如何在AspNet核心集成测试中为Autofac提供模拟接口?

我有一个web api项目,我正在尝试集成测试。控制器是:

[Route("hello")]
public sealed class MyController : Controller
{
   private readonly IFoo _foo;

   public MyController(IFoo foo)
   {
      _foo = foo;
   }

   [HttpGet]
   public IActionResult Hello()
   {
       _foo.MethodToVerify();
       return Ok("Foo");
   }
}

IFoo 在WebApi中使用Autofac注册 ContainerBuilder (建筑商)喜欢

public void Load(ContainerBuilder builder)
{
    builder.RegisterType<FooImplementation>()
           .WithAnotherInterface(builder, "hello")
           .As<IFoo>();
}

在哪里? WithAnotherInterface(string) 扩展方法如下:

public static IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> WithAnotherInterface<TLimit, TReflectionActivatorData, TStyle>(this IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> reg, ContainerBuilder builder, string val)
  : where TReflectionActivatorData : ReflectionActivatorData
{
    builder.RegisterType<AnotherInterfaceImplementation>()
           .Named<IAnotherInterface>("another")
           .WithParameter(ResolvedParameter.ForNamed<IErrorHandler>(val))
           .AutoActivate()
           .SingleInstance();

    return registration;
}

现在在我的测试中,我正在做:

public class MyTest : IClassFixture<WebApplicationFactory<Startup>>
{
    private readonly IFoo _foo;
    private readonly HttpClient _client;
    private readonly WebApplicationFactory<Startup> _factory;

    MyTest(WebApplicationFactory<Startup> factory)
    {
        _foo = Mock.Of<IFoo>();
        _factory = factory;

        _client = _factory.WithWebHostBuilder(builder =>
                  {
                       builder.ConfigureTestContainer<ContainerBuilder>(b =>
                       {
                           b.Register(ctx => _foo).SingleInstance().As<IFoo>();
                       });
                  })
                  .CreateClient();
    }

    [Fact]
    public async Task Test()
    {
       var res = await _client.GetAsync("hello");

       var mock = Mock.Get(_foo);

       mock.Verify(v => v.MethodToVerify(), Times.Once);
    }
}

但是,我的验证失败,记录的已执行调用为零。