How do I run a specific Dart _test file with pub run test?

I have a bunch of files in my test_dir and the problem is that they must be run separately, because one of them is testing the code that can only be run in the browser and the other is testing code that can only be run in the backend.

Now, I know there's a -n argument to pub run test for specifying test name, but how do I run a specific file? It's not very clear from the documentation and I wasn't able to successfully accomplish that.