Software Accessibility Testing is a set of tests which consists of testing how useful is a software product for people with certain disabilities or limitations due to advanced age. These tests also aim to ensure that each component can be easily used by people with their respective limitations.

Accessibility testing is similar to usability testing; however, these tests focus on checking usability and accessibility together. The tester will test the system as individuals with some impairments such as visual impairment, non-functional organs, learning disabilities and hearing impairment.

Since the ideal scenario would be to have testers with these limitations in order to meet the user's expectations, however, we know that it is not possible to have a professional with every limitation for the system, so for this reason we must broadly understand the limitations, in order to meet them.

Web and mobile accessibility bring benefits to the organization, improving the user experience and satisfaction of those individuals who have certain limitations, providing them with more autonomy when using the system, without needing help to perform simple tasks.

Regarding the different types of disabilities or limitations considered in software usability (see here), we can find the following:

- Visual impairment: it includes complete blindness, low vision, light sensitivity and people with color blindness.
- Low vision: Users who have compromised vision and usually use screen magnifiers because they have difficulty with close or far vision.
- Blindness: These are people who can´t see at all and use screen readers to browse websites.
- Color blindness: It is a type of visual impairment that affects 10% of the world's male population.
- Hearing Impairment: it includes hearing difficulties or total hearing impairment.
- Learning Disability: These are problems in which the person finds words too difficult. Therefore, the tester should check if the language is compatible for the user to read and if the used words are easy to understand.
- Physical disability: The test is performed for people with difficulty using the keyboard or mouse, which includes hand movements and muscle slowness.
- Elderly: It is common for the elderly to have impaired vision as a natural aging result. A website where the user can increase the font size would be useful for them.
- Language: Webs and apps should consider other languages, as not all the world´s population understands English.

How is an accessibility test performed? An accessibility test can be performed using the black box testing methodology, which implies, for example, that the tester verifies through extensions available in the software market if a person with color blindness will be able to visualize the interface components in a clear and pleasant way. Also, the tester must verify if a person with myopia will be able to read the instructions and if the information is easy to understand.

Regarding best practices for accessible software, there are some good practices that aim to expand public diversification, in addition to being an excellent opportunity to review all digital communication, promoting an important social role that is digital inclusion. Regarding these practices, these are some useful tips for accessibility testing in any given project:

- Font size should be easy to read
- Avoid using the font in italic style, as this formatting is difficult to read
- Colors must follow rules so that all users can identify the elements
- Every informative element, such as an icon for example, needs a textual element that describes it
- Links must be clearly identified by visual elements
- It is recommended that every site have audio content for its content description.
- All non-text digital content, such as images, must contain a description

It is not possible to guarantee 100% accessibility in a software, but we can think about how to promote a good experience for all users. Not every webpage will go through an accessibility evaluation by experts and a whole group of paid test subjects.

But any web developer can learn the principles of accessibility, try to apply them in his code, and send the results of his work to user mailing lists to discover other problems, thus gaining new knowledge that he can apply in future development.