How to Fix iOS StoreKit Testing Issues — In-App Purchases Not Working

In this tutorial, you'll learn about How to Fix iOS StoreKit Testing Issues. We cover key concepts, practical examples, and best practices.

The Problem

In-app purchases are not working:

SKProductsRequest returns no products.

or:

Payment queue does not process transactions.

Quick Fix

Step 1: Configure products in App Store Connect

App Store Connect > My Apps > Features > In-App Purchases > Create

Ensure the product ID matches your code exactly.

Step 2: Create a products request

WRONG — missing product identifiers:

let request = SKProductsRequest(productIdentifiers: [])

RIGHT:

let productIdentifiers: Set<String> = ["com.example.app.premium"]
let request = SKProductsRequest(productIdentifiers: productIdentifiers)
request.delegate = self
request.start()

Step 3: Handle the products response

func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
    if response.products.isEmpty {
        print("No products found. Invalid product identifiers: \(response.invalidProductIdentifiers)")
    }
    for product in response.products {
        print("Product: \(product.localizedTitle) - \(product.price)")
    }
}

Step 4: Add the payment queue observer

SKPaymentQueue.default().add(self)

Step 5: Handle transactions

func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
    for transaction in transactions {
        switch transaction.transactionState {
        case .purchased:
            SKPaymentQueue.default().finishTransaction(transaction)
        case .failed:
            if let error = transaction.error as? SKError {
                print("Purchase failed: \(error.code)")
            }
            SKPaymentQueue.default().finishTransaction(transaction)
        case .restored:
            SKPaymentQueue.default().finishTransaction(transaction)
        default:
            break
        }
    }
}

Step 6: Use StoreKit Test in Xcode 14+

Product > Scheme > Edit Scheme > Options > StoreKit Configuration > Select a configuration file

Create a .storekit file:

File > New > File > StoreKit Configuration File

Prevention

• Register products in App Store Connect before coding.
• Test with StoreKit Test configuration files.
• Handle all transaction states including .failed and .restored.

Common Mistakes with storekit testing

1. Mixing let bindings with <- bindings in do notation, producing type errors
2. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
3. Non-exhaustive pattern matches that compile with warnings then crash at runtime

These mistakes appear frequently in real-world IOS code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