当被测系统使用外部静态依赖时，如何编写单元测试？答案

【问题标题】：How do I write a unit test when the system under test utilizes external static dependencies?当被测系统使用外部静态依赖时，如何编写单元测试？
【发布时间】：2017-01-26 15:59:40
【问题描述】：

我正在为我的方法创建单元测试

[Authorize]
[HttpPost]
public async Task<JsonResult> UpdateDisplayName(string displayname)
{
    bool status = _myProfileService.UpdateDisplayName(displayname, SessionAdapter.Instance._userDetailsViewModel.id);

    if (status)
        SessionAdapter.Instance._userDetailsViewModel.display_name = displayname;

    return Json(new { status = status, displayname = displayname }, JsonRequestBehavior.AllowGet);
}

我的测试方法是

[TestMethod]
public async Task UpdateDisplayName_Test()
{
    //Arrange
    var controller = new HomeController(userServiceMock.Object, myProfileServiceMock.Object);

    string displayName = "display";
    const string expected = "{ status = False, displayname = display }";
    myProfileServiceMock.Setup(m => m.UpdateDisplayName(It.IsAny<string>(), 1)).Returns(false);

    //var controllerContextMock = new Mock<ControllerContext>();

    //Act
    var result = await controller.UpdateDisplayName(displayName) as JsonResult;

    //Assert
    Assert.AreEqual(expected, result.Data.ToString());
}

我的会话信息类在下面，这个类我在会话适配器中使用

  public  class SessionInfo
    {
        public string Id { set; get; }
        public string Email { set; get; }
        public string UserName { set; get; }
        public UserDetailsViewModel _userDetailsViewModel { set; get; }
        public string permission { set; get; }

        //public string organization { set; get; }
        public OrganizationViewModels Organization { set; get; }
        public List<UserTeamModels> teams { set; get; }
        public string status { set; get; }
        public string role { set; get; }
        public List<string> roles { set; get; }
    }

我无法实例化SessionAdapter。如何对此进行单元测试？

我的 Interface 和 sessionadapter 类如下所示

public interface ISessionAdapterService
    {
        void Clear();
        void Abandon();
        bool DoesSessionExists { get; }
        SessionInfo Instance { get; set; } 
    }


    public class SessionAdapterService : ISessionAdapterService
    {
        private string sessionKey = "sessionInfoKey";

        public bool DoesSessionExists
        {
            get
            {
                return HttpContext.Current.Session[sessionKey] == null ? false : true;
            }

        }

        public SessionInfo Instance
        {
            get
            {
                return HttpContext.Current.Session[sessionKey] == null ? null : (SessionInfo)HttpContext.Current.Session[sessionKey];
            }
            set
            {
                HttpContext.Current.Session[sessionKey] = value;
            }
        }



        public void Abandon()
        {

            HttpContext.Current.Session.Abandon();
            HttpContext.Current.Session[sessionKey] = null;
        }

        public void Clear()
        {
            HttpContext.Current.Session.Clear();

        }
    }

我的测试用例和下面的答案一样

[TestMethod]
public async Task UpdateDisplayName_Test() {
    //Arrange
    var mySessionAdaptorService = new Mock<ISessionAdaptorService>();

    var controller = new HomeController(userServiceMock.Object, myProfileServiceMock.Object, mySessionAdaptorService.Object);

    var displayName = "display";
    var status = false;
    var id = 1;
    myProfileServiceMock.Setup(m => m.UpdateDisplayName(It.IsAny<string>(), id)).Returns(status);
    mySessionAdaptorService.Setup(m => m.Instance.Id).Returns(id);

    //Act
    var result = await controller.UpdateDisplayName(displayName) as JsonResult;

    //Assert
    Assert.IsNotNull(result); 
}

代码更新。请找到我用于 SessionAdapter 类和 ISessionAdapter 接口以及实现的以下代码。请给出您的建议是正确的方法。

     public interface ISessionInfo
        {
            string Id { set; get; }
            string Email { set; get; }
            string UserName { set; get; }
            UserDetailsViewModel _userDetailsViewModel { set; get; }
            string permission { set; get; }

            OrganizationViewModels Organization { set; get; }
            List<UserTeamModels> teams { set; get; }
            string status { set; get; }
            string role { set; get; }
            List<string> roles { set; get; }
        }

        public  class SessionInfo : ISessionInfo
        {
            public string Id { set; get; }
            public string Email { set; get; }
            public string UserName { set; get; }
            public UserDetailsViewModel _userDetailsViewModel { set; get; }
            public string permission { set; get; }

            //public string organization { set; get; }
            public OrganizationViewModels Organization { set; get; }
            public List<UserTeamModels> teams { set; get; }
            public string status { set; get; }
            public string role { set; get; }
            public List<string> roles { set; get; }
        }

 public interface ISessionAdapter
    {
        void Clear();
        void Abandon();
        bool DoesSessionExists { get; }
        ISessionInfo Instance { get; set; }

