Accessibility testing is defined as a subcategory of usability testing that is geared toward users of all disabilities and abilities. The aim of this testing is to check not only accessibility but usability too.
The key principle of Web accessibility is designing software and Web sites that are flexible to meet different user preferences, situations and needs. This flexibility also benefits people without disabilities in assured situations such as people with "temporary disabilities" such as a broken arm, people using a slow Internet connection etc.
To read more about the myths associated with it, check Bugraptors blog below: