viewCode-test-viewControllerTests.swift

final class ExampleViewControllerTests: XCTestCase {
    private lazy var viewController: ExampleViewController = {
        let viewController = ExampleViewController(customView: self.mockCustomView,
                                                   presenter: self.mockPresenter)
    }()

    private let mockCustomView = MockExampleCustomView()
    private let mockPresenter = MockExamplePresenter()

    func testViewWillAppear() {
        viewController.viewWillAppear(false)
        XCTAssertTrue(mockPresenter.didCallFetchData)
        XCTAssertTrue(mockCustomView.didCallRenderLoading)
    }

    func testDidFetchData() {
        viewController.didFetch(data: "mock_data")
        XCTAssertTrue(mockCustomView.didCallRenderData)
        XCTAssertTrue(mockCustomView.dataToBeRender == "mock_data")
    }
}