When I run `dub test` on a project that does not use any `unittest { ... }` sections, then I would expect D to either say something like "0 tests run", or perhaps complain that no unit tests are implemented.

Instead, I see a low-level error like this:

Error: function `D main` conflicts with static import dub_test_root.main

Which doesn't really indicate what is going wrong at a level the coder would easily understand.