如何对ActionFilterAttribute进行单元测试

Question

我想测试一个.NET Core 2.0 API项目中的ActionFilterAttribute，想知道最好的方法是什么。请注意，我不是试图通过控制器操作来测试它，只是测试ActionFilterAttribute本身。

我该如何测试呢：

    public class ValidateModelAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext context)
        {
            if (!context.ModelState.IsValid)
            {
                context.Result = new BadRequestObjectResult(context.ModelState);
            }
        }
    }

- ovation22

Answer 1

创建上下文实例并将其传递给过滤器，然后断言期望的行为。

例如。

[TestClass]
public class ValidateModelAttributeTest {
    [TestMethod]
    public void Invalid_ModelState_Should_Return_BadRequestObjectResult() {
        //Arrange
        var modelState = new ModelStateDictionary();
        modelState.AddModelError("", "error");
        var httpContext = new DefaultHttpContext();
        var context = new ActionExecutingContext(
            new ActionContext(
                httpContext: httpContext,
                routeData: new RouteData(),
                actionDescriptor: new ActionDescriptor(),
                modelState: modelState
            ),
            new List<IFilterMetadata>(),
            new Dictionary<string, object>(),
            new Mock<Controller>().Object);

        var sut = new ValidateModelAttribute();

        //Act
        sut.OnActionExecuting(context);

        //Assert
        context.Result.Should().NotBeNull()
            .And.BeOfType<BadRequestObjectResult>();
    }
} 

- Nkosi

---

感谢您的回复。在接受并帮助后，我找到了这个链接：https://dev59.com/A1oV5IYBdhLWcg3wJ8Ab。 - ovation22

@Pure.Krome，您需要向模型状态字典中添加一个模型错误来使其无效。 - Nkosi

我只收到了“null”的返回值，有什么建议吗？ - Frank R. Haugen

@Nkosi 在我看到你的回答评论之前，我添加了这个：问题链接（这样你就知道我的代码了） - Frank R. Haugen

@Nkosi，谢谢，你的帖子总是能够帮助到我。 - johnny 5

Answer 2

这是一个现实生活中的例子，我在操作过滤器属性中也访问了方法信息和参数：

假设我有一个具有ActionAttribute的控制器方法，如下所示：

 public class HomeController : Controller
    {
    ...
    [FeatureFlagActionAtrribute("user", new String[] { "Feature1" })]
    public IActionResult DoSomethingWithFilterAction(String user)
        {...}
    }

http调用将类似于：

/Home/DoSomethingWithFilterAction?user="user1"

现在，我想在这样的上下文中测试ActionAttribute FeatureFlagActionAtrribute功能。

如果您将上述建议应用于此示例，则会像这样（至少对我有效）

 var methodInfoDoSomethingWithFilterAction = typeof(HomeController).GetMethod(nameof(HomeController.DoSomethingWithFilterAction));
    var httpContext = new DefaultHttpContext();
    var routeData = new RouteData();
    FeatureFlagActionAtrribute FeatureFlagActionAtrributeFilter = methodInfoDoSomethingWithFilterAction.GetCustomAttribute<FeatureFlagActionAtrribute>();
    ActionDescriptor actionDescriptor = new ControllerActionDescriptor()
                {
                    ActionName = methodInfoDoSomethingWithFilterAction.Name,
                    ControllerName = typeof(FeatureFlagTest).Name,
                    DisplayName = methodInfoDoSomethingWithFilterAction.Name,
                    MethodInfo = methodInfoDoSomethingWithFilterAction,
                };

    ActionContext actionContext = new ActionContext(httpContext, routeData, actionDescriptor) ;
    var homeController = new HomeController();
    var attribute = new FeatureFlagActionAtrribute("user", new string[] { "feature1" });
    IDictionary<string, object> actionArguments = new Dictionary<string, object>
                {
                    ["user"] = "user1"
                };

    var filterMetadata = new List<IFilterMetadata>() { featureFlagActionAtrributeFilter };

    ActionExecutingContext actionExecutedContext = new 
    ActionExecutingContext(actionContext, filterMetadata, actionArguments, homeController);


    attribute.OnActionExecuting(actionExecutedContext);

然后在ActionFilterAttribute内部：

public override void OnActionExecuting(ActionExecutingContext context)
{
        ControllerActionDescriptor actionDescriptor = (ControllerActionDescriptor)context.ActionDescriptor;
        Debug.Print($"2. @Before Method called {actionDescriptor.ControllerName}Controller.{actionDescriptor.ActionName}");
        var controllerName = actionDescriptor.ControllerName;
        var actionName = actionDescriptor.ActionName;
        IDictionary<object, object> properties = actionDescriptor.Properties;
        ParameterInfo[] paramsOfMethod = actionDescriptor.MethodInfo.GetParameters();
        var fullName = actionDescriptor.DisplayName;

        var paramNameForKeyOfFeature = ParamNameForKeyOfFeature;

        var arguments = context.ActionArguments;

- Roland Roos