viewCode-test-viewControllerPresenterDelegate.swift

typealias CustomViewDelegate = UITableViewDelegate & UITableViewDataSource

protocol CustomViewProtocol where Self: UIView {
    func render(data: String)
    func renderLoadingState()
}

final class ExampleViewController: UIViewController {
    private let customView: CustomViewProtocol
    private let presenter: ExamplePresenter

    init(customView: CustomViewProtocol, presenter: ExamplePresenter) {
        self.customView = customView
        self.presenter = presenter
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        // Should test it
        customView.renderLoadingState()
        presenter.fetchData()
    }

    override func loadView() {
        view = customView
    }
}

extension ExampleViewController: PresenterDelegate {
    func didFetch(data: String) {
        // test it
        customView.render(data: data)
    }
}