Difference between revisions of "Accessibility Testing"

Revision as of 02:46, 17 February 2009

Accessibility is not the same as usability, but it overlaps because a lot of disabilities make it harder to deal with stuff which doesn't have great usability to begin with.

Some accessibility features can be tested automatically with tools - eg markup validation, colour contrast analysis - but much of it comes down to human judgement.

Good description here of what can and can't be tested: What accessibility testing is possible Even that site misses some stuff - contrast levels appropriate for dyslexics, moving image problems that people with some neuro deficits have, everything important being keyboard-only accessible, and probably other things.

General

These things are generally good things to do and also have implications for disability accessibility.

• Pages need to validate fully to whatever DTD they've specified.
• Pages should degrade gracefully in the absence of capabilities for Flash, JavaScript, images, CSS, etc.
• Proper semantic markup should be used, eg headers for headings, ACRONYM and ABBR tags, EM/STRONG rather than I/B tags.

This especially. The site should rewrite I/B tags, made in posts, into EM/STRONG, instead of the other way around which is what the current LJ code does. And the headers, oh my god, the headers. branchandroot

I think globally rewriting all I/B to EM/STRONG in users' entries is inappropriate; not everything italic is emphasised, and not everything bold is strongly emphasised. Sometimes italics are used for other purposes, too (e.g. in book titles). -- Pne 08:34, 16 February 2009 (UTC)

*considers* That's a good point. Very few people are at all on board with the semantic difference, so whichever way this is done there will be accessibility slippage. I revise my suggestion to "leave the user-entered html tags as is instead of changing them at all". branchandroot 20:05, 16 February 2009 (UTC)

I'd hope that any screen reader software would be able to interpret I/B tags as EM/STRONG. This should be tested though. If it's found that they don't, perhaps allowing users the ability to convert them through the use of styles could be a solution? I agree that the author shouldn't be forced into using one or the other, and should be allowed to choose appropriately. Touchy issue, this one. --Textish 00:47, 17 February 2009 (UTC)

Blindness

This is the disability people usually think about when they discuss web accessibility, but it's important to remember it's not the only one.

• CAPTCHAs need audio options.

As discussed below, CAPTCHAs are difficult for people with disabilities across the board. Perhaps some method of e-mail verification might replace the need? This topic deserves much discussion. --Textish 01:11, 17 February 2009 (UTC)

• Screen reader friendliness. Try very hard to get general screen reader users to do testing for us, rather than sighted people using screen readers which is a bad approximation.
  • JAWS
  • WindowEyes
  • VoiceOver
  • NVDA
  • Orca?
  • others?

This is important. I believe that sighted users can, however, test simple screen readers, such as those included in Dragon NaturallySpeaking and other simple screen readers that do not offer much more than screen scraping. I'd be willing to volunteer time to testing Dragon NaturallySpeaking's screen reading compatibility myself. --Textish 01:11, 17 February 2009 (UTC)

• Check tab order for everything, especially things which are AJAXey and therefore have changing tab order

Relevant reading:

• WebAIM screen reader survey results

Color Blindness

• Things which are usually signalled to users through colour changes in interface elements must have some other signalling mechanism (such as change of image shape) in addition

Deafness

• Any official videos put on the site (eg "how to use" screencasts) should have captions available.

Deafblindness

This disability is a double-whammy as many of the solutions to problems faced by blind or deaf users rely on the other sense - eg audio alternatives to CAPTCHAs.

• CAPTCHAs are completely inaccessible and an alternative such as emailing support needs to be available whenever CAPTCHAs are used. Currently I think this is only journal creation, if that.
• Even captions for videos will probably be inaccessible. Separate methods of obtaining the information such as transcripts are needed.
• Information needs to be concise. Many deafblind users will be using braille displays which give a single line of text that's 40 characters long.

Dyslexia

• Contrast (too high can be a problem)
• CAPTCHAs can be inaccessible, even with audio alternatives, due to visual and auditory "noise"

Keyboard-only Users

• Make sure anything triggered usually by mouse movements (eg :hover attributes) which is needed for site use has a keyboard-accessible alternative.
• Check tab order for everything, especially things which are AJAXey
• Potentially hideable alternative text for all images which are used for site navigation and control (e.g. the "tag/memory/etc." icons) for direct keyboard access. Note this is not the same as alt tags.
• Must have alternatives in places where you would usually control-click to select multiple elements off a drop-down list (e.g. choosing tags, where the keyboard alternative currently is to remember the names of your tags and type them in).

Low Vision

• Contrast (low is a problem)
• CAPTCHAs need audio equivalents
• Default font size should be reasonable
• Robustness of layout to font size increases (eg command-+/ctrl-+) must be tested.
  • IE
  • Firefox
  • Safari
  • Opera
  • Others?
• For those browsers that have the capability, page size increases - scaling images as well as text - must also be tested.
  • Firefox3
  • Beta versions of Safari?
  • Opera
  • Others?
• Alternate layouts with less visual "clutter"/"noise" may be needed for some people (equivalent to LJ's Lynx site scheme)

Mouse use problems

Users who are able to use a mouse but have some difficulty with it. Keyboard equivalents are a solution to some in this group, but some in this group will have no ability to use a physical keyboard either - only an on-screen keyboard (again, requiring mousing) will be used.

• Mouse targets need to be as large as possible.
• Minimise/eliminate use of any elements which require a mouse click-and-drag as this is most difficult for many users.
• Remember Fitt's law.

Neurological Problems

This category would include people on the autism spectrum, people with traumatic brain injuries, stroke survivors, and several other groups.

• Anything on the page that moves (Flash, animated GIFs, etc.) can be sufficiently distracting to make the page unreadable.
• CAPTCHAs can be inaccessible, even with audio alternatives, due to visual and auditory "noise"

Speech Recognition Users

All of the issues listed for keyboard users apply to speech recognition users.

• Systems we must test:
  • Dragon NaturallySpeaking Windows speech recognition
  • MacSpeech Dictate OS X speech recognition
  • Windows Vista built-in speech recognition

Resources

• Color Contrast Analyser checks for contrast which is too high as well as contrast that is too low.