The JSR303 draft specification does not discuss or even hint at how the proposed validation rules, expressed as annotations, might be unit tested.

In organizations that routinely use automated unit testing (I work in one), the cost of developing tests for application code often significantly exceeds the cost of writing it.

Therefore, it is insufficient to have a validation mechanism that is itself consise and flexible; one needs to be able to easily write unit tests that verify the applied validations are in fact operating.

In my organization (IBS in Melbourne, Australia) validation business logic is typically a major component of the work we do.

We encountered a similar problem with the JSR181 Web Service metadata annotations. Although its easy to add eg @WebService to a Service-Layer method, its harder to write a unit-integration test that verifies the method is now exposed as a web service endpoint within the web container.

In our case, the main obstacle was that we didn't typically want to test the body of the web service, its business logic, in the same test as verified it was web-exposed. Whether its WS-exposed should be orthogonal to testing what it actually does.

How does this apply to JSR303? Well, for starters, the ability to unit test a particular field validation rule in isolation, without (a) needing eg an app server running, and (b) firing all other validation rules, would be desirable.

The JSR 303 doesn't need to tell you how to write test cases. The purpose of the JSR is to outline the specification so the standard is fully expressed for various vendors to implement. Since most of the classes in the API are interfaces, you're free to create stubs or mock up your own implementations.



I don't mean to start argument here, but you don't understand the purpose of unit testing. Maybe you should grab a book on TDD and do some research on the subject.



You're totally missing the purpose of this JSR. It has *nothing* to do with unit testing. I can't see how its not testable since it doesn't require a container. You're Validators are just Java objects that are passed information that you can mock up.



Try reading the specification. In particular the review of the Validator<T> API.

I'm trying to be helpful, but please read the specification and try to contribute to the growth of the JSR and help flesh out any short comings to the API itself.

Best Regards,
Richard L. Burton III

Here is how I unit test my validations.
If I want to unit test the actual validation implementation, I just instantiate the class and pass various values to it.
If I want to test my domain model validation. I instanciate a validator, I populate one of my domain model class with various wrong values, I check that the validator.validate() return the expect invalid constraints

The JSR runs on plain Java 5. There is no need for an app server.