danielCarlosCE

    private func isCodeInLimitBounds(codeReadable: AVMetadataMachineReadableCodeObject) -> Bool {

        if  let videoLayer = previewLayer as? AVCaptureVideoPreviewLayer,
            let transformedObj = videoLayer.transformedMetadataObject(for: codeReadable),
            let limitBounds = limitBounds {
            return limitBounds.contains(transformedObj.bounds)
        }
        //ignore 'failure' above
        return true
    }

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

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

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

danielCarlosCE

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