use test utils in head_test
use test utils in head_test

alileza/prometheus,Gouthamve/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,kangwoo/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,prometheus/prometheus,kangwoo/prometheus,alileza/prometheus,alileza/prometheus,kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,Gouthamve/tsdb,prometheus/prometheus,GoogleCloudPlatform/prometheus,prometheus/tsdb,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,prometheus/prometheus