Once you have successfully added your payment gateway to your Recurly site, you can preform a gateway configuration test to do a basic verification check. You can do this by going back under configuration -> payment gateways (direct link here). Then you can scroll to where you see the desired payment gateway in your list. Then mouse over options and a drop down will appear from there you can select "Test Configuration". This will simply give you a general idea if your gateway is connected correctly.

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Once you are in production and ready to begin collecting payments we suggest you preform a live transactions as a final test to ensure your gateway is up and running. You can create an account in your Recurly site that you can use and add a real credit card number to it. Then create a one time charge and invoice it to test and confirm if the transaction is successful. If successful you can void the transaction so your card isn't actually charged. This will let you confirm your gateway is configured correctly for processing and is correctly connected to Recurly.