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ios - Swift 中用于单元测试的静态函数的依赖注入

问题描述

我知道这看起来像是一个常见问题，但是在阅读了 10-15 教程并查看了如何为我的服务类编写测试之后。我无法解决将静态函数移动到协议等的问题。用于依赖注入

我有一个如下图所示的网络层。我所有的函数类（如获取用户、新闻、媒体等）都调用“服务调用者”类，然后如果响应错误；调用“服务错误”类来处理错误，如果没有错误，则解码 JSON。

我的问题是我将服务类作为静态函数调用，如“ServiceCaller.performRequest”，如果出现错误，我还将错误类调用为静态函数，如“ServiceError.handle”。它还调用 URLCache 类来获取请求 url 的路径。我不确定如何让它们在测试类中进行依赖注入和模拟。正如我在教程中发现的那样，我应该这样写；

protocol MyProtocol{
    func myfunction() -> Void
}
class A{
    let testProtocol = MyProtocol!
    init(pro: MyProtocol){
        testProtocol = pro
    }
}

并且可能在测试类的设置功能中；

myMockProtocol = ...
myTestclass = A.init(pro: myMockProtocol)

我的网络层如何工作

但我找不到如何获得像 ServiceCaller.performRequest 或 ServiceError.handle 之类的静态调用..；（问题底部的简化版）

class AppInitService{

static func initAppRequest(_ completion: @escaping (_ appInitRecevingModel: Result<AppInitRecevingModel>) -> Void) {

    let sendingModel = AppInitSendingModel(cmsVersion: AppDefaults.instance.getCMSVersion())
    let route = ServiceRouter(method: .post, path: URLCache.instance.getServiceURL(key: URLKeys.initApp), parameters: (sendingModel.getJSONData()), timeoutSec: 1)
    ServiceCaller.performRequest(route: route) { (result) in
        if let error = result.error{
            if let statusCode = result.response?.statusCode{
                completion(.error(ServiceError.handle(error: error, statusCode: statusCode)))
            }else{
                completion(.error(ServiceError.handle(error: error, statusCode: error._code)))
            }
        }else{
            if let data = result.data{
                do{
                    var responseJson = JSON(data)
                    responseJson["idleTimeoutInMinutes"] = 10
                    let input = try AppInitRecevingModel(data: responseJson.rawData())
                    completion(.success(input))
                }catch let error{
                    completion(.error(ServiceError.handle(error: error, statusCode: -1002)))
                }
            }
        }}
}
 }

我的测试课：

class MyProjectAppInitTests: XCTestCase {

var appInitTest: AppInitService!

override func setUp() {
    super.setUp()
    // Put setup code here. This method is called before the invocation of each test method in the class.
    appInitTest = AppInitService.init()
}

override func tearDown() {
    // Put teardown code here. This method is called after the invocation of each test method in the class.
    appInitTest = nil
    super.tearDown()
}

func testExample() {
    // This is an example of a functional test case.
    // Use XCTAssert and related functions to verify your tests produce the correct results.
    let testParamater = ["string":"test"]
    let route = ServiceRouter(method: .post, path: "/testPath", parameters: testParamater.getJSONData(), timeoutSec: 10)
    appInitTest. //cant call anything in here
}

我寻找的教程单元测试；

https://www.raywenderlich.com/150073/ios-unit-testing-and-ui-testing-tutorial

https://www.swiftbysundell.com/posts/time-traveling-in-swift-unit-tests

https://marcosantadev.com/test-doubles-swift

http://merowing.info/2017/04/using-protocol-compositon-for-dependency-injection/

编辑：一种解决方案可能为整个网络层和服务类编写初始化类，然后摆脱静态函数？但我不确定这是否是一个好方法。

编辑 2：简化代码；

class A{

static func b(completion:...){
    let paramater = ObjectModel(somevariable: SomeClass.Singleton.getVariable()) //Data that I sent on network request
    let router = ServiceRouter(somevariable: SomeClassAgain.Singleton.getsomething()) //Router class which gets parameters, http method etc..

    NetworkClass.performNetworkRequest(sender: object2){ (result) in
        //Result - What I want to test (Write UnitTest about)
    }
}
}

标签： iosswiftunit-testingdependency-injection

解决方案

Use mocking.

class ServiceCallerMock: ServiceCaller {
        override class func performRequest(route: ServiceRouter) -> (Any?) -> Void? {
            //your implementation goes here
        }
    }

You could mock ServiceCaller and override the performRequest method, then change the function to:

static func initAppRequest(_ completion: @escaping (_ appInitRecevingModel: Result<AppInitRecevingModel>) -> Void, serviceCaller: ServiceCaller.Type = ServiceCaller.self) {
    ...
    serviceCaller.performRequest(route: route) { (result) in
    ...
}

Then you could call the initAppRequest function using your mock implementation of ServiceCaller.

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