Add unit tests for components

**Feature request**
It would be great to have notifications for auth.

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

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

Start by locating the configuration entry point and the auth-related components. Clarify how enable_notifications should affect authentication notifications and reconcile that with the title's request for unit tests. Done means the option has a defined default and behavior, with tests covering the agreed notification cases.

Written by the indexing model from the issue text.