Do I need to add credit to a test account to test in-app billing? (on Google Play)

Do I need to add credit to a test account to test in-app billing?  (on Google Play)

I’m finding I needed to create another google account to test fresh, but then to test purchasing (even though I had the email address listed as a tester) I need to add credit before it will let me purchase.  So I upload my APK to google play but not publish it, then side load this onto my android device.  I have the in-app biling items already published.  So then using my android device to test a “purchase” and a "restore.

Is this correct / normal that you do need to add a credit card to test?