["http://localhost:3000"],
+    allow_origins=os.environ.get("CORS_ORIGINS", "http://localhost:3000").split(","),
     allow_credentials=True,
     allow_methods=["*"],
     allow_headers=["*"],

backend/tests/conftest.py

@@ -5,21 +5,22 @@ from app.database import Base, get_db
 from app.main import app
 from httpx import AsyncClient
 
-TEST_DATABASE_URL = "sqlite+aiosqlite:///./test.db"
+TEST_DATABASE_URL = "sqlite+aiosqlite:///:memory:"
 
 @pytest_asyncio.fixture
 async def db():
     engine = create_async_engine(TEST_DATABASE_URL, echo=False)
-    async with engine.begin() as conn:
-        await conn.run_sync(Base.metadata.create_all)
-    
-    async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
-    async with async_session() as session:
-        yield session
-    
-    async with engine.begin() as conn:
-        await conn.run_sync(Base.metadata.drop_all)
-    await engine.dispose()
+    try:
+        async with engine.begin() as conn:
+            await conn.run_sync(Base.metadata.create_all)
+        
+        async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
+        async with async_session() as session:
+            yield session
+    finally:
+        async with engine.begin() as conn:
+            await conn.run_sync(Base.metadata.drop_all)
+        await engine.dispose()
 
 @pytest_asyncio.fixture
 async def client(db):