For MTCPay payment method there aren’t any test data available, but you can see how it works with the payment flow given below.
MTCPay Payment Flow
The Customer enters his email address.
The Customer logs in his MTCPay account with his username and password. He also has to enter the code given in the security box before proceeding with the payment.
The customer sees the payment summary and he completes the transaction by clicking on the Pay button.
Upon completion of the payment flow the customer is redirected back to your ReturnURL.