The add link selenium tests (selenium/specs/addlink.js) exercise various code paths in the AddLink visual editor plugin, but they do not check that the saved edit diff is as expected. To avoid problems similar to T311916: "Add an image" structured edits add a blank line instead of an image, let's add a verification on the diff contents from edits saved via addlink.js selenium test.

Acceptance Criteria

1. addlink.js selenium tests should verify the saved contents

Completion checklist

Functionality

• The patches have been code reviewed and merged
• The task passes its acceptance criteria

Engineering

• There are existing and passing unit/integration tests
• Tests for every involved patch should pass
• Coverage for every involved project should have improved or stayed the same

Design & QA

• If the task is UX/Design related: it must be reviewed and approved by the UX/Design team
• Must be reviewed and approved by Quality Assurance.

Documentation

• Related and updated documentation done where necessary
  • Internal technical changes: internal repository documentation must be updated (README.md, JSDoc, PHPDoc)
  • Infrastructure technical changes: technical changes that reflect on environment, infrastructure, endpoints or any other area of interest for technical contributors should be reflected on Extension:GrowthExperiments or Extension:GrowthExperiments/Technical documentation pages.