Currently there is no easy way to be able to attach a debugger (for example from Android Studio) to the junit tests targets, as there is no support for --wait-for-debugger in the generated scripts in out/.../bin/run_foo_junit_tests.

It would be great if those targets worked as other targets.

This was recently discussed in the following thread on chromium-dev@:
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/mm_68bVKf0M/discussion

That also links to documentation (possibly outdated) for how to do this using Eclipse and setting up a Run-project manually:
https://chromium.googlesource.com/chromium/src/+/master/docs/eclipse.md#Run-Robolectric-JUnit-tests