right now, the testing is kinda informal: you can just go to http://www.maxheld.de/ghpages/, and ideally, you should see the last commit sha there if things worked out.

I'd like to have a more fully programmatic way of testing this action, especially as more people rely on it, but I haven't quite figured out an elegant way to do this.

I'd probably involve talking with the GitHub API somehow, to check that the action (given some boilerplate setup) works as intended.

I am also developing this as part of the R package ghactions where I have good unit/integration testing tooling, and I'm not quite sure how that would work here.

Maybe postpone this to a later date, maybe github comes up with something.