Google in 2016 has made new changes to its Structured Data testing tool because of the new features such as Rich Cards focusing on mobile devices user experience. Google also renamed Rich Snippets to reflect these latest changes, now Snippets are called Rich Results.
Updated Google Structured Data Testing Tool compared to the older version has no difference in terms of its usage to identify any errors or warnings. However, the newly updated testing tool has new features for testing out how Rich Cards will look for mobile devices (see image below)
Updated Video Tutorial Showing How to Use Google Structured Data Testing Tool
Older Version of the Testing Tool
Main reason you would want to use this tool is to test your website markup validation to see if there are any errors, particularly for the new features such as Rich Cards.
About Testing Tool Warnings
When validating your markup, you may get warnings, don’t be alarmed, you can if you choose ignore these warnings altogether because the tool throws warnings for Structured Data that is optional. Meaning, if there are no errors with your markup, then, its valid markup. If there are warnings, then, your markup is still valid but you can further enhance it by making sure that they optional fields are also structured.
When To Use This Tool?
Anytime you change any structured of your site you should double check its validation using this new tool. Also, it doesn’t hurt to conduct quick URL copy and paste anytime you create new content that is structured using microdata or JSON-LD formats on your website.