带有OWIN TestServer和AutoFac的WebApi2-LifetimeScope已废弃

Question

我在使用Owin.TestServer测试应用程序时遇到麻烦。 我找不到任何有用的方法，希望这是社区可以提供帮助的简便方法：)

最近，我开始为使用OWIN和AutoFac for DI的WebApi应用程序编写集成测试。 我总共有3个集成测试。 当我分别运行每个测试时，它们都通过了。 但是，当我一次运行所有测试时，由于以下AutoFac错误，只有第一个成功，而其他两个则失败：

System.AggregateException: One or more errors occurred. ---> 
System.ObjectDisposedException: Instances cannot be resolved and nested lifetimes cannot be created from this LifetimeScope as it has already been disposed.

Stacktrace指示该错误来自Owin的AutoFac中间件。

我为测试进行了以下设置：

[TestClass]
public class DinnerListControllerTests
{
    private TestServer _server;
    private TransactionScope _transactionScope;

    [TestInitialize]
    public void Init()
    {
        _transactionScope = new TransactionScope(TransactionScopeOption.RequiresNew);
        _server = TestServer.Create<Startup>();
    }

    [TestCleanup]
    public void Dispose()
    {
        _server?.Dispose();
        _transactionScope?.Dispose();
    }

    [TestMethod]
    public void GetAllLists()
    {
        var response = _server.HttpClient.GetAsync("/api/dinnerlists").Result;
        response.IsSuccessStatusCode.Should().BeTrue("there should be no error");
        var result = response.Content.ReadAsAsync<IEnumerable<DinnerListDTO>>().Result;
        result.Should().NotBeNull().And.HaveCount(5);
    }

    [TestMethod]
    public void GetActiveListsReturnsTwoLists()
    {
        var response = _server.HttpClient.GetAsync("/api/dinnerlists/active").Result;
        response.IsSuccessStatusCode.Should().BeTrue();

        var result = response.Content.ReadAsAsync<IEnumerable<DinnerListDTO>>().Result;
        result.Should()
            .NotBeNullOrEmpty()
            .And.HaveCount(2)
            .And.OnlyContain(dto => dto.OpenUntil.CompareTo(DateTime.Now) > 0);
    }
}

GetAllLists测试将正确执行，但是第二个测试将失败，并显示上述消息。

我尝试了不同的依存关系注册范围，但没有帮助。 以下是我的AutoFac配置，启动类和示例AutoFac模块：

AutoFacConfig.cs

public class AutoFacConfig
{
    private static IContainer _container;
    public static IContainer Container => _container ?? (_container = BuildContainer());

    public static void ConfigureAutoFac(HttpConfiguration config)
    {
        if (config == null)
            throw new ArgumentNullException(nameof(config));

        FluentValidationModelValidatorProvider.Configure(config,
            provider => provider.ValidatorFactory = new AutoFacValidatorFactory(Container));

        config.DependencyResolver = new AutofacWebApiDependencyResolver(Container);
    }

    private static IContainer BuildContainer()
    {
        var autoFacBuilder = new ContainerBuilder();
        var assembly = Assembly.GetExecutingAssembly();
        autoFacBuilder.RegisterApiControllers(assembly).InstancePerRequest();

        autoFacBuilder.RegisterType<DinnerDbContext>().InstancePerRequest();
        autoFacBuilder.RegisterModule<RepositoryModule>();
        autoFacBuilder.RegisterModule<ServicesModule>();
        autoFacBuilder.RegisterModule<ValidationModule>();
        autoFacBuilder.RegisterModule<AutoMapperModule>();
        autoFacBuilder.RegisterModule<AutofacWebTypesModule>();

        return autoFacBuilder.Build();
    }
}

Startup.cs：

public class Startup
{
    public void Configuration(IAppBuilder appBuilder)
    {
        var httpConfiguration = new HttpConfiguration();

        WebApiConfig.Register(httpConfiguration);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

        AutoFacConfig.ConfigureAutoFac(httpConfiguration);
        AutoMapperConfig.RegisterMappings();

        appBuilder.UseAutofacMiddleware(AutoFacConfig.Container);
        appBuilder.UseAutofacWebApi(httpConfiguration);
        appBuilder.UseWebApi(httpConfiguration);
    }
}

示例AutoFac模块：

public class RepositoryModule : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        var assembly = System.Reflection.Assembly.GetExecutingAssembly();
        builder.RegisterAssemblyTypes(assembly)
            .Where(type => type.Name.EndsWith("Repository"))
            .AsImplementedInterfaces()
            .InstancePerRequest();
    }
}

---

编辑-解决方案

@Eris的建议很有道理-我的AutoFacConfig类使用的是静态方法和成员，这意味着Container属性在后续测试中存在，并且不再被创建，并且被标记为已处置。

我决定重构代码，以便AutoFacConfig不再使用静态成员，因为我不想在应用程序关闭时处理容器。

AutoFacConfig.cs：

public class AutoFacConfig
{
    private IContainer _container;
    public IContainer Container
    {
        get { return _container ?? (_container = BuildContainer()); }
    }

    public void ConfigureAutoFac(HttpConfiguration config)
    {
        //...
    }

    private IContainer BuildContainer()
    {
        var autoFacBuilder = new ContainerBuilder();
        //...
        return autoFacBuilder.Build();
    }
}

Startup.cs

public class Startup
{
    public void Configuration(IAppBuilder appBuilder)
    {
        var httpConfiguration = new HttpConfiguration();
        var autofacConfig = new AutoFacConfig();  // create instance of AutoFacConfig           
        autofacConfig.ConfigureAutoFac(httpConfiguration); // configure autofac

        appBuilder.UseAutofacMiddleware(autofacConfig.Container);
        appBuilder.UseAutofacWebApi(httpConfiguration);
        appBuilder.UseWebApi(httpConfiguration);
    }
}

Answer 1

我怀疑是AutoFacConfig引起了问题：

    public static IContainer Container => _container ?? (_container = BuildContainer());

在这种情况下， _container不为null，而是处于“ Disposed”状态。 如果您无条件重新创建它，则它应该可以工作。 （我还不熟悉C＃6语法，因此这可能并不完全正确）

    public static IContainer Container => _container = BuildContainer();

替代答案： 在自托管的OWIN Web API中，如何在关闭时运行代码？

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        var context = new OwinContext(app.Properties);
        var token = context.Get<CancellationToken>("host.OnAppDisposing");
        if (token != CancellationToken.None)
        {
            token.Register(() =>
            {
                // code to run 
                // null out disposable resources
            });
        }
    }
}