c# - 单元测试依赖于 UserManager 的 Controller 的最佳实践？

Question

我有一个具有以下签名的 Controller :

[Route("api/[controller]")]
[ApiController]
public class UsersController : ControllerBase
{
    private ILogger<UsersController> _logger;

    private readonly UserManager<IdentityUser> _usermanager;

    public UsersController(ILogger<UsersController> logger, UserManager<IdentityUser> usermanager)
    {
        _usermanager = usermanager;
        _logger = logger;
    }

    [HttpGet("{_uniqueid}")]
    public async Task<ObjectResult> GetUser(string _uniqueid)
    {
        //Retrieve the object
        try
        {
            var user = await _usermanager.FindByIdAsync(uniqueid);

            var model = JsonConvert.DeserializeObject<GetUserModel>(user.ToString());

            return new ObjectResult(JsonConvert.SerializeObject(model));
        }

        catch(CustomIdentityNotFoundException e)
        {
            return new BadRequestObjectResult(("User not found: {0}", e.Message));
        }
    }
}

现在我的单元测试是这样的:

public class UsersUnitTests
{
    public UsersController _usersController;

    private UserManager<IdentityUser> _userManager;


    public UsersUnitTests()
    {
        _userManager = new MoqUserManager<IdentityUser>();

        _usersController = new UsersController((new Mock<ILogger<UsersController>>()).Object, _userManager);
    }

    [Fact]
    public async Task GetUser_ReturnsOkObjectResult_WhenModelStateIsValid()
    {
        //Setup

        //Test
        ObjectResult response = await _usersController.GetUser("realuser");

        //Assert
        //Should receive 200 and user data content body
        response.StatusCode.Should().Be((int)System.Net.HttpStatusCode.OK);
        response.Value.Should().NotBeNull();
    }
}

和最小起订量类:

public class MoqUserManager<T> : UserManager<IdentityUser>
{
    public MoqUserManager(IUserStore<IdentityUser> store, IOptions<IdentityOptions> optionsAccessor, 
        IPasswordHasher<IdentityUser> passwordHasher, IEnumerable<IUserValidator<IdentityUser>> userValidators, 
        IEnumerable<IPasswordValidator<IdentityUser>> passwordValidators, ILookupNormalizer keyNormalizer, 
        IdentityErrorDescriber errors, IServiceProvider services, ILogger<UserManager<IdentityUser>> logger) 
        : base(store, optionsAccessor, passwordHasher, userValidators, passwordValidators, keyNormalizer, errors, services, logger)
    {
    }

    public MoqUserManager()
        : base((new MoqUserStore().Store), new Mock<IOptions<IdentityOptions>>().Object, 
            new Mock<IPasswordHasher<IdentityUser>>().Object, new Mock<IEnumerable<IUserValidator<IdentityUser>>>().Object, 
            new Mock<IEnumerable<IPasswordValidator<IdentityUser>>>().Object, new Mock<ILookupNormalizer>().Object, 
            new Mock<IdentityErrorDescriber>().Object, new Mock<IServiceProvider>().Object, new Mock<ILogger<UserManager<IdentityUser>>>().Object)
    {

    }
}

public class MoqUserStore : IdentityUserStore
{
    private Mock<IdentityUserStore> _store;

    public MoqUserStore()
        :base(new Mock<IdentityDbContext>().Object, new Mock<ILogger<IdentityUserStore>>().Object, null)
    {

        _store = new Mock<IdentityUserStore>(new Mock<IdentityDbContext>().Object, new Mock<ILogger<IdentityUserStore>>().Object, null);

        _store.Setup(x => x.FindByIdAsync("realuser", default(CancellationToken))).Returns(Task.Run(() => new IdentityUser("realuser")));
        _store.Setup(x => x.FindByIdAsync("notrealuser", default(CancellationToken))).Throws(new CustomIdentityNotFoundException());
        _store.Setup(x => x.CreateAsync(new IdentityUser("realuser"), default(CancellationToken))).Returns(Task.Run(() => IdentityResult.Success));
    }

