You can test with your own email address. Here are some basic steps.
1. Register yourself as a favorite customer by tapping on "Enrolled Customers"
2. Search and find your name / email address and click on edit. In the popup screen, check the "Favorite" box.
3. Verify you are now a favorite customer by tapping on the "Favorite customers" link on the Navigation bar
4. Set up your Customer Reward, and select the target as "Favorite Customers". And, you will receive the reward as your customers would.