Sweet and concise stubbing and dummying in Swift

sweet-doubles.swift

struct Money {
  let currencyCode: String
  let cents:        Int
}

struct Cost {
  let price: Money
  let fee:   Money
  let total: Money
}

// In a production code you would use these structs as usual:
let cost = Cost(price: Money(currencyCode: "RUB", cents: 75000),
                fee:   Money(currencyCode: "RUB", cents: 7500),
                total: Money(currencyCode: "RUB", cents: 82500))

// But in your tests code you could make extensions that produce dummies and stubs
extension Money {
  static func dummy() -> Money {
    return Money(currencyCode: "RUB", cents: 0)
  }
  
  static func stub(cents cents: Int) -> Money {
    return Money(currencyCode: "RUB", cents: cents)
  }
}

let costForTesting = Cost(price: .stub(cents: 1), fee: .dummy(), total: .stub(cents: 1))

Cool!

Just one comment, the last parameter must be total, not price ;)

let costForTesting = Cost(price: .stub(cents: 1), fee: .dummy(), total: .stub(cents: 1))

@gn0meavp Thanks, man. Fixed!