Longdesc tests

Some tests proposed by Charles McCathie Nevile for the HTML Image Description Extension specification. All tests are ©chaals, and are made available under the terms of the W3C software license.

Multifunction tests

There are tests for descriptions under different combinations of circumstances - images included "normally", as data: URIs, or missing, with the descriptions internal or external to the page, as a data: URI, or in a location only reachable by taking into account the base element

The same tests can be used to determine whether

• the User Agent informs the user that there is a description;
• the User Agent enables the user to access the description; and
• the description is communicated through system accessibility APIs.

Longdesc value as data:URI

• data:URI image with data:URI description
• Empty image with data:URI description
• External image with data:URI description (with extra spaces)
• External image with data:URI description

Longdesc value as external URI

• data:URI with External description
• Empty image with an External description
• External image with External description (with extra spaces)
• External image with External description

Longdesc value as internal URI (same page link)

• data:URI with Internal description.html
• Empty image with an Internal description.html
• External image with an Internal description (with extra spaces
• External image with an Internal description

Longdesc value as a fragment in an external URI

• data:URI with External description fragment
• Empty image with an External description fragment
• External image with External description fragment (with extra spaces around the URL)
• External image with External description fragment

Longdesc value as external URI in presence of a base element

• External image with External Description (relative base element set)
• External image with External Description (absolute base element set)

longdesc inside an iframe

The test Image in an iframe with External Description loads an an image with a long description from a separate document using an iframe. To pass, the tester must be able to access the "Longdesc test Pass Page" which consists of the word "Pass" in a heading level 1 followed by a long description of the image.

Automated browser tests

Longdesc value updated by javascript tests whether the HTML attribute reflects changes made by javascript. To pass, the browser must be redirected to pass.html which has the word "Pass" as a heading followed by a description of the image. Displaying the "Longdesc test Fail Page" would indicate a failure of this test. This test requires javascript to function.

Validation tool tests

The test Invalid long description (plain text) contains an invalid long description and can be used to test User Agent and validation tool handling. Note Handling of invalid longdescs by user agents is currently undefined.

The test Invalid long description (empty attribute) contains an invalid long description and can be used to test User Agent and validation tool handling. Note Handling of invalid longdescs by user agents is currently undefined.

The test Invalid long description fragment (the target is an empty element) contains a pointer to an invalidly marked long description as a fragment of a document and can be used to test validation tool handling.

Results

Supporting files

The following files are used to make one or more of the tests work:

• README-offline.html is this file, for use when the repository is simply posted somewhere.
• README.md is the equivalent content of this file in markdown format, for use with the github.com repository.
• fail.html
• pass.html
• fail-fragment.html
• pass-fragment.html
• picture.png
• rebased/picture2.png
• rebased/fail.html (despite the name, this is a pass page used to test what happens when a base element is used)