unit-testing - 如何对 ActionFilterAttribute 进行单元测试

Question

我希望在 .NET Core 2.0 API 项目中测试 ActionFilterAttribute，并想知道实现它的最佳方法。请注意，我不是试图通过 Controller 操作来测试它，只是测试 ActionFilterAttribute 本身。

我该如何去测试这个:

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

Answer 1

创建上下文的实例将其传递给过滤器并断言预期的行为

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>();
    }
}