如何使用 Swift 模拟最终类和静态函数以进行单元测试？

Question

我有一个带有static 函数的类。

UserAuthentication.swift

final class UserAuthentication {
    /// Check is logged in
    /// - Returns: boolean true is login, false not login
    @objc public static func isLogin() -> Bool {
        return true
    }
}

我想为checkTermAndCondition 函数编写一个单元测试，在我的HomeInteractor 类中调用它

HomeInteractor.swift

class HomeInteractor: HomeInteractorBusinessLogic {
    var presenter: HomePresenterInterface!
    var worker: HomeWorker = HomeWorker(with: HomeService())
    
    func checkTermAndCondition() {
        if UserAuthentication.isLogin() {
            ///do true case
        } else {
            ///do fasle case
        }
    }
}

有人做过吗？ 感谢您提供的任何帮助。

Answer 1

您不能在 final 类上模拟 static 方法。

您应该将方法更改为class 并使该类成为非最终类或更好，将UserAuthentication 作为协议注入HomeInteractor 并在您的单元测试中注入模拟类型而不是您的实际生产输入。

protocol UserAuthenticator {
    /// Check is logged in
    /// - Returns: boolean true is login, false not login
    static func isLogin() -> Bool
}

final class UserAuthentication: UserAuthenticator {
    @objc public static func isLogin() -> Bool {
        return true
    }
}

final class UserAuthenticationMock: UserAuthenticator {
    static var shouldLogin: Bool = false

    static func isLogin() -> Bool {
        shouldLogin
    }
}


class HomeInteractor: HomeInteractorBusinessLogic {
    var presenter: HomePresenterInterface!
    var worker: HomeWorker = HomeWorker(with: HomeService())
    let userAuthenticator: UserAuthenticator.Type

    init(userAuthenticator: UserAuthenticator.Type) {
        self.userAuthenticator = userAuthenticator
    }

    func checkTermAndCondition() {
        if userAuthenticator.isLogin() {

        } else {

        }
    }
}

为您的产品代码注入UserAuthentication.self，而为测试注入UserAuthenticationMock.self。

let prodHomeInteractor = HomeInteractor(userAuthenticator: UserAuthentication.self)
let testHomeInteractor = HomeInteractor(userAuthenticator: UserAuthenticationMock.self)