danielCarlosCE

override func setUp() {
    super.setUp()
    let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
    readerVC = mainStoryboard.instantiateViewController(withIdentifier: "ReaderViewController") as! ReaderViewController

    readerVC.dataSource = MockDataSource()
    readerVC.codeReader = mockReader
    
    //force the life cycle to be called
    let window = UIApplication.shared.delegate!.window!

danielCarlosCE

class ReaderViewController: UIViewController {

    @IBOutlet weak var videoPreview: UIView!
    private var videoLayer: CALayer!
    
    var codeReader: CodeReader!

    override func viewDidLoad() {
        videoLayer = codeReader.videoPreview
        videoPreview.layer.addSublayer(videoLayer)

danielCarlosCE

extension AVCodeReader: CodeReader {
    func startReading(completion: @escaping (String) -> Void) {
        self.didRead = completion
        captureSession?.startRunning()
    }
    func stopReading() {
        captureSession?.stopRunning()
    }
}

danielCarlosCE

extension AVCodeReader: AVCaptureMetadataOutputObjectsDelegate {
    func metadataOutput(_ captureOutput: AVCaptureMetadataOutput,
                        didOutput metadataObjects: [AVMetadataObject],
                        from connection: AVCaptureConnection) {
        guard let readableCode = metadataObjects.first as? AVMetadataMachineReadableCodeObject,
              let code = readableCode.stringValue else {
             return
        }

        //Vibrate the phone

danielCarlosCE

override init() {
  super.init()

  //Make sure the device can handle video
  guard let videoDevice = AVCaptureDevice.default(for: .video),
        let deviceInput = try? AVCaptureDeviceInput(device: videoDevice) else {
      return
  }
  
  //session

danielCarlosCE

protocol CodeReader {
  func startReading(completion: @escaping (String) -> Void)
  func stopReading()
  var videoPreview: CALayer {get}
}