CakePattern.swift

//: Playground - noun: a place where people can play

import UIKit
import XCTest

struct Product {
    var name: String
    var price : Double
}

protocol ProductsRepository {
    
    func fetchProducts() -> [Product]
}

struct ProductsRepositoryImplementation : ProductsRepository {
    func fetchProducts() -> [Product] {
        
        return [Product(name: "Addidas Sneakers", price: 1000.0), Product(name: "Nike Sneakers", price: 1000.0)]
    }
}

protocol ProductsRepositoryInjectable {
    var products : ProductsRepository {get}
}

extension ProductsRepositoryInjectable {
    
    var products : ProductsRepository {
        return InjectableMap.resolve()
    }
    
}

public class InjectableMap {
    
    private static  var  mapper : ProductsRepository = ProductsRepositoryImplementation()
    
    static func resolve() -> ProductsRepository {
        return mapper
    }
    
    static func set(_ mapper : ProductsRepository) {
        self.mapper = mapper
    }
    
    static func reset(){
        self.mapper = ProductsRepositoryImplementation()
    }
    
}

struct MockProductsRepositoryImplementation : ProductsRepository {
    func fetchProducts() -> [Product] {
        
        return [Product(name: "Mock Addidas Sneakers", price: 500), Product(name: "Nike Sneakers", price: 200)]
    }
}



struct ProductViewModel: ProductsRepositoryInjectable {
   
    init() {
        self.products.fetchProducts().forEach {
            print("This \($0.name) costs R\($0.price)")
        }
    }
}

ProductViewModel()

func testGivenAProductTheProductsPriceWillBeFiveHundred() {
    
    InjectableMap.set(MockProductsRepositoryImplementation())
    let expectedPrice = 500.0
    let viewModel = ProductViewModel()
    XCTAssertTrue(viewModel.products.fetchProducts().first?.price == expectedPrice)
    
}

The method named 'set' , will it be okay if one names it 'inject'?