How to test payment with credit cards?

Question

Software testing

Good morning everyone.
There is a service that implements a payment mechanism. I want to cover it with tests, including automatic ones. I will test transactions with regular VISA && MasterCard cards. Share the experience of who implemented such scenarios on what, what systems they used, how they conducted transactions in development mode.
I would be very grateful for the manuals and experience from the fields.

Answer 1

I can’t speak for everyone, but when I worked with Stripe, I actively used test cards. They were fine with that.
That is, in billing, they had the opportunity to switch between test / working mode, and if a test card number was sent in test mode, a fake payment was made with the correct answer.
Look, maybe you also have a similar system in the payment aggregator.

Answer 2

No matter how beautiful the architecture around communication with the api is.
All this turns out to be twisted around a banal request to the server to receive a response from it.
All mocks and other solutions are also just beauty over replacement
But the naked truth of debugging ;)
// $data = curl_exec($ch);
$data = join('',file('test.dat'));