在ServiceStack OrmLite MVC应用中测试/模拟AuthUserSession的问题

问题背景 #

现有基于ServiceStack OrmLite的MVC应用，添加控制器测试时，其他依赖注入的模拟均正常，但AuthUserSession始终抛出空引用异常。所有控制器都继承自基础控制器_Controller，其中包含：

public MyAuthUserSession AuthUserSession => SessionAs<MyAuthUserSession>();

MyAuthUserSession继承自AuthUserSession，包含自定义权限检查方法，控制器中会通过该属性做权限校验，例如：

model.CanEdit = AuthUserSession.HasEntityPermission(PermissionType.Update, PermissionEntity.MyEntity);

已尝试但无效的方案 #

• 配置测试AppHost：完全照搬生产环境的AuthFeature配置，但会话始终未被填充

  public class TestAppHost : AppHostBase
  {
      public TestAppHost() : base("Test Service", typeof(LocationsService).Assembly) { }
  
      public override void Configure(Container container)
      {
          Plugins.Add(new AuthFeature(() => new MyAuthUserSession(), new IAuthProvider[] { new BasicAuthProvider() })
          {
              IncludeAssignRoleServices = false,
              IncludeAuthMetadataProvider = false,
              IncludeRegistrationService = false,
              GenerateNewSessionCookiesOnAuthentication = false,
              DeleteSessionCookiesOnLogout = true,
              AllowGetAuthenticateRequests = req => true
          });
      }
  }
  

• 手动保存会话：通过AuthenticateService保存测试会话，但与控制器的SessionAs调用不关联

  var authService = appHost.Container.Resolve<AuthenticateService>();
  var session = new MyAuthUserSession();
  authService.SaveSessionAsync(session).Wait();
  

• 直接注册IAuthSession实例：在AppHost中注册会话实例，无任何效果

  TestMode = true;
  container.Register<IAuthSession>(new MyAuthUserSession { UserAuthId = "1" });
  

• 修改ControllerContext.HttpContext：尝试往请求项中添加会话，未成功

关键差异发现 #

API服务中（继承自Service）仅需注册IAuthSession即可正常获取会话，但MVC控制器（继承自ServiceStackController）同样操作无效。简化测试代码后，即使使用空控制器+基础配置的AppHost，调用SessionAs仍抛出空引用：

简化测试代码 #

TestAppHost配置：

public class TestAppHost : BasicAppHost
{
    public TestAppHost() : base(typeof(LocationsService).Assembly) { }

    public override void Configure(Container container)
    {
        container.Adapter = new UnityIocAdapter(Repository.Container.Instance);
        Plugins.Add(new AuthFeature(() => new AuthUserSession(),
    new IAuthProvider[] {
        new BasicAuthProvider(),       // HTTP Basic Auth登录
        new CredentialsAuthProvider(), // 用户名密码表单登录
    }));

        container.Register<ICacheClient>(new MemoryCacheClient());
        var userRepo = new InMemoryAuthRepository();
        container.Register<IAuthRepository>(userRepo);
        container.Register<IAuthSession>(new AuthUserSession());
    }
}

空控制器：

public class EmptyController: ServiceStackController
{
    public EmptyController() {}

    public AuthUserSession AuthUserSession => SessionAs<AuthUserSession>();
}

测试调用代码：

_appHost = new TestAppHost();
_appHost.Init();
var contr = _appHost.Resolve<EmptyController>();
var session = contr.AuthUserSession; // 此处抛出空引用异常

异常堆栈跟踪 #

at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider)
at ServiceStack.Host.NetCore.NetCoreRequest.TryResolve[T]()
at ServiceStack.ServiceStackHost.GetCacheClient(IRequest req)
at ServiceStack.ServiceStackProvider.get_Cache()
at ServiceStack.ServiceStackProvider.SessionAs[TUserSession]()
at ServiceStack.Mvc.ServiceStackController.SessionAs[TUserSession]()
at WebApplication.Controllers._Controller.get_AuthUserSession() in _Controller.cs:line 93
at WebApplication.Controllers.MyController.Common(PageAction action, MyDataModel model) in MyController.cs:line 288
at WebApplication.Controllers.MyController.Show(Int64 id) in MyController.cs:line 157
at WebApplication.UnitTests.Controllers.MyControllerTests.Show_WithReadPrivileges_ReturnsExpectedSettingValue() in MyControllerTests.cs:line 115

核心需求 #

由于是遗留应用，无法修改AuthUserSession属性（全项目约1000处引用，重构成本极高），且该属性为常规属性，无法用NSubstitute模拟返回值。需要找到一种无需大规模重构的方式，让ServiceStackController的SessionAs<MyAuthUserSession>()返回指定的测试会话。

内容的提问来源于stack exchange，提问作者Irish Yobbo