It's extremely common. You want to know that objects/rows from one test don't bleed into another by accident. It allows you to write more strict and simpler ass

It's extremely common. You want to know that objects/rows from one test don't bleed into another by accident. It allows you to write more strict and simpler assetions - like "there's one active user in the database" after a few changes, rather than "this specific user is in the database and active and those other ones are not anymore". Leaking information between test runs can actually make things pass by accident.