Swift：测试Segue是否存在,有正确的目的地并改变正确的东西

我是快速测试的新手,目前我想尝试四项测试.我有一个从ViewController到另一个的segue(searchingForViewController).对于这个segue,我想测试这4件事：

>是否存在标识符为“searchSegue”的segue？
>是否会调用segue然后点击按钮搜索？
> Seogle的目的地是SearchedForViewController
> Segue将SearchedForVC的变量“passString”更改为“garten”吗？

我在Main.storyboard中的segue如下所示：

我的segue代码如下(工作,但未来我只想知道如何测试)：

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "searchSegue" {
            guard let controller = segue.destination as? SearchedForViewController 
        else {
                return
            }
                controller.passedString = "garten"
        }
    }

目前我的测试类就像是空的,看起来像这样(只是加载视图)：

class ViewControllerTests: XCTestCase {

    var vc: ViewController!

    override func setUp() {
        super.setUp()

        let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
        vc = storyboard.instantiateViewController(withIdentifier: "test") as! ViewController
        let _ = vc.view
    }

    func testSegueShouldExist() {
        let identifiers = getSegues(ofViewController: vc)
        XCTAssertEqual(identifiers.count, 1, "Segue count should equal one.")
        XCTAssertTrue(identifiers.contains("searchSegue"), "Segue searchSegue should exist.") 
    }

    func testSegueActionsThenPushSearchButton() {
        // code here  
    }

    func testSegueDirectsToSearchedForViewController() {
        // code here  
    }

    func testSeguePassedGartenAsValueToSearchedForVC() {
        // call prepare and test after? 
    }
}

编辑我发现了如何实现segueShouldExist.我添加了代码.它调用辅助函数：

func getSegues(ofViewController viewController: UIViewController) -> [String] {
        let identifiers = (viewController.value(forKey: "storyboardSegueTemplates") as? [AnyObject])?.flatMap({ $0.value(forKey: "identifier") as? String }) ?? []
        return identifiers
    }

要实现这一点,您需要重新调整代码.

# ViewControllerTests.swift
var capturedSegue: UIStoryboardSegue?

extension ViewController {
    override open func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        prepareSearchForVC(with: segue)
        capturedSegue = segue
    }
}

class ViewControllerTests: XCTestCase {

    var vc: ViewController!

    override func setUp() {
        super.setUp()

        let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
        vc = storyboard.instantiateInitialViewController() as! ViewController
        vc.loadViewIfNeeded()
    }

    func testSegueShouldExist() {
        let identifiers = getSegues(ofViewController: vc)
        XCTAssertEqual(identifiers.count, 1, "Segue count should equal one.")
        XCTAssertTrue(identifiers.contains("searchSegue"), "Segue searchSegue should exist.")
    }

    func testSegueActionsThenPushSearchButton() {
        // Can programmatically send actions to UIControl classes
        vc.searchButton.sendActions(for: .touchUpInside)

        // Just makes sure any segue was called
        // since there is only one in this case there's no need to be more specific
        XCTAssertNotNil(capturedSegue) 
    }

    func testSegueDirectsToSearchedForViewController() {
        vc.performSegue(withIdentifier: "searchSegue", sender: nil)

        // Attempts to cast the captured segue
        let destination = capturedSegue?.destination as? SearchedForVC

        XCTAssertNotNil(destination,
                        "Destination should be searched for controller")
    }

    func testSeguePassedGartenAsValueToSearchedForVC() {
        vc.performSegue(withIdentifier: "searchSegue", sender: nil)

        let destination = capturedSegue?.destination as? SearchedForVC

        XCTAssertEqual(destination?.passedString, "garten")
    }

    func getSegues(ofViewController viewController: UIViewController) -> [String] {
        let identifiers = (viewController.value(forKey: "storyboardSegueTemplates") as? [AnyObject])?.flatMap({ $0.value(forKey: "identifier") as? String }) ?? []
        return identifiers
    }
}

这项工作的原因是改变了ViewController中的prepare(for：,sender :)方法：

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "searchSegue" {
        guard let controller = segue.destination as? SearchedForViewController 
    else {
            return
        }
            controller.passedString = "garten"
    }
}

至：

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    prepareSearchForVC(with: segue)
}

func prepareSearchForVC(with segue: UIStoryboardSegue) {
    if segue.identifier == "searchSegue" {
        guard let controller = segue.destination as? SearchedForVC
            else {
                return
        }
        controller.passedString = "garten"
    }
}

希望有所帮助.