Web design comprises many different skills and regulations in the creation and maintenance of websites. Web designers are expected to have a perception of usability and if their role involves creating mark up then they are also expected to be up to date with web accessibility guidelines.
Web designers use a variety of tools which depends on the production process they are involved in. These tools are updated over time by newer standards and software but the principles behind them remain the same and other testing tools for usability and accessibility to ensure their websites meet web accessibility guidelines.