I noticed, that the class https://github.com/javaparser/javaparser/blob/master/javaparser-core-testing/src/test/resources/com/github/javaparser/storage/B.java is empty.

This fact might cause false alarms when automated tools are checking whether all sources are not empty.

I think that very simple solution would be to add content like //empty, in that way the functionality of CompilationUnitTest would stay the same, and the tools checking non-empty files would be satisfied too.

Let me provide a simple PR fixing it.