Unit test the "Roles and Capabilities" Codex page against core

[johnbillion]

The ​Roles and Capabilities page on the Codex can be fetched in a test and its contents tested against the roles and capabilities that are tested in core, to ensure that all capabilities used in core are listed on the page.

[johnbillion]

38193.patch​ is a (currently failing) test that checks the Codex page for the existence of an element with an id attribute matching that of every capability used in core. This ensures that the Capabilities list on the page includes an entry for every capability.

The tests are currently failing because the page is missing entries for the following capabilities (which is the reason I decided to write this test).

• create_sites
• delete_sites
• upload_plugins
• upload_themes
• customize
• delete_site

I might expand on these tests some more and increase the specificity.

Make yourself known if you think these tests should not be in core.

[netweb]

Maybe add the tests to the @group external-http?

[johnbillion]

Patch which adds the external-http group, and adds a test for roles in addition to capabilities.

The Codex page has been updated so these tests now pass, with the exception of the new capabilities introduced in #35614.