Add unit tests for store

**Feature request**
It would be great to have logging for services.

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

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

First resolve the scope mismatch between the title's request for unit tests for the store and the body’s request for service logging. Then locate the store implementation, configuration entry points, and existing tests; done should include coverage for the agreed behavior and verification that enable_logging defaults to false if that remains in scope.

Written by the indexing model from the issue text.