c# - .net core 3.0，服务未使用 HostBuilder 注册以进行集成测试

Question

存储库可在此处获得:https://github.com/ranouf/TestingWithDotNetCore3_0/tree/WithDatabase

我正在寻找一种方法将我的集成测试从 .Net Core 2.0 升级到 3.0。我真的尽了最大努力来注入(inject)一个该死的服务，正如你所看到的，我尽我所能:

        var hostBuilder = new HostBuilder()
            .UseServiceProviderFactory(new AutofacServiceProviderFactory())
            .ConfigureLogging(logging =>
            {
                logging.ClearProviders();
                logging.AddXunit(Output);
            })
            .ConfigureServices(services =>
            {
                services.AddAutofac();
                services.AddSingleton<IMyService, MyService>(); //Here
            })
            .ConfigureContainer<ContainerBuilder>(builder =>
            {
                builder.RegisterType<MyService>().As<IMyService>().InstancePerLifetimeScope();//Here
            })
            .ConfigureWebHost(webHost =>
            {
                // Add TestServer
                webHost
                    .UseStartup<TestStartup>()
                    .UseTestServer()
                    .ConfigureServices(services =>
                    {
                        services.AddSingleton<IMyService, MyService>();//Here
                        services.AddAutofac();
                        services
                            .AddControllers()
                            .AddApplicationPart(typeof(TestStartup).Assembly);
                    })
                    .ConfigureTestServices(services =>
                    {
                        services.AddSingleton<IMyService, MyService>();//Here
                        services.AddAutofac();
                        services
                            .AddControllers()
                            .AddApplicationPart(typeof(TestStartup).Assembly);
                    })
                    .ConfigureTestContainer<ContainerBuilder>(builder =>
                    {
                        builder.RegisterType<MyService>().As<IMyService>().InstancePerLifetimeScope();//Here
                    });
            });

但是你猜怎么着？它根本不起作用......我真的不知道如何让 HostBuilder 理解......当然，我尝试过只保留一种方式来注入(inject)我的服务

所以当我想获得服务时:

    Host = hostBuilder.Start();
        Server = Host.GetTestServer();
        Client = Host.GetTestClient();

        using (var scope = Host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;
            try
            {
                var myService = services.GetRequiredService<MyService>();
            }
            catch (Exception ex)
            {
                Output.WriteLine("HOST: " + ex.Message);
            }
        }
        using (var scope = Server.Services.CreateScope())
        {
            var services = scope.ServiceProvider;
            try
            {
                var myService = services.GetRequiredService<MyService>();
            }
            catch (Exception ex)
            {
                Output.WriteLine("SERVER: " + ex.Message);
            }
        }

错误信息是:

The requested service 'MyAPI.Services.MyService' has not been registered. To avoid this exception, either register a component to provide the service, check for service registration using IsRegistered(), or use the ResolveOptional() method to resolve an optional dependency.

如何在 HostBuilder 中成功注入(inject)服务？

Answer 1

您已经注册，每当有人请求 IMyService 时，都会给他们一个 MyService 的实例 - 但您直接请求 MyService 而 DI 没有对此一无所知。

您需要将注册更改为:

builder.RegisterType<MyService>().InstancePerLifetimeScope();

或者要求接口(interface)而不是类:

services.GetRequiredService<IMyService>();

另外，你只需要在ConfigureContainer方法中注册即可。