app稳定性测试-iOS篇

稳定性测试：测试应用程序在长时间运行过程中是否存在内存泄漏、崩溃等问题，以确保应用程序具有较高的稳定性和可靠性。

对于安卓端，官方提供了很好的稳定性测试工具：monkey。相比较而言，iOS则没有，而且当前网络上似乎也没有很好的第三方工具可以使用，因此只能自己写了。

我们要开发的iOS稳定性测试程序，应该至少包含以下内容：

持续随机触发UI事件
崩溃重启，测试不中断
日志记录

首先我们确定以上设想的可行性，然后再制定实施方案。在iOS原生开发语言swift和object-C中提供了可进行单元测试和UI测试的XCTest框架，而同样可进行移动端UI测试的第三方框架还有Appium等，但相比较第三方的开源框架，原生的XCTest框架性能更好且更稳定，因此这里我们选择基于swift语言和XCTest框架来开发。XCTest框架提供了非常全面的启动App和UI操作相关的API接口，因此1、2两点完全可以实现，当然第三点的日志记录的实现也同样不会有什么问题。接下来就是具体实施了。

首先，我们创建一个用来执行测试的主类：StabilityTestRunner，然后再编写代码去实现以上三点。

一、持续随机触发UI事件

让我们拆分一下，随机触发UI事件，实际上包含两部分：随机UI元素和随机的UI操作。那么：

随机生成UI元素：

func randomElement(of types: [ElementType]) -> XCUIElement? {
        var allElement:[XCUIElement] = []
        for type in types {
            if !self.exists{
                break
            }
            var elements: [XCUIElement]
            if self.alerts.count > 0 {
                elements = self.alerts.descendants(matching: type).allElementsBoundByIndex
            }else {
                elements = self.descendants(matching: type).allElementsBoundByIndex
            }
            let filteredElements = elements.filter { element in
                if !element.exists {
                    return false
                }
                if !element.isHittable || !element.isEnabled {
                    return false // Filter out non clickable and blocked elements.
                }
                return true
            }
            allElement.append(contentsOf: filteredElements)
        }
        
        return allElement.randomElement()
    }

随机生成UI操作：

/**
     Random execution of the given UI operation.
     - parameter element: Page Elements.
     - parameter actions: Dictionary objects containing different UI operations.
     */
    private func performRandomAction(on element: XCUIElement, actions: [String: (XCUIElement) -> ()]) {
        let keys = Array(actions.keys)
        let randomIndex = Int.random(in: 0..<keys.count)
        let randomKey = keys[randomIndex]
        let action = actions[randomKey]
        
        if action == nil {
            return
        }
        
        if !element.exists {
            return
        }
        
        if !element.isHittable {
            return
        }
        Utils.log("step\(currentStep): \(randomKey) \(element.description)")
        action!(element)
    }

二、持续测试和崩溃重启

while !isTestingComplete{
            // Randomly select page elements.
            let element = app.randomElement(of: elementType)
            if element != nil {
                currentStep += 1
                takeScreenshot(element: element!)
                performRandomAction(on: element!, actions: actions) // Perform random UI operations.
                XCTWaiter().wait(for: [XCTNSPredicateExpectation(predicate: NSPredicate(format: "self == %d", XCUIApplication.State.runningForeground.rawValue), object: app)], timeout: stepInterval)
                if app.state != .runningForeground {
                    if app.state == .notRunning || app.state == .unknown {
                        Utils.saveImagesToFiles(images: screenshotData)
                        Utils.saveImagesToFiles(images: screenshotOfElementData, name: "screenshot_element")
                        Utils.log("The app crashed. The screenshot before the crash has been saved in the screenshot folder.")
                    }
                    app.activate()
                    
                }
            }
        }

三、日志记录

记录截图并标记UI元素：

private func takeScreenshot(element: XCUIElement) {
        let screenshot = app.windows.firstMatch.screenshot().image
        if screenshotData.count == 3 {
            let minKey = screenshotData.keys.sorted().first!
            screenshotData.removeValue(forKey: minKey)
        }
        let screenshotWithRect = Utils.drawRectOnImage(image: screenshot, rect: element.frame)
        screenshotData[currentStep] = screenshotWithRect.pngData()
        let screenshotOfElement = element.screenshot().pngRepresentation
        if screenshotOfElementData.count == 3 {
            let minKey = screenshotOfElementData.keys.sorted().first!
            screenshotOfElementData.removeValue(forKey: minKey)
        }
        screenshotOfElementData[currentStep] = screenshotOfElement
    }

通过文本日志记录测试执行过程：

static func log(_ message: String) {
        print(message)
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
        let dateString = dateFormatter.string(from: Date())
        let fileManager = FileManager.default
        do {
            try fileManager.createDirectory(atPath: logSavingPath, withIntermediateDirectories: true, attributes: nil)
        } catch {
            print("Error creating images directory: \(error)")
        }
        var fileURL: URL
        if #available(iOS 16.0, *) {
            fileURL = URL.init(filePath: logSavingPath).appendingPathComponent("log.txt")
        } else {
            fileURL = URL.init(fileURLWithPath: logSavingPath).appendingPathComponent("log.txt")
        }
        do {
            try "\(dateString) \(message)".appendLineToURL(fileURL: fileURL)
        } catch {
            print("Error writing to log file: \(error)")
        }

日志导出：

// To add the log files to the test results file, you can view it on your Mac. The test results file path: /User/Library/Developer/Xcode/DerivedData/AppStability-*/Logs.
        let zipFile = "\(NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0])/Logs.zip"
        let attachment = XCTAttachment(contentsOfFile: URL(fileURLWithPath: zipFile))
        attachment.name = "Logs"
        attachment.lifetime = .keepAlways
        // Add the "Logs.zip" file to the end of test result file.
        add(attachment)
        Utils.log("The logs for test steps has been added to the end of test result file at /User/Library/Developer/Xcode/DerivedData/AppStability-*/Logs")

注：以上代码只是主体实现，了解相关细节可通过GitHub或Gitee查阅完整代码。