[racket-dev] Testing 'disappeared-use bindings and Check Syntax

In light of PR 11469 (http://bit.ly/hvvT90), I'd like to write test
cases to check that Redex sets 'disappeared-use in a way that makes
Check Syntax's renaming work properly.

I was hoping there would be some kind of Check Syntax mixin that I
could apply to an editor to get a class that lets me insert a program
and rename specific variables, but that does not seem to be the case.

All I see is a DrRacket tool interface. Is there any hope for working
at that level (e.g., by scripting a DrRacket session that opens a
file, clicks Check Syntax, right-clicks a variable, etc.)?