Add a test for the following scenario: A user performs an action that results in broken wikicode being visible on the rendered HTML page. The easiest way to test for some of these errors is to check if there is anything with the HTML class "error" when the page is rendered and whether the error existed in the previous version.
You can get rendered version of page like this where oldid is the revision id
Example change
Other edit tests are located in autoreview.py.