To use Android Support Fragment v4 in Robolectric 3.0 you must add gradle dependency in /app/build.gradle
testCompile 'org.robolectric:shadows-support-v4:3.0'
Then import into your Robolectric testing java class
import org.robolectric.shadows.support.v4.SupportFragmentTestUtil;
then you can create/start android support v4 fragments within your Robolectric testing java class for unit testing:
SupportFragmentTestUtil.startVisibleFragment(fragment);
Cross posted to StackOverflow Android Robolectric Support Fragment.