Accessibility testing is a subset of usability testing where in the users under consideration are people with all abilities and disabilities. The significance of this testing is to verify both usability and accessibility.
Accessibility aims to cater people of different abilities such as:
A good web application should cater to all sets of people and NOT just limited to disabled people. These include:
Users with poor communications infrastructure
Older people and new users, who are often computer illiterate
Users using old system (NOT capable of running the latest software)
Users, who are using NON-Standard Equipment
Users, who are having restricted access
The Web Accessibility Initiative (WAI) describes the strategy for preliminary and conformance reviews of web sites. The Web Accessibility Initiative (WAI) includes a list of software tools to assist with conformance evaluations. These tools range from specific issues such as colour blindness to tools that will perform automated spidering tools.
The above said automated accessibility testing tools are very good at identifying pages and lines of code that need to be manually checked for accessibility.
check the syntax of the site's code
Search for known patterns that humans have listed
identify pages containing elements that may cause problems
identify some actual accessibility problems
identify some potential problems
The interpretation of the results from the automated accessibility testing tools requires experience in accessibility techniques with an understanding of technical and usability issues.