The issue that bubbled up in T373661: "Cannot read properties of null (reading 'keyedNodes')" opening Basic citation in 2017 Source Editor could have been easily detected with a basic test covering that codebase. Let's create one to at least cache the most obvious issues that might be special to the WT2017 Cite use case.

Acceptance criteria:

Add an e2e test that

• Uses the Cite dialog to create a basic reference in WT2017 editor
• Uses the Cite dialog to create a VE-Cite tool template based reference in the WT2017 editor

Implementation:
We would need to login and set the user preference of the test user, so that source editing defaults to WT2017. This can be done via the API before the actual test is executed. See for example in this code base, where the same is done using selenium: https://gerrit.wikimedia.org/g/mediawiki/extensions/CodeMirror/ /7890ebc3349f4857cc26f0651d9ab685d6f58a8e/tests/selenium/userpreferences.js#32