Hi @Reynaldy
Happy to offer more insight on this!
Yes, essentially, you can’t Preview or "Test" an Email because no one has triggered this event or done the action necessary to populate the data. Unfortunately, you can’t preview the email without data, suggesting you buy your own product and later cancel the order is the most efficient way to give you the data you need to preview the email at the moment.
You cannot just pull random data, it has to come from an event. However, you will not have need to repeat this action multiple times to preview the email. In the future when you have more customers who are buying product and receiving these emails, you can easily preview the emails as data will be flowing in.
Thanks for sharing your question with us!
-Taylor