Dependency Injection Playground

import Foundation

struct Bakery {
    func bakeBread() {
        print("make some Bread")
    }
}

struct Kitchen {
    func cookPizza() {

    }

    func makePizza() {
        bakery.bakeBread()
        self.cookPizza()
    }

    var bakery: Bakery

    init(bakery: Bakery) {
        self.bakery = bakery
    }
}

let theBestBakery = Bakery()
let theBestKitchen = Kitchen(bakery: theBestBakery)
theBestKitchen.makePizza()

protocol NetworkAccessible {
    func fetch()
}

struct RealNetwork: NetworkAccessible {
    func fetch() {
        print("I am a real network request!")
    }
}

struct FakeNetwork: NetworkAccessible {
    func fetch() {
        print("I am a fake network request!")
    }
}

struct WebObject {
    var network: NetworkAccessible
    
    init(network: NetworkAccessible) {
        self.network = network
    }
    
    func getData() {
        network.fetch()
    }
}

let realNetwork = RealNetwork()
let fakeNetwork = FakeNetwork()
let realWebObject = WebObject(network: realNetwork)
let fakeWebObject = WebObject(network: fakeNetwork)

realWebObject.getData()
fakeWebObject.getData()