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Answer 1

+4 A:

The same you would normally check for an attribute on a class.

Here's some sample code.

typeof(ScheduleController)
.IsDefined(SubControllerActionToViewDataAttribute, false);

I think in many cases testing for the existence of an attribute in a unit test is wrong. As I've not used MVC contrib's sub controller functionality I can't comment whether it is appropriate in this case though.

RichardOD 2009-08-04 07:47:23

Answer 2

+9 A:

check that

Attribute.GetCustomAttribute(typeof(ScheduleController),
    typeof(SubControllerActionToViewDataAttribute))

isn't null (Assert.IsNotNull or similar)

(the reason I use this rather than IsDefined is that most times I want to validate some properties of the attribute too....)

Marc Gravell 2009-08-04 07:47:54

damn you :)

annakata 2009-08-04 07:49:50

to only check if the attribute is present, which is usually all that is needed for parameterless/propertyless attributes, it's cheaper to use .IsDefined, as it will query the metadata, and not deserialize and instantiate the attribute object.

Lasse V. Karlsen 2009-08-04 07:52:15

Valid point Marc :)

Lasse V. Karlsen 2009-08-04 07:53:27

As is the point about IsDefined being cheaper... but in most cases (and in particular unit tests) you are unlikely to notice the difference. Maybe if it was a tight loop in production code...

Marc Gravell 2009-08-04 07:58:01

@Marc- I agree about that the difference in performance would probably not be noticeable in a unit test. I'd get the attribute if I needed to use it, which as you say is the scenario in most cases. I recently used IsDefined in a framework I was writing to exclude a column in a dropdown of sortable fields- this worked well as I didn't need to use to the attribute itself.

RichardOD 2009-08-04 08:01:50

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Test if a class has an attribute?

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