How to Integrate LinqToSql with Metadata Annotations

Question

I'm just getting started on a new MVC project, and like a good boy I am trying to defer going to the DB for as long as possible. Here's the scoop:

1. I'm planning on using the ComponentModel.DataAnnotations decorations.
2. I'm also planning on using LinqToSql

Is is possible to write a unit test against the DataAnnotations metadata classes? I don't want to put a schema such until as late as possible but I'd still like to write tests to validate the model.

Any ideas on a good approach? Maybe something completely different?

Answer 1

Brad Wilson wrote a great blog post about using DataAnnotations and unit testing them; http://bradwilson.typepad.com/blog/2009/04/index.html

The gist of the testing strategy is this:

1. Write a test to check to make sure you are using the DataAnnotationsModelBinder as the default binder.
2. Use reflection to make sure the DataAnnotation attributes you have decorated the model properties with are what you expect.
3. When testing the Edit or Create controller actions, artificially inject ModelErrors to test that you are handling them as expected.

The rationale is that you treat System.ComponentModel.DataAnnotations like a piece of infrastructure and just test how you have utilized it.