How to test custom action filter in ASP.NET Core?

Question

I have created a simple action filter in my ASP.NET Core application, this action filter is suppose to log user's activity:

public class AuditAttribute : IResultFilter
{
    private readonly IAuditService _audit;
    private readonly IUnitOfWork _uow;
    public AuditAttribute(IAuditService audit, IUnitOfWork uow)
    {
        _audit = audit;
        _uow = uow;
    }
    public void OnResultExecuting(ResultExecutingContext context)
    {
        ar model = new Audit
        {
            UserName = context.HttpContext.User,
            //...
        };
        _audit.Add(model);
        _uow.SaveChanges();
    }
    public void OnResultExecuted(ResultExecutedContext context)
    {
    }
}

Now I just wanted to know how can I write unit tests for it. I'm using xUnit and Mock

Mock all the necessary dependencies, exercise the method under test and then verify expected behavior against actual behavior — Nkosi
– Nkosi, Commented Dec 3, 2016 at 18:02
In the same direction that Nkosi said, I would follow the AAA pattern. Arrange Act Assert Take a look here on how to test your controllers learn.microsoft.com/en-us/aspnet/core/mvc/controllers/testing — DOMZE
– DOMZE, Commented Dec 3, 2016 at 20:19

CatNip44 · Accepted Answer · 2019-04-09 10:24:24Z

5

The only way I was able to do this was by creating bare-boned concrete classes and testing the HTTPContext result for what I wanted to achieve. Since I was using concrete classes there was no need for Mock

The setup:

[SetUp]
public void SetUp()
{
   _actionContext = new ActionContext()
   {
      HttpContext = new DefaultHttpContext(),
      RouteData = new RouteData(),
      ActionDescriptor = new ActionDescriptor()
   };
}

The test:

[Test]
public void Should_deny_request()
{
    // Given
    var resourceExecutingContext = new ResourceExecutingContext(_actionContext, new List<IFilterMetadata>(), new List<IValueProviderFactory>());
    var attribute = new YourAttribute();

    // When
    attribute.OnResourceExecuting(resourceExecutingContext);
    var result = (ContentResult) resourceExecutingContext.Result;

    // Then
    Assert.IsTrue(Equals("403", result.StatusCode.ToString()));
}

And this worked for me.

answered Apr 9, 2019 at 10:24

CatNip44

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2 Comments

Patrick Szalapski Over a year ago

new ActionDescriptor() seems to require parameters, and I can't figure them out no matter what I do.

Vinod Over a year ago

Thanks, this was helpful for me to test my exception attribute in asp net code!

akardon · Accepted Answer · 2016-12-28 03:31:08Z

0

According to your code, to do unit test, you need to mock the HttpContext as well. BTW this bit doesn't seem right: UserName = context.HttpContext.User I suppose you meant UserName = context.HttpContext.User.Identity.Name. Anyway this is how you test method should look like:

 public void OnResultExecuting_Test()
 {
     // Arrange sesction :
     var httpContextWrapper = new Moq<HttpContextBase>();
     var genericIdentity = new GenericIdentity("FakeUser","AuthType");
     var genericPrincipal = new GenericPrincipal(genericIdentity , new string[]{"FakeRole"});
     httpContextWrapper.Setup(o=> o.User).Return(genericPrincipal);
     var controller = new FakeController(); // you can define a fake controller class in your test class (should inherit from MVC Controller class)
     controller.controllerContext = new ControllerContext( httpContextWrapper.Object, new RouteData(), controller );
     var audit = new Moq<IUnitOfWork>();
     var uow = new Moq<IAuditService>();
     // more code here to do assertion on audit
     uow.Setup(o=>o.SaveChanges()).Verifiable();
     var attribute= new AuditAttribute(audit.Object,uow.Object);

     // Act Section:
     attribute.OnActionExecuting( filterContext );

     // Assert Section:
     ... // some assertions
     uow.Verify();

 }

answered Dec 28, 2016 at 3:31

akardon

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1 Comment

lbrahim Over a year ago

Where did the filterContext come from?

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