chore: restore original directory structure (project under code-review-graph-main/)

code-review-graph-main/tests/fixtures/__tests__/UserService.ts

@@ -0,0 +1,15 @@
+import { describe, it, expect } from 'vitest';
+import { UserRepository, UserService } from '../sample_typescript';
+
+describe('UserService (under __tests__/)', () => {
+  it('constructs a service', () => {
+    const service = new UserService();
+    expect(service).toBeDefined();
+  });
+
+  it('returns undefined for missing user', () => {
+    const service = new UserService();
+    const user = service.getUser(999);
+    expect(user).toBeUndefined();
+  });
+});