A few quick searches discovered that I'm obviously not the first person to have the thought "Can I unit test my CSS?".
I'm wondering if anyone here has taken on CSS Unit Testing successfully? If you've tried and failed, or just have your own theories, please tell me why it (apparently) hasn't been done yet?
You could use Selenium, which is a web testing framework. This way you could assert what styles are to be applied to elements in the DOM etc.
Otherwise, not sure what your aim is. Unit testing is, as the name suggests, testing 'Units', and to me, this only makes sense with code, not css.
You can use PhantomCSS for automatic visual comparison. And then you can create CSS module unit test page that only loads the base CSS styles and displays the component in all it's states, but does not load CSS from other components. And then you can compare it to full CSS file with all modules loaded.
Currently, understanding whether CSS is working properly or not is visually determined. So far, the best way to test it is through installing multiple browsers on your dev machine. Start using tools like Firebug and Web Developer on Firefox, and forget about Unit testing CSS until it becomes Turing complete. :-)
