HTMLProofer
Test your rendered HTML files to make sure they're accurate.
..., we should be able to trace this program's detection of HTML errors back to documented best practices or standards, such as W3 specifications. Third-party modules. We want this product to be useful for continuous integration so we prefer to avoid subjective tests which are prone to false positive results, such as spell checkers, indentation checkers, etc. If you want to work on these items, please see the section on custom tests and consider adding an implementation as a third-party module.