I wanted to write some automated tests for CSS changes and bugs, these type of issues are quite prone to regression so re-running the tests has a large benefit.
It is possible to add new assertions to selenium via the user-extensions.js file
The following adds a test for computed style, this only works in firefox as far as I know - but some automation is better than none
//only works in firefox
Selenium.prototype.assertStyle = function(locator, text) {
var params = text.split('=', 2);
var propertyName = params[0];
var expectedValue = params[1];