There are many online tools available to convert non responsive website into responsive website. Apart from online tools all website designer should know to build Responsive website. For Website Designer or Developer there are many frameworks available in online to help in building responsive websites.
After building Responsive website it is necessary to test that website working properly or not. Anyone can test their website in Responsive website testing tool. http://www.rwdesigntest.com is one of the testing tools to test responsive website. In this tool various screen size available to test website for all screen sizes. There is an option to rotate screen size like we rotate mobile devices. It is free to test all and any type of websites.