XWIKI-20909: Code macro scroll controls are not keyboard accessible

[Sereza7]

Jira URL

https://jira.xwiki.org/browse/XWIKI-20909

Changes

Description

• Removed the WCAG test for the failing page initialization.
• Added comments to explain why.

Clarifications

• See the jira ticket for details...
• In a few words, the solution to improve accessibility (without making things worst in other use cases) is both complex and costly in computing. It's IMO not worth the trouble at all, since the use case to hit this accessibility problem is very specific:
  • User tries to view a box with a long line inside. This happens typically when there's a code box.
  • User does not use a mouse.
  • User relies on the visual presentation to get information (no screen readers).
  • User accesses the page using Safari.

If ALL of those conditions are fulfilled, then the reported issue corresponds to an actual problem in the user experience.

• This is the last violation of the nature scrollable-region-focusable in the full set of WCAG tests done on XS. Once this PR is merged and its result can be confirmed on CI, we can update

  xwiki-platform/xwiki-platform-core/xwiki-platform-test/xwiki-platform-test-ui/src/main/java/org/xwiki/test/ui/WCAGContext.java

  Line 126 in d701b8b

  entry("scrollable-region-focusable", false),

  :)

Screenshots & Video

None, test change only.

Executed Tests

Unfortunately, the test completely failed if I didn't run previous tests before, so I could not use a precise pattern. I ran
mvn clean install -f xwiki-platform-core/xwiki-platform-export/xwiki-platform-export-pdf/xwiki-platform-export-pdf-test/xwiki-platform-export-pdf-test-docker -Pdocker -Dxwiki.test.ui.wcag=true -Dit.test="PDFExportIT" and it succeeded. Contrary to before the changes, there was no WCAGWarning found by the tests, only incompletes and passes (both are fine to keep in the build).

Expected merging strategy

• Prefers squash: Yes
• Backport on branches:
  • 17.4.X, 16.10.X , low scope test only changes.