ASP.NET MVC自定义路由约束,依赖注入和单元测试

Question

关于这个主题,我问了另一个问题:

ASP.NET MVC自定义路由约束和依赖注入

这是当前的情况:在我的ASP.NET MVC 3 App上,我有一个如下定义的路由约束:

public class CountryRouteConstraint : IRouteConstraint {

    private readonly ICountryRepository<Country> _countryRepo;

    public CountryRouteConstraint(ICountryRepository<Country> countryRepo) {
        _countryRepo = countryRepo;
    }

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) {

        //do the database look-up here

        //return the result according the value you got from DB
        return true;
    }
}

我正在使用如下:

routes.MapRoute(
    "Countries",
    "countries/{country}",
    new { 
        controller = "Countries", 
        action = "Index" 
    },
    new { 
        country = new CountryRouteConstraint(
            DependencyResolver.Current.GetService<ICountryRepository<Country>>()
        ) 
    }
);

在单元测试部分,我使用了以下代码:

[Fact]
public void country_route_should_pass() {

    var mockContext = new Mock<HttpContextBase>();
    mockContext.Setup(c => c.Request.AppRelativeCurrentExecutionFilePath).Returns("~/countries/italy");

    var routes = new RouteCollection();
    TugberkUgurlu.ReservationHub.Web.Routes.RegisterRoutes(routes);

    RouteData routeData = routes.GetRouteData(mockContext.Object);

    Assert.NotNull(routeData);
    Assert.Equal("Countries", routeData.Values["controller"]);
    Assert.Equal("Index", routeData.Values["action"]);
    Assert.Equal("italy", routeData.Values["country"]);
}

在这里,我无法弄清楚如何传递依赖.任何的想法？

Answer 1

我个人尝试避免在路线约束中执行此类验证,因为用这种方式表达您的意图要困难得多.相反,我使用约束来确保参数的格式/类型正确,并将这些逻辑放在我的控制器中.

在你的例子中,我假设如果国家无效,那么你将回到不同的路线(比如说"未找到国家"页面).依赖于您的路由配置比接受所有国家/地区参数并在您的控制器中检查它们更不可靠(并且更可能被破坏):

    public ActionResult Country(string country)
    {
        if (country == "france") // lookup to db here
        {
            // valid
            return View();
        }

        // invalid 
        return RedirectToAction("NotFound");
    }

除此之外,你在这里想要实现的(正如已经提到的)实际上是一个集成测试.当您发现框架的某些部分妨碍了测试时,那么它可能是重构的时候了.在你的例子中,我想测试

1. 国家得到了正确的验证
2. 我的路由配置.

我们可以做的第一件事就是将Country验证移到一个单独的类中:

public interface ICountryValidator
{
    bool IsValid(string country);
}

public class CountryValidator : ICountryValidator
{
    public bool IsValid(string country)
    {
        // you'll probably want to access your db here
        return true;
    }
}

然后我们可以测试这个单元:

    [Test]
    public void Country_validator_test()
    {
        var validator = new CountryValidator();

        // Valid Country
        Assert.IsTrue(validator.IsValid("france"));

        // Invalid Country
        Assert.IsFalse(validator.IsValid("england"));
    }

CountryRouteConstraint然后我们改为:

public class CountryRouteConstraint : IRouteConstraint
{
    private readonly ICountryValidator countryValidator;

    public CountryRouteConstraint(ICountryValidator countryValidator)
    {
        this.countryValidator = countryValidator;
    }

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
    {
        object country = null;

        values.TryGetValue("country", out country);

        return countryValidator.IsValid(country as string);
    }
}

我们像这样映射我们的路线:

routes.MapRoute(
    "Valid Country Route", 
    "countries/{country}", 
    new { controller = "Home", action = "Country" },
    new { country = new CountryRouteConstraint(new CountryValidator()) 
});

现在,如果你真的觉得有必要测试RouteConstraint,你可以独立测试它:

