如何使用在方法中具有依赖性的最小起订量对 class 进行单元测试？

Question

我想对验证用户身份的 class AuthClient（使用 Moq）进行单元测试。

问题是我的 AuthenticationService 依赖项没有注入 class。我对如何在不注入依赖项的情况下测试流程感到有点困惑。

[TestClass] 
public class AuthClient 
{
    string Dictionary<string, IList<UserPermissions> _userPermissions;

    User Login(string username, string password)
    {
        IAuthenticationService authenticationService = new AuthenticationService();
        User user = authService.Login(username, password);

        IAuthorizationService authorizationService = new AuthorizationService();
        var permissions = authorizationService.GetPermissions(user);
        _userPermissions.Add(user.Username, permissions);

        return user;
    }
}

我当前的单元测试代码如下所示：

public class UnitTestClass
{
    public string UserName {get;set;}
    public string Password {get;set;}

    [TestInitialize]
    public void Setup() 
    {
        UserName = "test";
        Password = "test123";
    }

    [TestMethod]
    public void When_ValidUserCredentials_Expect_UserIsNotNull()
    {
        var mockAuthenticationService = new Mock<IAuthenticateService>();
        mockAuthenticationService.Setup(m => m.Login(ValidUserName, ValidPassword)).Returns(ValidUserDto);

        var mockAuthorizationService = new Mock<IAuthorizeService>();
        mockAuthorizationService.Setup(m => m.GetAllPermissions(ValidUserId)).Returns(ValidPermissionList);

        var authClient = new Mock<AuthClient>();
        // I want to use mock dependencies here to test flow against mock data
        User user = authClient.Login(UserName, Password); 

        Assert.IsNotNull(user);
    }
}

有什么地方出了问题吗？

Answer 1

Moq 允许您测试 class 依赖于其他 classes/object 的元素（以及许多其他东西）。注意：Moq 不是 IOC 容器。

在您的 AuthClient class 中，您不允许为其提供任何依赖项，而是实例化其自身，例如

IAuthenticationService authenticationService = new AuthenticationService();

相反，您需要在 AuthClient class 上定义一个构造函数，它接受两个对象（它应该依赖于它们），还有其他方法可以 "inject" 依赖关系，但现在我们将使用构造函数注入 (good example)

例如

public class AuthClient 
{
    string Dictionary<string, IList<UserPermissions> _userPermissions;
    private IAuthenticationService _authenticationService;
    private IAuthorizationService _authorizationService;

    public AuthClient(IAuthenticationService authenticationService, IAuthorizationService authorizationService)
    {
        _authenticationService = authenticationService;
        _authorizationService = authorizationService;
    }

    User Login(string username, string password)
    {
        User user = _authenticationService.Login(username, password);

        var permissions = _authorizationService.GetPermissions(user);
        _userPermissions.Add(user.Username, permissions);

        return user;
    }
}

现在，每次您想使用这个 class 时，您都必须告诉它应该使用哪个授权服务和身份验证服务。您已经将 AuthClient 与特定实现分离 - 现在它非常可测试和可重用（如果您想创建一个新的 AuthenticationService 来做一些与旧的完全不同的事情，您只需要编写一个 class实施 IAuthenticationService！）

您现在必须在每次要使用它时包含 AuthClient 的依赖项（将其提供给它的构造函数）。你应该阅读更多关于依赖注入和 IOC（控制反转）的内容（这是一个非常大的话题，有很多不同的方法来做同样的事情），google 是你的朋友。

测试 class 现在应该如下所示：

public class UnitTestClass
{
    public string UserName {get;set;}
    public string Password {get;set;}

    [TestInitialize]
    public void Setup() 
    {
        UserName = "test";
        Password = "test123";
    }

    [TestMethod]
    public void When_ValidUserCredentials_Expect_UserIsNotNull()
    {
        var mockAuthenticationService = new Mock<IAuthenticateService>();
        mockAuthenticationService.Setup(m => m.Login(ValidUserName, ValidPassword)).Returns(ValidUserDto);

        var mockAuthorizationService = new Mock<IAuthorizeService>();
        mockAuthorizationService.Setup(m => m.GetAllPermissions(ValidUserId)).Returns(ValidPermissionList);

        // Here we are "injecting" the dependencies into the AuthClient
        var authClient = new AuthClient(mockAuthenticationService.Object, mockAuthorizationService.Object);
        // This service call will now use the supplied (mocked) services above
        User user = authClient.Login(UserName, Password); 

        Assert.IsNotNull(user);
    }
}

如何使用在方法中具有依赖性的最小起订量对 class 进行单元测试？

How to unit test a class using moq that has dependencies within a method?

c#

unit-testing

moq