How to test in-app billing in App-Store Sandbox iOS?

Question

I have setup an App in Apple App Store as a free app. Not yet submitted. I added an in-app purchase as auto-renewable subscription

Trying to implement/test this using https://github.com/jamesmontemagno/InAppBillingPlugin within my app.

This returns true-

await billing.ConnectAsync(true);

This then breaks-

var prodInfo = await billing.GetProductInfoAsync(ItemType.Subscription, prodIds);
UNKNOWN ERROR returned.

My only thought is that the prodId for the in-app purchase is not available (yet).

QUESTION: Does the app have to have been submitted for the target in-app purchase to be exposed in the app store for testing with a sandbox appleId account?

• Lindsay: Moving on..: The in-app-purchase is now returned from the App Store, however, in the store it is set as Auto-Renewable. When returned from the PurchaseAsync() method, the AutoRenewable flag is false. Also, I added an App Store Promotion for the one and only IAP but the PurchaseAsync() method errors with UnknownError using the IAP Promo product ID. In the promo details in the app store, I see this: "These in-app purchases can’t be promoted on the App Store because your latest approved binary doesn’t include the SKPaymentTransactionObserver method." Any advice on those two issues?
• nevermore: You can update these information in the question. And you set Auto-Renewable in the store while the AutoRenewable flag returns false in the code, this may caused by the delay of async information. You can try it later. For the second issue, you can search in google and there are different solutions.

Answer 1

Your app's first in-app purchase must be approved by Apple in order to exist at all (i.e. even to be available for testing). Yours, presumably, has not been approved.

You can submit the app build and the in-app purchase together for approval. However, my experience is that it is actually simpler to submit the app build without the in-app purchase, get it approved, and then submit the in-app purchase for approval.

Note that your app must visibly provide the correct interface for letting the user interact with the purchase. You should point out to the reviewers where this interface is to be found.

• Luke Vo: Is this still the case? I have to submit an app with IAP and get approved in order to... test it? How do you know it works in the first place?