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Accessibility Testing

Testing for accessibility involves a combination of automated testing tools and manual testing procedures using your keyboard. You can add screen readers, switches, or other devices as necessary, but you can find the majority of problems without any extra equipment or software.

First, use a browser extension to catch basic problems with HTML structure, form labels, color contrast, and link and button names. Then try navigating the screen using your keyboard to tab between items. These two steps alone will uncover many issues. You can then go further by setting up a screen reader or using browser bookmarklets to highlight specific problems.

You can examine problems as they come up in the browser extensions, or start with a checklist to tackle things in a more logical order.

Testing with Browser Extensions

Browser extensions are great for testing the overall accessibility of a page and finding straightforward errors. However, these tools can’t test criteria that require subjective consideration, and they can sometimes give false positives.

Testing Keyboard Navigation

Keyboard navigation is not enabled by default in some browsers.

  • In Chrome, to go Settings > Accessibility. Turn on “Navigate pages with a text cursor” and “Show a quick highlight on the focused object.”
  • In Safari, go to Settings > Advanced and check “Press Tab to highlight each item on a webpage” (screenshot)

Place your cursor in the address bar and then press the tab key to move sequentially through focusable items. Use Shift-Tab to go back. Press Enter or Space to open dropdowns or activate buttons. Within dropdown menus and tab sets, you should be able to use the arrow keys to navigate the subsections. Use Escape to close dropdowns, popups, and modals.

Make a note of any controls that can’t be reached using the keyboard, or any areas where you lose track of which item has focus. Items should be highlighted in more or less the same order as a person would read them; if your focus jumps to other areas of the page out of the expected order, make a note of that as well.


Testing with Screen Readers

Getting started with screen readers can be challenging because they lack visible controls. Find a cheat sheet of keyboard shortcuts for the software you’re using, and have it ready before you begin.

Setting up a screen reader testing environment on your computer, Sara Soueidan

Getting started with screen reader testing, Harvard University Digital Accessibility team

Guides to keyboard shortcuts in screen readers:

To speed up testing, you can turn on the screen reader’s feature to display a transcript of the page. This shows exactly what the screen reader will announce. For Macs, the Auto VO tool automates VoiceOver tests. The transcript will update live as you move through interactive controls.

Testing Color Contrast

The various accessibility testing browser extensions will flag instances of insufficient color contrast. To test new color combinations, there are numerous tools. The most basic are:

To find new accessible color combinations, try:

Stylesheets and Bookmarklets for Specific Issues

Some developers have assembled stylesheets that you can apply to your pages to highlight specific accessibility problems.

Automated Testing

accessibility/testing.txt · Last modified: 2023/07/10 14:28 by scl

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