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Accessibility Testing Requirements – Perceivable – Text Alternatives

Posted by Albert Gareev on Sep 24, 2014 | Categories: AccessibilityReviews

In the series of reviews I’m looking at WCAG level A / AA (Web Content Accessibility Guidelines) requirements from testing perspective.

Common Definitions

Human Testing

  • Brief – “You know as you see it” – quick scanning is sufficient to check and make a judgment. This does not include effort of logging defects.
  • Detailed – Either interaction (execution of tests) with the functionality is necessary or detailed review/analysis must be done in order to verify a requirement.

Tool-Assisted Checking

  • Not Available – Tools cannot help in checking for the specified requirement or they help very insignificantly.
  • Partial – Tools provide significant help in checking for the specified requirement, either by saving time in parsing content source or through visualization. Human does the verification and judgment.
  • Full – Tools capable of locating and verifying the specified requirement. Brief review of checking results is sufficient to make a judgment.

Perceivable – Text Alternatives

Tools play major role in parsing content and identifying missing or invalid tags.

Human judgment is required to make sure that alternative text is equivalent and appropriate.

Testers can perform most of testing with input from business SMEs, capable to assess whether textual/audio alternatives convey fully appropriate and adequately detailed information.

Images

All images, form image buttons, and image map hot spots have appropriate, equivalent alternative text.

Human Testing – Detailed

Tool-Assisted Checking – Partial

Tools may check for a presence of some alt text, but unable to judge whether the description is appropriate and sufficient.

Can be covered within GUI Automation.

Non-content images

Images that do not convey content, are decorative, or contain content that is already conveyed in text are given null alt text (alt=””) or implemented as CSS backgrounds.

Human Testing – Brief

Tool-Assisted Checking – Full

Human judgment is required to classify for the tool which images should be excluded as not conveying content.

Can be covered within GUI Automation.

Linked images

All linked images have descriptive alternative text.

Human Testing – Detailed

Tool-Assisted Checking – Partial

Tool may check a presence of some alt text, but unable to judge whether the description is appropriate and sufficient.

Can be covered within GUI Automation.

Complex images

Equivalent alternatives to complex images are provided in context or on a separate (linked and/or referenced via longdesc) page.

Human Testing – Detailed

Tool-Assisted Checking – Partial

Tool may check a presence of some alt text, but unable to judge whether the description is appropriate and sufficient.

Can be covered within GUI Automation.

Form buttons

Form buttons have a descriptive value.

Human Testing – Brief

Tool-Assisted Checking – Partial

Quick review by humans is required. In most cases, it might be covered within functional testing.

Can be covered within GUI Automation.

Form inputs

Form inputs have associated text labels or, if labels cannot be used, a descriptive title attribute.

Human Testing – Brief

Tool-Assisted Checking – Partial

Quick review by humans is required. In most cases, it might be covered within functional testing.

Can be covered within GUI Automation.

Embedded objects

Embedded multimedia is identified via accessible text.

Human Testing – Brief/Detailed

Tool-Assisted Checking – Partial

Quick review by humans is required. However, the embedded content itself is a subject for accessibility testing.


Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported
This work by Albert Gareev is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported.