You can test a URL for mobile friendliness on this google page. (slaw.ca)
Today, the search giant includes mobile friendliness as part of its ranking algorithm, so to give readers what they want, content has to provide a better experience for mobile users. (smallbusinesspr.com)
But this will surely lead to a great decline of quality of search results as the sites which don't have quality content but are mobile friendly will start ranking ahead of those who have genuine quality content but lack mobile friendliness. (dazeinfo.com)