Accessibility tests apply verification processes and techniques to a software product to validate whether it meets the expected accessibility requirements and standards. A software is considered fully accessible when it is designed with the purpose that all people, regardless of their unique situations, can perceive, understand, navigate and interact with it.

This type of tests has become very relevant in recent times, given that more and more systems are used, both in workplaces and in daily tasks.

According to the World Health Organization, approximately 15% of the total world´s population experience some kind of disability. This means that 1,000,000,000 people all over the world have some type of disability. As can be seen, this issue impacts a lot of people, who may not be able to access or properly use a system in case it is not designed considering an accessibility perspective.

Accessibility is an attribute that should not be neglected in software products, since it can impact a large number of users. Depending on the specific disability situation, it will be more or less easy for a person to operate a software, according to the degree of adoption of the guidelines established by international standards and good practices.

As a competitive advantage, it is important to think about software accessibility, since it not only increases user participation, but also improves maintenance capacity and efficiency, satisfies the existing and future legal requirements of different countries, which is helpful for internationalization.

Accessibility standards such as the WCAG provide an excellent framework and best practices for making software accessible, and provide excellent guides for accessibility testing. In turn, thanks to the standard´s three conformity levels, it is possible to measure the system´s current state and plan actions to incrementally reach new levels with a future view.

To better understand the WCAG scope, these guidelines range from very technical and very low-level situations, such as that all the web images (Tags in the HTML code) have the alternative attribute (alt) to describe the image, to higher level guidelines such as, for example, that all multimedia content contain subtitles, and all audio contain translation.

There are different support tools for executing accessibility tests, such as Axe and CCA, among others. They provide very good analysis capabilities that allow you to quickly determine the system´s general status in terms of accessibility and provide recommendations for correcting detected errors.

In the event that people with physical disabilities cannot directly use a device, be it a computer or a mobile device, they will need to use assistive tools that help them interact with the systems.

Some of the support tools are:

- Special keyboard: specially designed for users with motor disabilities.
- Screen zoom software: developed to help people with low vision, enlarging the screen and making it easier to read.

- Screen reader: This type of tool is used to read the screen displayed text.

- Voice Recognition Software: By recognizing voice, it changes the spoken word to text and works as system input.

Complementing these tools, it is important to consider manual verification and validation activities, which allow understanding other aspects of accessibility that cannot be obtained through the tool´s results.

To complement verification tools, user or manual tests are also carried out, which allow focusing on the content and not so much on the web structure. For example, verification tools ensure that all images have the alternative attribute (alt), but this type of test verifies that the alternative text is consistent with the image displayed. These tests are performed according to the disability situation. There are 5 categories: Color usage tests, Field focus test, Navigation tests, Zoom tests and Screen reader testing.

For example, Color usage tests aim to verify that a system does not depend on color content to understand its content and how to use it. Regarding Field focus tests, they aim to verify that people with motor disabilities can also use a certain system. These tests seek to verify that a system has the browsers focus indicator enabled and that it is contained in all elements of the web.

By applying a testing strategy that combines tools and manual tests, it is possible to know the level of accessibility offered by the system and detect improvement points to reach greater maturity.