hack to get $app/stores import working

Author: billyvg

packages/sveltekit/.empty.js

@@ -0,0 +1,2 @@
+// Hack to get $app/stores import working (can't mock it in tests if path is not resolvable).
+// See: https://github.com/vitest-dev/vitest/issues/4630

packages/sveltekit/vite.config.ts

@@ -1,3 +1,6 @@
+import { dirname, resolve } from 'path';
+import { fileURLToPath } from 'url';
+
 import type { UserConfig } from 'vitest';
 
 import baseConfig from '../../vite/vite.config';
@@ -10,5 +13,11 @@ export default {
     ...(baseConfig as UserConfig & { test: any }).test,
     environment: 'jsdom',
     setupFiles: ['./test/vitest.setup.ts'],
+    alias: [
+      {
+        find: '$app/stores',
+        replacement: resolve(fileURLToPath(dirname(import.meta.url)), '/.empty.js'),
+      },
+    ],
   },
 };