Eu uso ele...
Felipe, para ter auto complete no Android Studio tem um pequeno truque, definir as dependencias de test tanto como testCompile e instrumentTestCompile
testCompile 'junit:junit:4.10'
testCompile 'org.robolectric:robolectric:2.3-SNAPSHOT'
testCompile 'com.squareup:fest-android:1.0.+'
testCompile "org.mockito:mockito-all:1.9.5"
testCompile 'com.squareup.retrofit:retrofit-mock:1.3.0'
instrumentTestCompile 'junit:junit:4.10'
instrumentTestCompile 'org.robolectric:robolectric:2.3-SNAPSHOT'
instrumentTestCompile 'com.squareup:fest-android:1.0.+'
instrumentTestCompile "org.mockito:mockito-all:1.9.5"
instrumentTestCompile 'com.squareup.retrofit:retrofit-mock:1.3.0'