polac24

protocol DefaultProvidable {
   static var defaultValue: Self {get}
}
extension Bool: DefaultProvidable {
    static let defaultValue = false
}
extension Optional: DefaultProvidable {
    static var defaultValue: Optional<Wrapped> {return nil}
}
...

polac24

class DatabaseStub: Database {    
  lazy var addUserAction = niceStub(of: addUser, thatReturns: true)  
  func addUser(name: String) -> Bool {     
    return addUserAction(name)    
  }
}
func testAddingUser_savesToDatabase () {
  // Act
  database.addUser(name: "user1") // ✅, doesn't crash
  ...

polac24

func niceStub<I,O>(of: (I) -> (O), thatReturns: O) -> (I) -> (O){
  return { _ in thatReturns }
}

polac24

// compareAction: ((Int,Int)) -> CompareResult
lazy var compareAction = stub(of: compare) 
func compare(_ element1:Int, _ element2:Int) -> CompareResult {
  return compareAction((element1, element2))
}

polac24

func stub<I,O>(of: (I) -> (O)) -> (I) -> (O){
  return nil!
}

polac24

func testAddingUser_savesToDatabase () {
  // Arrange
  var addedUser: String?
  database.addUserAction = { name in
    addedUser = name
    return false
  }
  // Act
  ...
  // Assert

polac24

// helper global function
func stub<T>(of v: T) -> T {    
  return nil!
}
protocol Database {
  func addUser(name: String) -> Bool
}
class DatabaseStub: Database {    
  lazy var addUserAction = stub(of: addUser) // (String) -> Bool
  func addUser(name: String) -> Bool {     

polac24

## Counting code coverage on a subset of files

# "Spies" is a regex in the example
xcrun xccov view --files-for-target StubKit.framework  action.xccovreport  | awk '/Spies/{print $5}' | awk '-F[/()]' '{covered += $2; all += $3} END {print covered/all*100}'

polac24

let RFC3339DateFormatter = with(DateFormatter()) {
    $0.locale = Locale(identifier: "en_US_POSIX")
    $0.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
    $0.timeZone = TimeZone(secondsFromGMT: 0)
}

polac24

func testCallbackIsNotCalledAfterCancel() {
    // Arrange
    let sut = MasterClass()
    // Act
    let tokenMarker = weaklyScoped(NSObject()) { marker in
        sut.start {
            // keep a strong reference to a marker
            _ = marker
        }
        // cancel should clear start's completion