iOS Dependecy Injection Swinject Ricardo respose

order-testing-example-1.swift

struct Order {
    var itemPrices: [Int]
}

protocol OrderValidator {
    func hasMinimumSpend(order: Order) -> Bool
}

class OrderViewModel {
    
    // add callback closure for state update
    var didUpdate: (() -> ())?
    
    var isPayButtonEnabled: Bool {
        get {
            return self.validator.hasMinimumSpend(order: self.order)
        }
    }
    
    // Instance state
    
    private var order: Order = Order(itemPrices: [])
    
    // Instance dependency
    
    private let validator: OrderValidator
    
    init(validator: OrderValidator) {
        self.validator = validator
    }
    
    func add(itemPriced: Int) {
        self.order.itemPrices.append(itemPriced)
        self.didUpdate?()
    }
}