diff --git a/packages/backend/test/setup.unit.ts b/packages/backend/test/setup.unit.ts
index b2c9ba0adb..e9adab9d64 100644
--- a/packages/backend/test/setup.unit.ts
+++ b/packages/backend/test/setup.unit.ts
@@ -3,10 +3,8 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { beforeAll } from 'vitest';
-
-beforeAll(() => {
+export default function setup() {
 	// DBはUTC（っぽい）ので、テスト側も合わせておく
 	process.env.TZ = 'UTC';
 	process.env.NODE_ENV = 'test';
-});
+}