# Testing a successful transaction Confirm that your app can make a successful transaction in the sandbox environment by inspecting the transaction. ## Discussion Set a breakpoint in your implementation of the transaction queue observer’s [`paymentQueue(_:updatedTransactions:)`](/documentation/StoreKit/SKPaymentTransactionObserver/paymentQueue(_:updatedTransactions:)) method. Then sign in to the App Store with a Sandbox Apple Account, and make a purchase in your app. Inspect the transaction to verify that its status is [`SKPaymentTransactionState.purchased`](/documentation/StoreKit/SKPaymentTransactionState/purchased). Set a breakpoint at the point in your code where your app stores the purchase, and confirm that your code saves the data in response to a successful purchase. Inspect the user default or iCloud key-value store, to verify that your code correctly records the information. For more information on saving data in response to a successful purchase, see [Persisting a purchase](/documentation/StoreKit/persisting-a-purchase). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)