Empty Test Suite on Android test support code

I have classes that mock some functionality in the test code. They are only relevant in the test code, so they are written in the test package.

I want to create a run configuration that will run all the tests in all the packages under the test package.

However, because those classes exist, and are not technically test code. They do not have @Test marked on any of their methods.

And thus the runtime fails because there are classes with no test methods in them.

How to configure it so that those classes will be ignored for running tests?