    public IdentityUserStore Store { get => _store.Object; }

}

当调用 MoqUserManager 构造函数时，出现 reference not set to an instance of an object 错误。

我的问题是:对于依赖于 UserManager 和/或 SignInManager，什么是模拟 UserStore 依赖项的易于重复的方法？

Answer 1

我考虑了 DI 模型和 Controller 的依赖项。我只需要 UserManager 中的一些方法，所以我从理论上讲从 UsersController 中删除对 UserManager 的依赖，并用一些接口(interface)替换它从 UserManager 实现我需要的相同签名。让我们调用该接口(interface) IMYUserManager:

public interface IMYUserManager
{
    Task<IdentityUser> FindByIdAsync(string uniqueid);
    Task<IdentityResult> CreateAsync(IdentityUser IdentityUser);
    Task<IdentityResult> UpdateAsync(IdentityUser IdentityUser);
    Task<IdentityResult> DeleteAsync(IdentityUser result);
}

接下来，我需要创建一个既派生自 UserManager 又实现 IMYUserManager 的类。这里的想法是，从接口(interface)实现方法将简单地成为派生类的覆盖，这样我就可以绕过 FindByIdAsync (和其余部分)被标记为扩展方法并需要包装在静态类中.这是 MyUserManager:

public class MYUserManager : UserManager<IdentityUser>, IMYUserManager
{
    public MYUserManager(IUserStore<IdentityUser> store, IOptions<IdentityOptions> optionsAccessor, 
        IPasswordHasher<IdentityUser> passwordHasher, IEnumerable<IUserValidator<IdentityUser>> userValidators, 
        IEnumerable<IPasswordValidator<IdentityUser>> passwordValidators, ILookupNormalizer keyNormalizer, 
        IdentityErrorDescriber errors, IServiceProvider services, ILogger<UserManager<IdentityUser>> logger) 
        : base(store, optionsAccessor, passwordHasher, userValidators, passwordValidators, keyNormalizer, errors, services, logger)
    {
    }

    public override Task<IdentityUser> FindByIdAsync(string userId)
    {
        return base.FindByIdAsync(userId);
    }
    //Removed other overridden methods for brevity; They also call the base class method
}

快到家了。接下来，我很自然地更新了 UsersController 以使用 IMYUserManager 接口(interface):

[Route("api/[controller]")]
[ApiController]
public class UsersController : ControllerBase
{
    private ILogger<UsersController> _logger;

    private readonly IMYUserManager _usermanager;

    public UsersController(ILogger<UsersController> logger, IMYUserManager 
        usermanager)
    {
        _usermanager = usermanager;
        _logger = logger;
    }
}

然后，自然而然地，我必须让服务容器可以使用这种依赖关系，以供所有想要享受美食的人使用:

public void ConfigureServices(IServiceCollection services)
{

    services.AddScoped<IMYUserManager, MYUserManager>();


    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}

最后，在验证确实构建之后，我更新了测试类:

public class UsersControllerTests
{
    public UsersController _usersController;

    private Mock<IMYUserManager> _userManager;


    public UsersControllerTests()
    {
        _userManager = new Mock<IMYUserManager>();

        _usersController = new UsersController((new Mock<ILogger<UsersController>> 
            ()).Object, _userManager.Object);
    }

    [Fact]
    public async Task GetUser_ReturnsOkObjectResult_WhenModelStateIsValid()
    {
        //Setup
        _userManager.Setup(x => x.FindByIdAsync("realuser"))
           .Returns(Task.Run(() => new IdentityUser("realuser","realuser1")));

        _usersController.ModelState.Clear();

        //Test
        ObjectResult response = await _usersController.GetUser("realuser");

        //Assert
        //Should receive 200 and user data content body
        response.StatusCode.Should().Be((int)System.Net.HttpStatusCode.OK);
        response.Value.Should().NotBeNull();
    }
}

为什么这是一个好的解决方案？

几件事:

从 UsersController 中删除对 UserManager 的依赖与 DI 模型内联。抽象出依赖项(因此抽象出扩展方法等实现细节)并使它们不仅可用于模拟，而且可用于整个 IServiceCollection 意味着我只有 3 个非常简单的步骤，当我需要为用户管理器实现另一种方法:

1. 将方法签名添加到IMYUserManager
2. 重写方法，调用MYUserManager中的基类实现
3. 在单元测试中模拟新的依赖

我可能会重新审视服务的范围，我选择 AddScoped() 只是为了证明这个概念，但性能和业务需求将选择是否保持不变。