    [Test]
    public void RouteContraint_test()
    {
        var constraint = new CountryRouteConstraint(new CountryValidator());

        var testRoute = new Route("countries/{country}",
            new RouteValueDictionary(new { controller = "Home", action = "Country" }),
            new RouteValueDictionary(new { country = constraint }),
            new MvcRouteHandler());

        var match = constraint.Match(GetTestContext(), testRoute, "country", 
            new RouteValueDictionary(new { country = "france" }), RouteDirection.IncomingRequest);

        Assert.IsTrue(match);
    }

我个人不打算执行这个测试,因为我们已经抽象了验证代码,所以这只是测试框架.

为了测试路由映射,我们可以使用MvcContrib的TestHelper.

    [Test]
    public void Valid_country_maps_to_country_route()
    {
        "~/countries/france".ShouldMapTo<HomeController>(x => x.Country("france"));
    }

    [Test]
    public void Invalid_country_falls_back_to_default_route()
    {
        "~/countries/england".ShouldMapTo<HomeController>(x => x.Index());
    }

根据我们的路由配置,我们可以验证有效国家/地区是否映射到国家/地区路由,无效国家/地区是否映射到后备路由.

但是,问题的主要内容是如何处理路径约束的依赖关系.上面的测试实际上测试了很多东西 - 我们的路由配置,路由约束,验证器以及可能访问存储库/数据库.

如果您依靠IoC工具为您注入这些工具,那么您将需要模拟验证器和存储库/数据库,并在设置测试时使用IoC工具注册​​这些工具.

如果我们可以控制如何创建约束会更好:

public interface IRouteConstraintFactory
{
    IRouteConstraint Create<TRouteConstraint>() 
        where TRouteConstraint : IRouteConstraint;
}

您的"真实"实现可以使用您的IoC工具来创建IRouteConstraint实例.

我喜欢将我的路由配置放在一个单独的类中,如下所示:

public interface IRouteRegistry
{
    void RegisterRoutes(RouteCollection routes);
}

public class MyRouteRegistry : IRouteRegistry
{
    private readonly IRouteConstraintFactory routeConstraintFactory;

    public MyRouteRegistry(IRouteConstraintFactory routeConstraintFactory)
    {
        this.routeConstraintFactory = routeConstraintFactory;
    }

    public void RegisterRoutes(RouteCollection routes)
    {
        routes.MapRoute(
            "Valid Country", 
            "countries/{country}", 
            new { controller = "Home", action = "Country" },
            new { country = routeConstraintFactory.Create<CountryRouteConstraint>() });

        routes.MapRoute("Invalid Country", 
            "countries/{country}", 
            new { controller = "Home", action = "index" });
    }
}

可以使用工厂创建具有外部依赖性的约束.

这使测试更容易.由于我们只对测试国家路线感兴趣,因此我们可以创建一个仅满足我们需求的测试工厂:

    private class TestRouteConstraintFactory : IRouteConstraintFactory
    {
        public IRouteConstraint Create<TRouteConstraint>() where TRouteConstraint : IRouteConstraint
        {
            return new CountryRouteConstraint(new FakeCountryValidator());
        }
    }

请注意,这次我们使用的FakeCountryValidator包含足够的逻辑来测试我们的路线:

public class FakeCountryValidator : ICountryValidator
{
    public bool IsValid(string country)
    {
        return country.Equals("france", StringComparison.InvariantCultureIgnoreCase);
    }
}

当我们设置测试时,我们将传递TestRouteFactoryConstraint给路由注册表:

    [SetUp]
    public void SetUp()
    {
        new MyRouteRegistry(new TestRouteConstraintFactory()).RegisterRoutes(RouteTable.Routes);
    }

这次我们运行路由测试时,我们没有测试验证逻辑或数据库访问.相反,当提供有效或无效的国家/地区时,我们会对我们的路由配置进行单元测试