Test cards:
4242424242424242    Succeeds and immediately processes the payment.
4000002500003155    Requires authentication for the initial purchase, but succeeds for subsequent payments (including off-session ones) as long as the card is setup with setup_future_usage.
4000002760003184    Requires authentication for the initial purchase, and fails for subsequent payments (including off-session ones) with an authentication_required decline code.
4000008260003178    Requires authentication for the initial purchase, but fails for subsequent payments (including off-session ones) with an insufficient_funds decline code.
4000000000009995    Always fails (including the initial purchase) with a decline code of insufficient_funds.