No. You don't need to delete test registrations, and we recommend you don't.

While your event's status is Testing, every registration is marked as a test registration. When you change the status to Live under Plan > Event Setup > Details, those test registrations are taken out of your live registration lists. You can still find them in the Registrations to Review section at the bottom of the Event Dashboard.

FAQ

Real people registered while the event was still in Testing. How do I keep their registrations?

After you set the event to Live, scroll to the Registrations to Review section at the bottom of the Event Dashboard. Click the number of Test Registrations, select the registrations you want to keep, choose Mark as Live from the mass action list, and click Go.

What else is in Registrations to Review?

It's where you find registrations that need a second look, such as test registrations and possible duplicates. To look for specific people or details, a report is usually easier.

Can I avoid this next time?

Share the registration link only after the event is set to Live.