Add tests for group_left/group_right
Add tests for group_left/group_right

dmilstein/prometheus,datajet-io/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,Conorbro/prometheus,dmilstein/prometheus,gottwald/prometheus,alileza/prometheus,ton31337/prometheus,PrFalken/prometheus,brancz/prometheus,tattsun/prometheus,Gouthamve/prometheus,amorken/prometheus,tomwilkie/prometheus,dmilstein/prometheus,JavierZunzunegui/prometheus,slok/prometheus,brancz/prometheus,JavierZunzunegui/prometheus,slok/prometheus,agaoglu/prometheus,agaoglu/prometheus,dsymonds/prometheus,yanghongkjxy/prometheus,tomwilkie/prometheus,dmilstein/prometheus,slok/prometheus,AlekSi/prometheus,alileza/prometheus,Gouthamve/prometheus,tomwilkie/prometheus,Conorbro/prometheus,msiebuhr/prometheus,keegancsmith/prometheus,kzittritsch/prometheus,datajet-io/prometheus,dsymonds/prometheus,datajet-io/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,Stackdriver/stackdriver-prometheus,sudhi-vm/prometheus,tattsun/prometheus,PrFalken/prometheus,keegancsmith/prometheus,SaltedMan/prometheus-annotated,Conorbro/prometheus,ton31337/prometheus,adamron1/prometheus,GoogleCloudPlatform/prometheus,amorken/prometheus,Colstuwjx/prometheus,keegancsmith/prometheus,gottwald/prometheus,Gouthamve/prometheus,agaoglu/prometheus,prometheus/prometheus,Conorbro/prometheus,SaltedMan/prometheus-annotated,adamron1/prometheus,yanghongkjxy/prometheus,keegancsmith/prometheus,amorken/prometheus,prometheus/prometheus,ton31337/prometheus,yanghongkjxy/prometheus,gottwald/prometheus,kzittritsch/prometheus,brancz/prometheus,msiebuhr/prometheus,ton31337/prometheus,datajet-io/prometheus,keegancsmith/prometheus,prometheus/prometheus,msiebuhr/prometheus,kangwoo/prometheus,amorken/prometheus,PrFalken/prometheus,tomwilkie/prometheus,tattsun/prometheus,alileza/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,Colstuwjx/prometheus,SaltedMan/prometheus-annotated,sudhi-vm/prometheus,gottwald/prometheus,agaoglu/prometheus,msiebuhr/prometheus,AlekSi/prometheus,adamron1/prometheus,alileza/prometheus,PrFalken/prometheus,adamron1/prometheus,dsymonds/prometheus,Stackdriver/stackdriver-prometheus,Colstuwjx/prometheus,tattsun/prometheus,SaltedMan/prometheus-annotated,brancz/prometheus,JavierZunzunegui/prometheus,kangwoo/prometheus,slok/prometheus,Stackdriver/stackdriver-prometheus,AlekSi/prometheus,sudhi-vm/prometheus,kzittritsch/prometheus,dsymonds/prometheus,kangwoo/prometheus,yanghongkjxy/prometheus,sudhi-vm/prometheus,Colstuwjx/prometheus,Gouthamve/prometheus,prometheus/prometheus,kzittritsch/prometheus,Stackdriver/stackdriver-prometheus,AlekSi/prometheus,JavierZunzunegui/prometheus,GoogleCloudPlatform/prometheus