(Question) Is it possible to add a file to the preprocessor file list programmatically?

I maintain the [Karma Rollup preprocessor](https://github.com/jlmakes/karma-rollup-preprocessor), and I've encountered some challenges with `autoWatch: true` and Rollup: a changed file will be reprocessed but not the dependencies it imports... so you can easily end up with stale tests.

I have hacked a solution together where I map the dependencies of each file, and manually change the accessed/modified times of those files during processing to force the Karma watcher to reprocess them as well.

The problem is that tests re-run for each manually modified file, which for a file that is used in many places can trigger a large number of re-runs.

Going through the source, I thought injecting `file-list` might be the answer so that I could manually add the dependency paths to it... but it creates a circular dependency error.

### Is it possible to add files to the preprocessor file list programmatically from within the preprocessor?