Building on the successful experiment in T351707, we want to switch the Cite extension web tests over from Selenium to Cypress. This framework comes with much better debugging affordances, and seems to run much faster in CI which allows us to write more comprehensive web tests. Web testing will be especially useful for working on visual editor integration for Cite.

Steps to implement:

• Copy over and adapt setup files, to install Cypress in the Cite code base.
• Port tests/selenium/specs/backlinks.js and supporting file cite.page.js to run under the Cypress environment, in a second patchset.
• Run the new suite in CI, replacing the previous selenium integration.
• Delete the selenium test suite.
• Add documentation to mediawiki.org