unit-testing - 对自定义验证过滤器进行单元测试

Question

我有以下属性:

public class ValidateModelAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            if (actionContext.ModelState.IsValid == false)
            {
                actionContext.Response = actionContext.Request.CreateErrorResponse(
                    HttpStatusCode.BadRequest, actionContext.ModelState);
            }
        }
    }  

我有这个通用扩展方法来确定属性是否应用于方法

public static bool ActionHasFilter(this ApiController controller, string action, Type filter)
    {
        var controllerType = controller.GetType();
        var method = controllerType.GetMethod(action);

        object[] filters = method.GetCustomAttributes(filter, true);

        return filters.Any(x=>x.GetType() == filter);

    }

我的问题是如何在不测试 Controller 操作的情况下测试属性是否真正起作用？

假设我有以下实体

public class UserViewModel
{
     [Required]
     public string Name {get; set;}
     [Required]
     [EmailAddress]
     public string Email {get;set;
}

我将如何模拟上下文并检查模型是否有效？

我正在使用 Nunit 和 Moq。

Answer 1

Spock's solution是在正确的轨道上，但对代码有点过于侵入，因为它使 ValidateModelAttribute依赖于 TestableHttpActionContext 的类.我的实现使用了一个公共(public)属性，该属性将用于“注入(inject)”Request单元测试的对象，而作为属性的实现继续使用 Request来自 ActionContext 的对象:

public class ValidateModelAttribute : ActionFilterAttribute
{
    public HttpRequestMessage TestRequestMessage { get; set; }

    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        PerformValidation(actionContext, TestRequestMessage ?? actionContext.Request);
    }

    private void PerformValidation(HttpActionContext actionContext, HttpRequestMessage request)
    {
        if (actionContext.ModelState.IsValid == false)
        {
            actionContext.Response = request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState);
        }
    }
}

单元测试:

[Test]
public void OnActionExecuting_ValidModel_ResponseIsNotSet()
{
    var actionContext = new HttpActionContext();

    actionContext.ModelState.Clear();

    var attribute = new ValidateModelAttribute { TestRequestMessage = new HttpRequestMessage() };

    attribute.OnActionExecuting(actionContext);

    Assert.IsNull(actionContext.Response);
}

[Test]
public void OnActionExecuting_InvalidModel_ResponseIsSetToBadRequest()
{
    var actionContext = new HttpActionContext();

    actionContext.ModelState.AddModelError("key", "error");

    var attribute = new ValidateModelAttribute() { TestRequestMessage = new HttpRequestMessage() };

    attribute.OnActionExecuting(actionContext);

    Assert.AreEqual(HttpStatusCode.BadRequest, actionContext.Response.StatusCode);
}

请注意，我没有使用实际模型来验证 ModelState ，因为这超出了单元测试的范围:我们要测试 ModelState的结果，而不是 ModelState本身。 ;-)