Making changes to environment settings in a Jenkinsfile is an important feature available in the editor, but none of our existing tests cover this path. A simple ATH test (or even an addition to another, existing test) would be a nice coverage improvement.
An offline test could create a repository including an existing Jenkinsfile, stored in our resources directory, like we're doing here. This existing Jenkinsfile might include something like:
SOME_VARIABLE = "old-boring-setting"
which we could then use the editor to change into
SOME_VARIABLE = "new-awesome-setting"
NEW_VARIABLE = "another-new-thing"
And then verify that the changes were made correctly.