Sc1 1 1 Text Alternative

Created by: Frank Berker

Description

This test checks that non-text elements conveying information are providing sufficient textual alternatives or, if purely decorative, are hidden from assistive technologies.

Background

• WAI-ARIA 1.0 - Text Alternative Computation
• ARIA6: Using aria-label to provide labels for objects
• ARIA10: Using aria-labelledby to provide a text alternative for non-text content
• F38: Failure of Success Criterion 1.1.1 due to not marking up decorative images in HTML in a way that allows assistive technology to ignore them
• F30: Failure of Success Criterion 1.1.1 and 1.2.1 due to using text alternatives that are not alternatives (e.g., filenames or placeholder text)
• F39: Failure of Success Criterion 1.1.1 due to providing a text alternative that is not null (e.g., alt=”spacer” or alt=”image”) for images that should be ignored by assistive technology
• F65: Failure of Success Criterion 1.1.1 due to omitting the alt attribute on img elements, area elements, and input elements of type “image”
• G196: Using a text alternative on one item within a group of images that describes all items in the group
• H2: Combining adjacent image and text links for the same resource
• H30: Providing link text that describes the purpose of a link for anchor elements
• H37: Using alt attributes on img elements
• H53: Using the body of the object element
• H67: Using null alt text and no title attribute on img elements for images that AT should ignore

Assumptions

• The techniques used for providing a textual alternative are accessibility supported. For more information read Accessibility Support.
• All elements are contained in the mark-up code in the examined web page snapshot. F20: Failure of Success Criterion 1.1.1 and 4.1.2 due to not updating text alternatives when changes to non-text content occur is not tested.
• Groups of images consist of img elements that are adjacent to each other and not wrapped in containers.
• The smallest readable font can be displayed on a matrix with a height of 5 and a width of 3. Smaller elements are considered decorative automatically.

Test properties

Test procedure

Selector

Test mode: automatic

//*[self::img or self::input[@type="image"] or self::area or self::embed or self::object]

Step 1: check element type (F65)

Test mode: automatic

Check if the element is of type <img>,<area> or input[type=”image”]

if yes, continue with Step 2: check mandatory attributes (F65)

else continue with Step 8: compute text alternative

Step 2: check mandatory attributes (F65)

Test mode: automatic

Check if one of the following attributes is present: aria-labelledby with valid destinations or alt , aria-label, title.

if yes, continue with Step 3: check for img siblings (ARIA10 and G196)

else return

Step 3: check for img siblings (ARIA10 and G196)

Test mode: automatic

Check if the selected element is an img element and has adjacent siblings of type img.

if yes, continue with Step 4: ask for informational or functional group of images (ARIA10 and G196)

else continue with Step 8: compute text alternative

Step 4: ask for informational or functional group of images (ARIA10 and G196)

Test mode: automatic

User Input Question:

if yes, continue with Step 5: check for aria-labelledby implementation (ARIA10)

else continue with Step 8: compute text alternative

Step 5: check for aria-labelledby implementation (ARIA10)

Test mode: automatic

Check if the parent element of the current group has role="img" and an aria-labelledby attribute.

if yes, continue with Step 6: ask if sufficiently described by textual alternative (ARIA10)

else continue with Step 7: ask if sufficiently described by textual alternative (G196)

Step 6: ask if sufficiently described by textual alternative (ARIA10)

Test mode: automatic

Concatenate the results of Text Alternative Computation Algorithm run on all elements referenced in the aria-labelledby attribute and assign it to variable T1.

All items of the group should be removed from the set of selector-matches after this step.

User Input Question:

if yes, return

else return

Step 7: ask if sufficiently described by textual alternative (G196)

Test mode: automatic

Concatenate the results of Text Alternative Computation Algorithm run on all images and assign it to variable T1.

All items of the group should be removed from the set of selector-matches after this step.

User Input Question:

if yes, return

else return

Step 8: compute text alternative

Test mode: automatic

Use the Text Alternative Computation Algorithm to compute the textual alternative provided and assign it to variable T1.

If T1 is empty and the current element is an <img>

continue with Step 9: check if child of anchor (H2)

else if T1 is empty and the current element is NOT an <img>

continue with Step 11: check dimensions (no text alternative)

else if T1 is NOT empty

continue with Step 13: check text alternative validity (F30 and F39)

Step 9: check if child of anchor (H2)

Test mode: automatic

Check if the img is child of an <a> element.

If yes, continue with Step 10: check for anchor text (H2)

else continue with Step 11: check dimensions (no text alternative)

Step 10: check for anchor text (H2)

Test mode: automatic

Note: The img has no textual alternative at this test step.

Check if the parent anchor element or any of its children contains text.

if yes, return

else return

Step 11: check dimensions (no text alternative)

Test mode: automatic

Check if the elements height is less or equal 5px or the elements width is less or equal 3px.

if yes, return

else Continue with Step 12: ask if decorative (no text alternative)

Step 12: ask if decorative (no text alternative)

Test mode: automatic

User Input Question:

if yes, return

else return

Step 13: check text alternative validity (F30 and F39)

Test mode: automatic

Use the Validate Text Alternative algorithm to check if the textual alternative value is non-empty, as defined (contain 2 or more characters that are not white space characters or punctionmarks), not a filename, an URL or a placeholder text.

if valid, continue with Step 14: check dimensions (valid text alternative) (F38)

else return

Step 14: check dimensions (valid text alternative) (F38)

Test mode: automatic

Check if the elements height is less or equal 5px or the elements width is less or equal 3px.

if yes, continue with Step 16: check for empty alt (F38)

else continue with Step 15: ask if decorative (valid text alternative) (F38)

Step 15: ask if decorative (valid text alternative) (F38)

Test mode: automatic

User Input Question:

if yes, continue with Step 16: check for empty alt (F38)

else continue with Step 17: ask if sufficiently described by textual alternative

Step 16: check for empty alt (F38)

Test mode: automatic

Note: The image has a textual alternative at this test step.

If the current element is an img, check, if an empty alt attribute or role="presentation" is provided.

if yes, return

else return

Step 17: ask if sufficiently described by textual alternative

Test mode: automatic

User Input Question:

if yes, return

else continue with [[#Step 18: ask if sufficiently described by adjacent text]]

Step 18: ask if sufficiently described by adjacent text

Test mode: automatic

User Input Question:

if yes, return

else return

• Activity diagram of transitions between steps 1 to 18 [[File:1.1.1. test step overview.png|frameless|1046px|Graphical alternative of steps one to eighteen]]
• Activity diagram of test steps related to techniques and failures [[File:1.1.1. text alternative.png|frameless|1069px|Detailed graphical alternative to text above]]