This recipe allows you to specify your own customers_id from your dummy account for safely testing a payment module while keeping it hidden from all other users. While the test is under progress, other users can freely access all other payment modules. This hack is highly adaptable as you will be using the same code for whichever payment module you require hidden. The define for you as a Master Customer is done in the main configuration area, and only a few lines of code need to be added to hide for the time being the modules you would like to test.
Your screen in Administration | Configuration | Hide Payment Modules will look like the following when you are planning to hide a payment module (this recipe uses PSiGate) while you are running your tests.
(PSiGate is a great Credit Card Gateway for testing as it doesn't require you to sign up for a merchant account for testing purposes.)
In this scenario, the standard osCommerce Credit Card...