How to test Google+ sign-in with Robotium?

Question

I created an LoginActivity using Android Studio "new project" wizard. I added dependency on Robotium and wrote a simple test, extending from InstrumentationTestCase:

    launchActivity("com.my.package", LoginActivity.class, new Bundle());
    solo.waitForActivity(LoginActivity.class, 1000);
    solo.clickOnText("Sign in"); //inside my Activity
    assertTrue("Not G+", solo.waitForActivity("GrantCredentialsWithAclActivity", 4000));
    solo.clickOnText("Sign in"); //on Google+ dialog

But the "Not G+" assertion fails.

I've found from dumpsys that com.google.android.gms/.auth.login.GrantCredentialsWithAclActivity is Google+ sign-in activity on my device. How it translates to name parameter from solo.waitForActivity(name, timeout)? Am I even able to click anything on Google+ dialog?