Certainly possible, but will need some work. Right now all the theme javascript files are bundled together into one file. We would need to make sure tests are put in a new, separate bundle, so that they don’t get served to regular visitors. And then once that’s done, make a way to run qunit tests for a single theme.
The other thing to consider is that we don’t make the /qunit route available on production servers. Since themes are often developed on production servers, we may need to rethink this 