Add unit tests for store

**Feature request**
It would be great to have backup for models.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_backup` with default `false`.

No file, test path, or configuration entry point is named. Start by locating the store implementation and its configuration handling, then inspect existing store unit tests; done should cover the requested model-backup behavior and verify that enable_backup defaults to false.

Written by the indexing model from the issue text.