TOPIC: Test Payments

Am I missing something (probably) - how do you test payments? I've set up a set of payment options to be in test mode but I get errors on both auth.net and paypal.

I'd like to try all the payment options out before going live. Do I need to also enter the auth.net API key? I've entered the PayPal email address but PayPal rejects it.

Please tell me what I'm missing...

Best,
Mark