我是 MVC、单元测试、模拟和 TDD 的新手。我正在尝试尽可能地遵循最佳实践。

我已经为 Controller 编写了单元测试，但我无法测试是否返回了正确的 View 。如果我使用 ViewResult.ViewName，如果我没有在 Controller 中指定 View 名称，测试总是会失败。如果我确实在 Controller 中指定了 ViewName，那么即使 View 不存在，测试也会通过。

我也试过测试 Response.Status 代码，但是它总是返回 200(代码取自 Darin Dimitrov 对 MVC3 unit testing response code 的回答)。我的目标是在创建新 View 时进行经典的红色、绿色重构，并在上线时避免 404 和 System.InvalidOperationException 错误，这可能吗？

下面的代码。

public class BugStatusController : Controller
{
    public ActionResult Index(){
        return View(); // Test always fails as view name isn’t specified even if the correct view is returned.
    }

    public ActionResult Create(){
        return View("Create"); // Test always passes as view name is specified even if the view doesn’t exist.
    }
}

[TestFixture]
public class BugStatusTests
{    
    private ViewResult GetViewResult(Controller controller, string controllerMethodName){
        Type type = controller.GetType();
        ConstructorInfo constructor = type.GetConstructor(Type.EmptyTypes);

        object instance = constructor.Invoke(new object[] {});
        MethodInfo[] methods = type.GetMethods();

        MethodInfo methodInfo = (from method in methods
                                where method.Name == controllerMethodName
                                                    && method.GetParameters().Count() == 0
                                select method).FirstOrDefault();

        Assert.IsNotNull(methodInfo, "The controller {0} has no method called {1}", type.Name, controllerMethodName);

        ViewResult result = methodInfo.Invoke(instance, new object[] {}) as ViewResult;

        Assert.IsNotNull(result, "The ViewResult is null, controller: {0}, view: {1}", type.Name, controllerMethodName);

        return result;
    }

    [Test]
    [TestCase("Index", "Index")]
    [TestCase("Create", "Create")]
    public void TestExpectedViewIsReturned(string expectedViewName, string controllerMethodName){
        ViewResult result = GetViewResult(new BugStatusController(), controllerMethodName);

        Assert.AreEqual(expectedViewName, result.ViewName, "Unexpected view returned, controller: {0}, view: {1}", CONTROLLER_NAME, expectedViewName);
    }

    [Test]
    [TestCase("Index", "Index")]
    [TestCase("Create", "Create")]
    public void TestExpectedStatusCodeIsReturned(string expectedViewName, string controllerMethodName)
    {
        var controller = new BugStatusController();
        var request = new HttpRequest("", "http://localhost:58687/", "");
        var response = new HttpResponse(TextWriter.Null);
        var httpContext = new HttpContextWrapper(new HttpContext(request, response));
        controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), controller);

        ActionResult result = GetViewResult(controller, controllerMethodName);

        Assert.AreEqual(200, response.StatusCode, "Failed to load " + expectedViewName + " Error: "  + response.StatusDescription);
    }
}

最佳答案

I’m new to MVC, Unit Testing, Mocking and TDD. I’m trying to follow best practice as closely as possible.

我很高兴越来越多的开发人员开始为他们的代码编写单元测试，所以恭喜您走上了正确的道路。

if I don’t specify the view name in the controller. If I do specify the ViewName in the controller the test always passes, even if the view doesn’t exist.

当您不在 View 中指定 View 名称时方法指示 MVC 引擎呈现默认 View ，例如

public ActionResult Index() { return View(); }

以上代码将返回一个空的 View 名称，这意味着呈现的 View 将是操作的名称，在本例中它将是Index。

因此，如果您希望测试某个操作是否返回默认 View ，则必须测试返回的 View 名称是否为空

Test always passes as view name is specified even if the view doesn't exist.

为了解释这里发生了什么，我将首先解释操作过滤器的工作原理。

基本上有四种类型的过滤器

• 异常过滤器
• 授权过滤器
• Action 过滤器
• 结果过滤器

我将专注于操作和结果过滤器

操作过滤器是用 IActionFilter 定义的界面

public interface IActionFilter
{
    // Summary:
    //     Called after the action method executes.
    //
    void OnActionExecuted(ActionExecutedContext filterContext);
    //
    // Summary:
    //     Called before an action method executes.
    //
    void OnActionExecuting(ActionExecutingContext filterContext);
}

结果过滤器是用 IResultFilter 定义的界面

public interface IResultFilter
{
    // Summary:
    //     Called after an action result executes.
    //
    void OnResultExecuted(ResultExecutedContext filterContext);
    //
    // Summary:
    //     Called before an action result executes.
    //
    void OnResultExecuting(ResultExecutingContext filterContext);
}

当执行 Controller 的操作时，将按此特定顺序执行以下过滤器:

IActionFilter.OnActionExecuting
IActionFilter.OnActionExecuted
IResultFilter.OnResultExecuting
IResultFilter.OnResultExecuted

当一个 Action 被执行时，另一个组件负责处理你的ActionResult 从您的操作返回并呈现正确的 HTML 以将其发送回客户端，这是处理结果的时间

这种清晰的关注点分离是美妙之处，也是让我们对 Controller 的操作进行单元测试的关键，否则，如果它们耦合在一起，我们将无法单独对操作结果进行单元测试

现在 RazorViewEngine 在执行操作后(处理结果时)尝试查找 View ，这就是为什么即使物理 View 不存在，您的测试也会返回 true。这是预期的行为，请记住您需要单独测试 Controller 的操作。只要您在您的单元测试中声明预期的 View 已呈现，您就完成了单元测试。

var testControllerBuilder = new TestControllerBuilder(); // this is from MVC Contrib
var controller = new MoviesController(
    this.GetMock<IMovieQueryManager>().Object);

testControllerBuilder.InitializeController(controller); // this allows me to use the Session, Request and Response objects as mock objects, again this is provided by the MVC Contrib framework

// I should be able to call something like this but this is not working due to some problems with DLL versions (hell DLL's) between MVC Controb, Moq and MVC itself
// testControllerBuilder.CreateController<MoviesController>();

controller.WithCallTo(x => x.Index(string.Empty)).ShouldRenderDefaultView(); // this is using Fluent MVC Testing

// again instead of the above line I could use the MVC Contrib if it were working....
// var res = sut.Index(string.Empty);
// res.AssertViewRendered().ForView("Index");

关于c# - 如何对 MVC ASP.Net 返回正确的 View 进行单元测试？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13298792/