webhint : webhint is a linting tool that will help you with your site's accessibility, speed, security and more, by checking your code for best practices and co...
Diagnostic.css : Diagnostic.css is a stylesheet which allows the user to test for common errors in a page's markup.
Also : https://github.com/karlgroves/diagnostic.css
Mink : Mink is an open source acceptance test framework for web applications, written in PHP 5.3.
CodeceptJS : CodeceptJS is a new testing framework for end-to-end testing with WebDriver (or others). It abstracts browser interaction to simple steps that are wri...