For SPEI payment method there aren’t any test data available, but you can see how it works with the payment flow given below.
SPEI Payment Flow
The customer enters his Email Address, Name and CURP/RFC/IFE.
Please note that for Mexico the Customer Social Security Number parameter consists of CURP/RFC/IFE. For more information about the CURP/RFC/IFE please click here.
The customer receives the printable payment details in order to complete the payment.
Upon completion of the payment flow the customer is redirected back to your ReturnURL.