所以你可以通过引入一个抽象级别来削弱耦合：

public interface IMyService
{
    MembershipCreateStatus CreateUser(string username,string password,string email);
}

然后有一些使用当前成员资格提供者的实现：

public class MyService: IMyService
{
    public MembershipCreateStatus CreateUser(string username,string email)
    {
        MembershipCreateStatus status;
            Membership.CreateUser(username,password,email,out status);
        return status;
    }
}

最后是控制器：

public class AccountController : Controller
{
    private readonly IMyService _service;
    public AccountController(IMyService service)
    {
        _service = service;
    }
 
    [HttpPost]
    public ActionResult Register(RegisterModel model)
    {
        if (ModelState.IsValid)
        {
            // Attempt to register the user
            var status = _service.CreateUser(model.UserName,model.Email);
            if (status == MembershipCreateStatus.Success)
            {
                FormsAuthentication.SetAuthCookie(model.UserName,false /* createPersistentCookie */);
                return RedirectToAction("Index","Home");
            }
            else
            {
                ModelState.AddModelError("",ErrorCodeToString(createStatus));
            }
        }
 
        // If we got this far,redisplay form
        return View(model);
    }
}

好了,既然我们已经削弱了耦合,我们可以使用模拟框架来模拟单元测试中的服务并使其变得微不足道.

例如,使用Rhino Mocks,您可以创建以下测试以涵盖2个故障情况：

[TestMethod]
public void Register_Action_Should_Redisplay_View_If_Model_Is_Invalid()    
{
    // arrange
    var sut = new AccountController(null);
    var model = new RegisterModel();
    sut.ModelState.AddModelError("","invalid email");
 
    // act
    var actual = sut.Register(model);
 
    // assert
    Assert.IsInstanceOfType(actual,typeof(ViewResult));
    var viewResult = actual as ViewResult;
    Assert.AreEqual(model,viewResult.Model);
}
 
[TestMethod]
public void Register_Action_Should_Redisplay_View_And_Add_Model_Error_If_Creation_Fails()
{
    // arrange
    var service = MockRepository.GenerateStub<IMyService>();
    service
        .Stub(x => x.CreateUser(null,null))
        .IgnoreArguments()
        .Return(MembershipCreateStatus.InvalidEmail);
    var sut = new AccountController(service);
    var model = new RegisterModel();
 
    // act
    var actual = sut.Register(model);
 
    // assert
    Assert.IsInstanceOfType(actual,viewResult.Model);
    Assert.IsFalse(sut.ModelState.IsValid);
}

最后的测试是成功案例.我们仍然有一个问题.问题是以下行：

FormsAuthentication.SetAuthCookie(model.UserName,false);

这是什么？这是一个静态方法调用.因此,我们采用与成员资格提供程序相同的方式来削弱控制器和表单身份验证系统的耦合.