Hi! I'm working on subscriptions API on a development store created with the partner dashboard. These type of stores allow only test payment methods and if you try to process a real payment method, then the store's checkout will be blocked.
The problem comes in when you try to renew a subscription trough the subscriptionBillingAttemptCreate: according to the linked example call, this mutation should have a testparameter inside subscriptionBillingAttemptInput that indicates whether to execute the payment in test mode (in order to avoid the checkout block). That seems to not be true: if you check the SubscriptionBillingAttemptInput GraphQL documentation you will find out that the test parameter doesn't exists and if you try to include it in your API call, you will receive this error message: