Task 'testClasses' not found in project ':google-play-services-first-party'

I have an existing android project.

I want to add unit-tests using robolectric.

However, the project structure is weird and not standard.

1) How should I set the test path in gradle to be the custom one?

2) When I run the test via andorid-studio, I get this error:

Error:FAILURE: Build failed with an exception.

* What went wrong:
Task 'testClasses' not found in project ':google-play-services-first-party'.

* Try:
Run gradle tasks to get a list of available tasks. Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

If I fix the project test structure, this should solve this as well?