    }


    public class SessionAdapter : ISessionAdapter
    {
        private string sessionKey = "sessionInfoKey";

        public bool DoesSessionExists
        {
            get
            {
                return HttpContext.Current.Session[sessionKey] == null ? false : true;
            }
        }

        public ISessionInfo Instance
        {
            get
            {
                return HttpContext.Current.Session[sessionKey] == null ? null : (SessionInfo)HttpContext.Current.Session[sessionKey];
            }
            set
            {
                HttpContext.Current.Session[sessionKey] = value;
            }
        }

        public void Abandon()
        {

            HttpContext.Current.Session.Abandon();
            HttpContext.Current.Session[sessionKey] = null;
        }

        public void Clear()
        {
            HttpContext.Current.Session.Clear();

        }

【问题讨论】：

什么是 SessionAdapter？
会话适配器是我的静态类，具有一些属性，我在登录时设置这些详细信息
你不能实例化一个静态类。这就是静态的含义。
您遇到错误了吗？如果是这样，您应该将其包含在您的问题中。作为单元测试设置的一部分，您可能能够摆脱初始化 SessionAdapter 静态类的属性。但实际上，这听起来像是一个外部依赖项，不应该是静态的——相反，您应该将其设为非静态类并将其作为依赖项注入，就像您对用户和配置文件服务所做的那样。这将允许您模拟它以进行单元测试。编写可测试的代码很重要，静态类不适合可测试的代码。
顺便说一句，您的expected 字符串不是有效的 JSON，假设它运行完成，您的操作方法几乎肯定会生成有效的 JSON。您需要解决此问题才能使测试成功。

标签： c# .net asp.net-mvc unit-testing moq

【解决方案1】：

抽象外部依赖并将其注入控制器。只要它保持静态，测试方面就没有什么可做的了

抽象可以是这样的

public interface ISessionAdapterService {
    int Id { get; }
    string DisplayName { get; set; }
}

使用以下实现。

public class SessionAdapterService : ISessionAdapterService {
    public string DisplayName { 
        get { return SessionAdapter.Instance._userDetailsViewModel.display_name; } 
        set { SessionAdapter.Instance._userDetailsViewModel.display_name = value; } 
    }

    public int Id {
        get { return SessionAdapter.Instance._userDetailsViewModel.id; }
    }
}

控制器需要使用抽象作为依赖

[Authorize]
[HttpPost]
public async Task<JsonResult> UpdateDisplayName(string displayname) {
    bool status = _myProfileService.UpdateDisplayName(displayname, sessionAdapterService.Id);

    if (status)
        sessionAdapterService.DisplayName = displayname;

    return Json(new { status = status, displayname = displayname }, JsonRequestBehavior.AllowGet);
}

假设sessionAdapterService 是一个注入的ISessionAdapterService

单元测试现在可以模拟外部依赖并将其注入控制器。

[TestMethod]
public async Task UpdateDisplayName_Test() {
    //Arrange
    var mySessionAdaptorService = new Mock<ISessionAdaptorService>();

    var controller = new HomeController(userServiceMock.Object, myProfileServiceMock.Object, mySessionAdaptorService.Object);

    var displayName = "display";
    var status = false;
    var id = 1;
    myProfileServiceMock.Setup(m => m.UpdateDisplayName(It.IsAny<string>(), id)).Returns(status);
    mySessionAdaptorService.Setup(m => m.Id).Returns(id);

    //Act
    var result = await controller.UpdateDisplayName(displayName) as JsonResult;

    //Assert
    Assert.IsNotNull(result);
    dynamic data = result.Data;
    Assert.IsNotNull(data);
    Assert.AreEqual(displayName, (string)data.displayname);
    Assert.AreEqual(status, (bool)data.status);
}

更新。

基于您的 cmets 更新了 SessionInfo 类的抽象

public interface ISessionInfo {
    string Id { set; get; }
    string Email { set; get; }
    string UserName { set; get; }
    UserDetailsViewModel _userDetailsViewModel { set; get; }
    string permission { set; get; }

    OrganizationViewModels Organization { set; get; }
    List<UserTeamModels> teams { set; get; }
    string status { set; get; }
    string role { set; get; }
    List<string> roles { set; get; }
}

public class SessionInfo : ISessionInfo { ... }

public interface ISessionAdapterService {
    void Clear();
    void Abandon();
    bool DoesSessionExists { get; }
    ISessionInfo Instance { get; set; } 
}

我还建议您审查您的模型设计。它非常脆弱，并迫使会话信息类与实现问题紧密耦合。

【讨论】：