SwiftUI Preview SKProduct with introductoryPrice

Question

I am trying to mock an SKProduct so I'm able to view it in the preview canvas in SwiftUI.

I have been able to create a dummy SKProduct with a convenience init inside SKProduct...

//Mock Product
convenience init(identifier: String, price: String, priceLocale: Locale) {
    self.init()
    self.setValue(identifier, forKey: "productIdentifier")
    self.setValue(NSDecimalNumber(string: price), forKey: "price")
    self.setValue(priceLocale, forKey: "priceLocale")
}

But I can't figure out how to mock introductoryPrice data. I need the subscriptionPeriod numberOfUnits and subscriptionPeriod unit

I'm not sure what keys to write to.

Any thoughts?

Answer 1

They are open classes so the solution is just to use inheritance, like in below demo.

So you can construct and set up your MockSK* entities as you with and pass everywhere, where real SK* instances expected.

import StoreKit

class MockSKProductSubscriptionPeriod: SKProductSubscriptionPeriod {
    private let _numberOfUnits: Int
    private let _unit: SKProduct.PeriodUnit

    init(numberOfUnits: Int = 1, unit: SKProduct.PeriodUnit = .year) {
        _numberOfUnits = numberOfUnits
        _unit = unit
    }

    override var numberOfUnits: Int {
        self._numberOfUnits
    }

    override var unit: SKProduct.PeriodUnit {
        self._unit
    }
}

class MockSKProduct: SKProduct {
    private var _subscriptionPeriod: SKProductSubscriptionPeriod

    init(subscriptionPeriod: SKProductSubscriptionPeriod = MockSKProductSubscriptionPeriod()) {
        _subscriptionPeriod = subscriptionPeriod
    }

    override var subscriptionPeriod: SKProductSubscriptionPeriod? {
        get {
            _subscriptionPeriod
        }
    }
}