diff --git a/backend/src/modules/groups/services/groups.service.spec.ts b/backend/src/modules/groups/services/groups.service.spec.ts
index 424396f..d30d80d 100644
--- a/backend/src/modules/groups/services/groups.service.spec.ts
+++ b/backend/src/modules/groups/services/groups.service.spec.ts
@@ -161,7 +161,16 @@ describe('GroupsService', () => {
       const id = 'nonexistent';
       mockDb.select.mockImplementationOnce(() => mockDbOperations);
       mockDbOperations.from.mockImplementationOnce(() => mockDbOperations);
-      mockDbOperations.where.mockImplementationOnce(() => [undefined]);
+      mockDbOperations.where.mockImplementationOnce(() => []);
+
+      await expect(service.findById(id)).rejects.toThrow(NotFoundException);
+    });
+
+    it('should throw NotFoundException if there is a database error', async () => {
+      const id = 'invalid-id';
+      mockDb.select.mockImplementationOnce(() => {
+        throw new Error('Database error');
+      });
 
       await expect(service.findById(id)).rejects.toThrow(NotFoundException);
     });