"Test Notification Email Address" feature in BPM Administration

The business is interested in testing the Purchase Order (PO) workflow.

To address this, we suggested utilizing the "Test Notification Email Address" feature in BPM Administration. However, we would like clarification on whether enabling this notification feature will effectively handle this task and if it will also apply to email notifications triggered long back(before we enabled this feature) and pending in queue. We are particularly concerned that it may not address notifications that are already pending.

Please suggest.