If you utilize structured data markup on your websites, you'll be happy to know that Google has added debugging support in the Webmaster Tools console.
When people begin working with structured data for implementation on their websites, mistakes happen. It's easy to implement partially without realizing it, or simply mark it up incorrectly on the page. But other than copying from guides, there are no easy tools for effectively implementing structured data.
Google added a structured data dashboard to Webmaster Tools last year, and now will show you any errors or problems with your structured data that Google encounters while crawling the website.
This feature has been beta tested with select webmasters since June, and has been enhanced by their suggestions for improved functionality to make it into the newly launched debugging tool.
Google supports rich snippet markups for:
Users can click on each content type to see any relevant errors they may have made in their implementation. They can go and test those snippets with the Structured Data Testing Tool in order to test for errors and correct them, according to what Google discovers. Once you've used the testing tool to recheck any pages with errors, it will be updated automatically in Webmaster Tools to reflect the corrections or the problems the pages may be having.
Because structured data is becoming so much more important for webmasters to implement when it comes to Google search results, having this testing tool will make it much easier for webmasters to ensure everything works correctly and you won't have to wait to do searches on the live search results before determining if there actually is a problem.