如何测试 UIAlertController

Question

我正在测试一个提供 UIAlertController 的函数，但测试一直失败。这是函数的样子：

func presentBuyingErrorDialogue() {
  let alert = UIAlertController(
    title: "Warning",
    message: "Error purchasing item, please retry this action. If that doesn't help, try restarting or reinstalling the app.",
    preferredStyle: .alert
  )
  let okButton = UIAlertAction(title: "OK", style: .default)
  alert.addAction(okButton)
  self.present(alert, animated: true, completion: nil)
}

由于此函数位于名为 ShopViewController 的类中，因此我假设测试此函数的正确方法是调用该函数shopViewController.presentBuyingErrorDiaologue()然后使用XCTAssertTrue(shopViewController.presentedViewController is UIAlertController). 但是，当我运行测试时，断言语句失败。测试 UIAlertController 是呈现视图的正确方法是什么？

Answer 1

You should wait that UIAlertController is fully presented before testing its visibility, so you might try to change your test following this way:

import XCTest

class UIAlertControllerTests: XCTestCase {

    func presentBuyingErrorDialogue() {
      let alert = UIAlertController(title: "Warning", message: "Error purchasing item, please retry this action. If that doesn't help, try restarting or reinstalling the app.", preferredStyle: .alert)
      let okButton = UIAlertAction(title: "OK", style: .default)
      alert.addAction(okButton)
      UIApplication.shared.keyWindow?.rootViewController?.present(alert, animated: true, completion: nil)
    }

    func testPresentBuyingErrorDialogue() {
      self.presentBuyingErrorDialogue()
      let expectation = XCTestExpectation(description: "testExample")
      DispatchQueue.main.asyncAfter(deadline: .now() + 1.0, execute: {
        XCTAssertTrue(UIApplication.shared.keyWindow?.rootViewController?.presentedViewController is UIAlertController)
        expectation.fulfill()
      })
      wait(for: [expectation], timeout: 1.5)
   }
}

你可能会UIApplication.shared.keyWindow?.rootViewController随着你的ShopViewController.

Answer 2

1. 将ViewControllerPresentationSpy添加到您的测试目标
2. import ViewControllerPresentationSpy
3. 在测试调用之前实例化 AlertVerifier shopViewController.presentBuyingErrorDialogue()

然后调用它的verify方法：

alertVerifier.verify(
    title: "Warning",
    message: "Error purchasing item, please retry this action. If that doesn't help, try restarting or reinstalling the app.",
    animated: true,
    presentingViewController: shopViewController,
    actions: [
        .default("OK"),
    ]
)

这会检查：

• 出现了一个带有动画的警报。
• 呈现视图控制器是shopViewController.
• 警报标题。
• 警报消息。
• 首选样式是.alert（默认情况下）
• 每个动作的标题和样式。

除了捕获值之外，AlertVerifier 还可以让您轻松执行警报按钮的操作：

func test_alertOKButton() throws {
    shopViewController.presentBuyingErrorDiaologue()

    try alertVerifier.executeAction(forButton: "OK")

    // Test the results here
}

测试不需要任何等待的期望，因此它们非常快。